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1. Select the web xm1 Select the References tab in the property sheet Click the Resource References Property and open the property editor Click Add Type jdbc BookDB in the Name field Leave the default type javax sq DataSource OMAN DAMA UMN Leave the default authorization Container 10 Choose Shareable for Sharing Scope Mapping the Web Application J NDI Name to a Data Source Since the resource reference declared in the Web application deployment descriptor uses a JNDI name to refer to the data source you must connect the name to a data source defined by the application server as follows 1 Select the Web module Expand the WEB INF node Select the web xm1 file Select the Sun ONE AS property sheet Select the Resource Reference Mapping property and open the property editor 6 For the Resource Reference Name jdbc BookDB type jdbc BookDB in the JNDI Name field nA BW N Further Information For more information about Web applications refer to the following e Resources listed on the Web site http java sun com prod ucts serv let e The Java Servlet 2 3 Specification 46 INTRODUCTION TO WEB APPLICATIONS e Getting Started with Sun ONE Application Server 7 located at lt S1AS7_HOME gt docs getting started ch6 database setup html contains further information on how to set up the application server to access a database 3 Java Serviet Technology Stephanie Bodoff
2. As soon as the Web began to be used for delivering services service providers recognized the need for dynamic content Applets one of the earliest attempts toward this goal focused on using the client platform to deliver dynamic user experiences At the same time developers also investigated using the server plat form for this purpose Initially Common Gateway Interface CGD scripts were the main technology used to generate dynamic content Though widely used CGI scripting technology has a number of shortcomings including platform dependence and lack of scalability To address these limitations Java Servlet technology was created as a portable way to provide dynamic user oriented con tent Whatis a Serviet A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request response programming model Although servlets can respond to any type of request they are commonly used to extend the applications hosted by Web servers For such applications Java Servlet technology defines HTTP specific servlet classes 47 48 JAVA SERVLET TECHNOLOGY The javax servlet and javax servlet http packages provide interfaces and classes for writing servlets All servlets must implement the Servlet interface which defines life cycle methods When implementing a generic service you can use or extend the GenericServ let class provided with the Java Servlet API The
3. java 201 java 202 java 203 java 204 java 205 java 206 java 207 41 42 INTRODUCTION TO WEB APPLICATIONS java java 7 Rows Selected java java SQL gt java java COMMIT java OK Add PointBase J DBC Driver to the Application Server s Classpath You can add the PointBase JDBC driver to the application server s classpath in one of two ways e Copy the PointBase JDBC driver library lt S1AS7_HOME gt pointbase client_tools lib pbclient42RE jar to the lib directory of your application server instance For example lt S1AS7_HOME gt domains domain1 server1 1ib e Specify the location of the PointBase driver in the Classpath Suffix field in the application server s configuration a Start the administration console by opening the URL http local host 4848 in a browser Select the server node Select the JVM Settings tab Click the Path Settings link Add lt S1AS7_HOME gt point base client_tools lib pbclient42RE jar to the Classpath Suffix text area f Click Save oad ogo Then restart the application server to make the server aware of the driver 1 Click the General tab of the administration console 2 Click Stop to stop the server and Start to restart it DEFINING A DATA SOURCE IN SUN ONE APPLICATION SERVER 7 Defining a Data Source in Sun ONE Application Server 7 Data sources in the Sun ONE Application Server 7 implement connection pool ing
4. The J 2EE Tutonal forthe Sun ONE Platfiom Eric Armstrong Stephanie Bodoff Maydene Fisher Dale Green Kim Haase February 13 2003 Copyright 2003 Sun Microsystems Inc 4150 Network Circle Santa Clara California 95054 U S A All rights reserved U S Government Rights Commercial software Government users are subject to the Sun Microsystems Inc standard license agreement and applicable provisions of the FAR and its supple ments This distribution may include materials developed by third parties Sun Sun Microsystems the Sun logo Java J2EE JavaServer Pages Enterprise JavaBeans Java Naming and Directory Interface EJB JSP J2EE J2SE and the Java Coffee Cup logo are trademarks or registered trademarks of Sun Microsystems Inc in the U S and other countries Unless otherwise licensed software code in all technical materials herein including articles Fads sam ples is provided under this License Products covered by and information contained in this service manual are controlled by U S Export Con trol laws and may be subject to the export or import laws in other countries Nuclear missile chemical biological weapons or nuclear maritime end uses or end users whether direct or indirect are strictly pro hibited Export or reexport to countries subject to U S embargo or to entities identified on U S export exclusion lists including but not limited to the denied persons and specially designated nationa
5. areaCode phoneNumber customer setEmai lAddress email clientutil OrderGenClient AddressBean address new clientutil OrderGenClient AddressBean address setStreet street address setCity city address setState state address setZip zip clientutil OrderGenClient OrderBean order 414 THE COFFEE BREAK APPLICATION new clientutil OrderGenClient OrderBean ArrayList newlis new ArrayListQ for Iterator c newlis iterator c hasNextQ LineItemBean li CLineItemBean c next Q clientutil OrderGenClient LineItemBean lib new clientutil OrderGenClient LineItemBeanQ lib setCoffeeName 1i getCoffeeName lib setPounds 1i getPounds lib setPrice li getPrice newlis add 1lib order order order setId orderId setCustomer customer setLineItems newlis order order setTotal total setAddress address OrderCaller ocaller new OrderCaller distributor clientutil OrderGenClient ConfirmationBean confirmation ocaller placeOrder order cbconfirmation setShippingDate confirmation getShippingDateQ OrderConfirmation oc new OrderConfirmation cborder cbhconfirmation ocs add oc RetailPric eListServiet The RetailPriceListServlet responds to requests to reload the price list via the URL loadPriceList It simply creates a new RetailPriceList and a new ShoppingCart Since this servlet would be used by admin
6. Empty Tags One really big difference between XML and HTML is that an XML document is always constrained to be well formed There are several rules that determine when a document is well formed but one of the most important is that every tag has a closing tag So in XML the lt to gt tag is not optional The lt to gt element is never terminated by any tag other than lt to gt Note Another important aspect of a well formed document is that all tags are com pletely nested So you can have lt message gt lt to gt lt to gt lt message gt but never lt message gt lt to gt lt message gt lt to gt A complete list of requirements is con tained in the list of XML Frequently Asked Questions FAQ at 180 UNDERSTANDING XML http www ucc ie xm1 FAQ VALIDWF This FAQ is on the w3c Recommended Reading list at http ww w3 org XML Sometimes though it makes sense to have a tag that stands by itself For exam ple you might want to add a flag tag that marks message as important A tag like that doesn t enclose any content so it s known as an empty tag You can create an empty tag by ending it with gt instead of gt For example the following message contains such a tag lt message to you yourAddress com from me myAddress com subject XML Is Really Cool gt lt flag gt lt text gt How many ways is XML cool Let me count the ways lt text gt lt message gt
7. Further Information 346 Publishing and Disc overing Web Services with J AXR Overview of JAXR Implementing a JAXR Client Running the Client Examples Further Information The Coffee Break Application Coffee Break Overview JAX RPC Distributor Service JAXM Distributor Service Coffee Break Server Deploying and Running the Application Java Encoding Schemes Further Information HTIP Overview HTTP Requests HTTP Responses Glossary 1 22 cess eee anne About the Authors IndeX fii ieee ate eae 347 351 371 382 383 383 385 393 401 415 About This Tutonal Tiss tutorial is a beginner s guide to developing J2EE applications for the Sun Open Networking Environment Sun ONE platform Here we cover all the things you need to know to make the best use of this tutorial Who Should Use This Tutonal This tutorial is intended for programmers interested in developing J2EE applica tions using the Sun ONE platform Specifically it uses the Sun ONE Studio 4 Enterprise Edition for Java to develop J2EE applications and deploy them on Sun ONE Application Server 7 Note This release of the tutorial includes information on Web applications and Web services A future release will add coverage of Enterprise JavaBeans technol ogy and J2EE platform services such as transactions security resources and con nectors This tutorial is not a comprehensive introduction to Sun ONE platform soft
8. SOAPElement price JineItem addChi 1dElement chi 1ldName price addTextNode lib getPriceQ toStringQ total childName envelope createName total SOAPElement total order addChi 1dElement chi ldName total addTextNode orderBean getTotalQ toString With the order complete the application sends the message and closes the con nection URL endpoint new URL url SOAPMessage reply con call msg endpoint con close Because the web xm1 file maps the given endpoint to ConfirmationServ let the application server executes that servlet discussed in Returning the Order Confirmation page 400 to create and return the SOAPMessage object reply Retrieving the Order Confirmation The rest of the placeOrder method retrieves the information returned in reply The client knows what elements are in it because they are specified in con firm dtd After accessing the SOAPBody object the code retrieves the confirmation element and gets the text of the orderID and ship date ele 410 THE COFFEE BREAK APPLICATION ments Finally it constructs and returns a ConfirmationBean with this informa tion SOAPBody sBody reply getSOAPPart getEnvelopeQ getBody Iterator bodyIt sBody getChildElementsQ SOAPBodyElement sbEl CSOAPBodyElement bodyIt nextQ Iterator bodyIt2 sbEl getChildElementsQ SOAPElement ID CSOAPElement bodyIt2 nextQ String id ID getValue SOAPElement sDate SOAPElement
9. System out printIn Couldn t create database ex getMessage Counter counter new Counter context setAttributeC hitCounter counter context log Created hitCounter counter getCounter counter new Counter context setAttributeC orderCounter counter context log Created orderCounter counter getCounter public void contextDestroyed ServletContextEvent event context event getServletContextQ BookDB bookDB context getAttribute bookDB bookDB remove context removeAttributeC bookDB context removeAttributeC hitCounter context removeAttributeC orderCounter Creating a Listener To create a listener in the IDE 1 Mount the Web module as a filesystem 54 JAVA SERVLET TECHNOLOGY 2 Expand the module and WEB INF nodes 3 Right click the classes node and choose New gt JSP amp Servlet Listen ers XxXxXListener where XXX is the type of the listener 4 Type a name for the listener 5 Click Finish Specifying Event Listener Classes To specify an event listener in Web application deployment descriptor using the IDE Mount the Web module as a filesystem Expand the WEB INF node Select the web xml file Select the Deployment tab in the property editor Select the Listeners property and open the property editor Click Add Type the listener class Click OK twice ON DN PWN For an example listener definition see
10. When the JSP page is removed from service the jspDestroy method releases the BookDBAO variable public void jspDestroy bookDBAO null Since the enterprise bean is shared between all the JSP pages it should be initial ized when the application is started instead of in each JSP page Java Servlet technology provides application life cycle events and listener classes for this purpose As an exercise you can move the code that manages the creation of the enterprise bean to a context listener class See Handling Servlet Life Cycle Events page 52 for the context listener that initializes the Java Servlet version of the bookstore application 91 JAVASERVER PAGES TECHNOLOGY Creating Static Content You create static content in a JSP page by simply writing it as if you were creat ing a page that consisted only of that content Static content can be expressed in any text based format such as HTML WML and XML The default format is HTML If you want to use a format other than HTML you include a page direc tive with the contentType attribute set to the format type at the beginning of your JSP page For example if you want a page to contain data expressed in the wireless markup language WML you need to include the following directive lt page contentType text vnd wap wm1 gt A registry of content type names is kept by the IANA at ftp ftp isi edu in notes iana assignments media types Creating Dynamic Content
11. lt Iterator i cart getItems iterator while i hasNextQ ShoppingCartItem item CShoppingCartItem i nextQ BookDetails bd BookDetails item getItemQ gt lt tr gt JSP SCRIPTING ELEMENTS 97 lt td align right bgcolor 4ffffff gt lt i tem getQuantity gt lt td gt lt td bgcolor ffffaa gt lt strong gt lt a href lt request getContextPath gt bookdetai 1s bookId lt bd getBookId gt gt lt bd getTitleQ gt lt a gt lt strong gt lt td gt lt End of while gt The result of executing the page appears in Figure 4 2 Duke s A Bookstore You have 2 items in your shopping cart Figure 4 2 Duke s Bookstore Shopping Cart 98 JAVASERVER PAGES TECHNOLOGY Expressions A JSP expression is used to insert the value of a scripting language expression converted into a string into the data stream returned to the client When the scripting language is the Java programming language an expression is trans formed into a statement that converts the value of the expression into a String object and inserts it into the implicit out object The syntax for an expression is as follows lt scripting language expression gt Note that a semicolon is not allowed within a JSP expression even if the same expression has a semicolon when you use it within a scriptlet The following scriptlet retrieves the number of items in a shopping cart lt Print
12. 286 BUILDING WEB SERVICES WITH JAX RPC call setOperationName new QName BODY_NAMESPACE_VALUE sayHello call addParameter String_1 QNAME_TYPE_STRING ParameterMode IN String params Murphy String result String call invoke params System out printInCresult catch Exception ex ex printStackTrace Building and Running the DilHello Client Because a DII client does not require generated runtime classes the procedures for building and running DITHe11o are simple 1 Make sure youve followed the instructions in Deploying MyHelloService page 276 2 In the Explorer expand the dii package 3 Right click DIIHe11o0 and choose Execute The Output window should display this line Hello Murphy Further Information For more information about JAX RPC and related technologies refer to the fol lowing e Java API for XML based RPC 1 0 Specification http java sun com xml downloads jaxrpc htm e JAX RPC Home http java sun com xm1l jaxrpc index htm e Simple Object Access Protocol SOAP 1 1 W3C Note FURTHER INFORMATION 287 http www w3 org TR SOAP e Web Services Description Language WSDL 1 1 W3C Note http www w3 org TR wsdl To learn more about Sun ONE Studio 4 see the following e Sun ONE Studio 4 Enterprise Edition for Java Tutorial http forte sun com ffj documentation si1s41 slseetut pdf e Building Web Services Sun ONE Studio 4 Programming Seri
13. 3 An information dialog may appear stating that ReceivingServlet java cannot be converted to a servlet Click OK 4 Specify the following context root for the web module in the Context Root field of the WEB INF property window jaxm simple 340 WEB SERVICES MESSAGING WITH JAXM 5 Right click the WEB INF node and choose Deploy from the menu 6 Right click the WEB INF node and choose Execute from the menu If this doesn t work open a web browser and enter the following URL localhost 80 jaxm simple If the page cannot be found make sure the server is running A web page appears with the following text This is a simple example of a round trip JAXM message exchange Click here to send the message If you click the link another page appears with the following text Sent message check sent msg and received reply check reply msg You can find the files sent msg and reply msg in the following directory lt S1AS7_HOME gt domains domain1 server1 config The SAAJ Simple Example The SAAJ Simple application is similar to the Simple example except that it is written using only the SAAJ API In SAAJ Simple the ca11 method takes a Java Object rather than a URLEndpoint object to designate the recipient and thus uses only the javax xml soap package Running this example generates the files sent msg and reply msg which you will find in the server instance config uration directory To deploy and run t
14. SGML only definitions gt common definitions The conditional sections are introduced by lt followed by the INCLUDE or IGNORE keyword and another After that comes the contents of the condi tional section followed by the terminator gt In this case the XML defini tions are included and the SGML definitions are excluded That s fine for XML documents but you can t use the DTD for SGML documents You could change the keywords of course but that only reverses the problem 228 UNDERSTANDING XML The solution is to use references to parameter entities in place of the INCLUDE and IGNORE keywords someExternal dtd lt XML XML only definitions gt lt SGML SGML only definitions gt common definitions Then each document that uses the DTD can set up the appropriate entity defini tions lt DOCTYPE foo SYSTEM someExternal dtd lt ENTITY XML INCLUDE gt lt ENTITY SGML IGNORE gt gt lt foo gt lt foo gt This procedure puts each document in control of the DTD It also replaces the INCLUDE and IGNORE keywords with variable names that more accurately reflect the purpose of the conditional section producing a more readable self docu menting version of the DTD Resolving A Naming Conflict The XML structures you have created thus far have actually encountered a small naming conflict It seems that xhtm l dtd defines a title ele
15. Save this DTD as slideshow3 dtd The next step is to modify the XML file to use the new element name To do that make the changes highlighted below lt slide type all1 gt lt slide title gt Wake up to lt slide title gt lt slide gt lt OVERVIEW gt lt slide type all1 gt lt slide title gt Overview lt slide title gt lt item gt Save a copy of this file as s ideSamp1e09 xml 230 UNDERSTANDING XML Using Namespaces As you saw earlier one way or another it is necessary to resolve the conflict between the title element defined in slideshow dtd and the one defined in xhtm 1 dtd when the same name is used for different purposes In the previous exercise you hyphenated the name in order to put it into a different namespace In this section you ll see how to use the XML namespace stan dard to do the same thing without renaming the element The primary goal of the namespace specification is to let the document author tell the parser which DTD or schema to use when parsing a given element The parser can then consult the appropriate DTD or schema for an element definition Of course it is also important to keep the parser from aborting when a dupli cate definition is found and yet still generate an error if the document refer ences an element like title without qualifying it identifying the DTD or schema to use for the definition Note Namespaces apply to attributes as well as to
16. System out printIn lastPrice catch Exception ex ex printStackTraceQ In order for Request java to be runnable the second argument supplied to the method ca11 has to be a valid existing URI which is not true in this case See the JAXM code in the case study for similar code that you can run JAXM Client page 403 Also the application in the next section is one that you can run The UddiPing Example The sample program UddiPing java is another example of a standalone appli cation A Universal Description Discovery and Integration UDDD service is a business registry and repository from which you can get information about busi 328 WEB SERVICES MESSAGING WITH JAXM nesses that have registered themselves with the registry service For this exam ple the UddiPing application accesses a UDDI test registry to demonstrate a request being sent and a response being received The application prints out the complete message that is returned that is the complete XML document as it looks when it comes over the wire In addition to printing out the entire XML document it also prints out just the text content of the response making it much easier to see the information you want The files for the UddiPing example in the directory lt INSTALL gt j2eetutorial examples jaxm uddiping are uddi properties and UddiPing java You will be modifying the file uddi properties which contains the URL of the destination t
17. TAGS THAT DEFINE SCRIPTING VARIABLES Table 5 4 Scope of Objects Continued Accessible From Lifetime O Current and any future request from licat application the same Web application The life of the application Providing Infomation about the Scripting Variable The last example described in Tags That Define Scripting Variables page 121 defines a scripting variable name that is used for accessing information about the elements in a collection lt tlt iterator name member type org Member group lt dept getMembers gt gt lt tr gt lt td gt lt jsp getProperty name member property name gt lt td gt lt td gt lt jsp getProperty name member property phone gt lt td gt lt td gt lt jsp getProperty name member property emai 1 gt lt td gt lt tr gt lt tit iterator gt When the JSP page containing this tag is translated the Web container generates code to synchronize the scripting variable with the object referenced by the vari able To generate the code the Web container requires certain information about the scripting variable e Variable name e Variable class e Whether the variable refers to a new or existing object e The availability of the variable There are two ways to provide this information by specifying scripting variable properties in the TLD or by defining a tag extra info class and including the tei class element in the TLD Using the variable element is simpler bu
18. ates the MyHelloServiceRPC class file when you choose the Generate Client Proxy menu item The IDE gets the name MyHelloServiceRPC from the WSDL file which was created in Generating the Service s Helper Classes and WSDL File page 275 When the IDE created the WSDL file it constructed the name of the service definition interface by appending RPC to the service name MyHel loService 277 278 BUILDING WEB SERVICES WITH JAX RPC Here is the full source code listing for the StaticStubHel 1o client package staticstub import javax xml rpc Stub import staticstub MyStaticGenClient MyHelloService_Imp1 import staticstub MyStaticGenClient MyHelloServiceRPC public class StaticStubHello public static void main String args try Stub stub createProxyQ MyHelloServiceRPC hello MyHelloServiceRPC stub System out printInChello sayHel lo C Duke System out printIn Chello sayGoodbye Jake catch Exception ex ex printStackTrace private static Stub createProxy Note MyHelloService_Imp1 is implementation specific return Stub Cnew MyHel1oService_Imp C getMyHel 1oServiceRPCPort Building and Running the Static SubHello Client These are the basic steps for building and running the client 1 Create the client New Web Services Web Service Client 2 Generate the client s runtime classes Right click the client node and choose Generate Client Proxy 3 Right clic
19. can put any type of content including XML in an AttachmentPart object And because the SOAP part can contain only XML content you must use an Attach mentPart object for any content that is not in XML format Creating an AttachmentPart Object and Adding Content The SOAPMessage object creates an AttachmentPart object and the message also has to add the attachment to itself after content has been added The SOAP Message class has three methods for creating an AttachmentPart object The first method creates an attachment with no content In this case an Attach mentPart method is used later to add content to the attachment AttachmentPart attachment message createAttachmentPartQ You add content to attachment with the AttachmentPart method setContent This method takes two parameters a Java Object for the content and a String object that gives the content type Content in the SOAPBody part of a message automatically has a Content Type header with the value text xml because the content has to be in XML In contrast the type of content in an AttachmentPart object has to be specified because it can be any type Each AttachmentPart object has one or more headers associated with it When you specify a type to the method setContent that type is used for the header Content Type Content Type is the only header that is required You may set other optional headers such as Content Id and Content Location For conve nience JAXM provid
20. gt lt item gt lt slide gt lt slideshow gt When you echo this file with an XML parser you ll see the following output Diagram frobmorten lt fuznaten lt 3 gt A lt 1 gt lt l gt fozzle V lt 2 gt framboze staten lt 3 gt frenzle lt 2 gt The point here is that the text in the CDATA section will have arrived as it was written Since the parser doesn t treat the angle brackets as XML they don t generate the fatal errors they would otherwise cause Because if the angle brackets weren t in a CDATA section the document would not be well formed Creating a Document Type Defnition DTD After the XML declaration the document prolog can include a DTD which lets you specify the kinds of tags that can be included in your XML document In addition to telling a validating parser which tags are valid and in what arrange ments a DTD tells both validating and nonvalidating parsers where text is CREATING A DOCUMENT TYPE DEFINITION DTD expected which lets the parser determine whether the whitespace it sees is sig nificant or ignorable Basic DID Definitions To begin learning about DTD definitions let s start by telling the parser where text is expected and where any text other than whitespace would be an error Whitespace in such locations is ignorable Note The DTD defined in this section is contained in slideshowla dtd The browsable
21. indicates that the request requires HTTP authentication 500 indicates an error inside the HTTP server which prevented it from fulfilling the request 503 indicates that the HTTP server is temporarily overloaded and unable to handle the request Glossary ABCDEFGHIJKLMNOPQRSTUVWXYZ access control The methods by which interactions with resources are limited to collections of users or programs for the purpose of enforcing integrity confidentiality or availability constraints ACID The acronym for the four properties guaranteed by transactions atomicity consistency isolation and durability anonymous access Accessing a resource without authentication Ant A Java based and thus cross platform build tool that can be extended using Java classes The configuration files are XML based calling out a target tree where various tasks get executed applet A component that typically executes in a Web browser but can execute in a variety of other applications or devices that support the applet programming model Application Deployment Tool A tool for creating WAR files for application deployment and handling secu rity issues archiving Saving the state of an object and restoring it attribute A qualifier on an XML tag that provides additional information 429 430 authentication The process that verifies the identity of a user device or other entity in a computer system usually as a prerequisite to allowi
22. org addServices services Then it saves the organization to the registry Collection orgs new ArrayListQ orgs add org BulkResponse response blcm saveOrganizations orgs The BulkResponse object returned by saveOrganizations includes the Key object containing the unique key value for the organization The executePub lish method first checks to make sure the saveOrgani zations call succeeded DELETING THE SERVICE FROM THE REGISTRY If the call succeeded the method extracts the value from the Key object and dis plays it Collection keys response getCollection Iterator keyIter keys iteratorQ if keyIter hasNextQ javax xml registry infomodel Key orgKey javax xml registry infomodel Key keyIter nextQ id orgKey getIdQ System out printInC Organization key is id Finally the method returns the string id so that the OrgPublisher program can save it in a file for use by the OrgRemover program Deleting the Service From the Registry The OrgRemover program deletes the service from the Registry Server immedi ately before the service is removed Like the OrgPublisher program the OrgRemover program starts by fetching values from the CoffeeRegistry prop erties file One these values keyFile is the name of the file that contains the key that uniquely identifies the service OrgPublisher reads the key from the file connects to the Registry Server by invoking makeConnection and then deletes the se
23. pageContext APPLICATION_SCOPE if screens null pageContext setAttribute screens new HashMap pageContext APPLICATION_SCOPE return EVAL_BODY_INCLUDE i The table of screen definitions is filled in by ScreenTag and ParameterTag from text provided as attributes to these tags Table 5 6 shows the contents of the screen definitions hash table for the Duke s Bookstore application Table 5 6 Screen Definitions enter Duke s Bookstore banner j bookstore jsp catalog Book Catalog banner j catalog jsp bookdetails Book Description banner j bookdetails jsp showcart Shopping Cart banner j showcart jsp cashier Cashier banner j cashier jsp receipt Receipt banner j receipt jsp In doEndTag DefinitionTag creates a public object of class Definition selects a screen definition from the screens object based on the URL passed in the request and uses it to initialize the Definition object public int doEndTag throws JspTagException try Definition definition new Definition HashMap screens null ArrayList params null TagSupport screen null screens HashMap pageContext getAttribute screens pageContext APPLICATION_SCOPE if screens null params ArrayList screens get screenId A TEMPLATE TAG LIBRARY 145 else if params null Iterator ir null if params null ir params iterator while Cir null amp amp ir hasNextQ
24. rizes these functional areas subfunctions in each area tags in each subfunction and the prefixes used in the Duke s Bookstore application Table 6 1 JSTL Tags catch out remove set Expression Language Support choose when otherwise forEach forTokens if Flow Control import param redirect param url param URL Management out parse set choose when Flow Control otherwise forEach if transform param Transformation EXPRESSION LANGUAGE SUPPORT Table 6 1 JSTL Tags Continued Locale setLocale bundle message param setBundle Message formatting formatNumber formatDate Number and date parseDate formatting parseNumber setTimeZone timeZone setDataSource query dateParam Database param transaction update dateParam param The URIs used to access the libraries are e Core http java sun com jstl core e XML http java sun com jst1 xml1 e Internationalization http java sun com jstl fmt e SQL http java sun com jstl sql The JSTL tag libraries comes in two versions see Twin Libraries page 154 The URIs for the JSTL EL library are as shown above The URIs for the JSTL RT library are named append _rt to the end Expression Language Support A primary feature of JSTL is its support for an expression language EL An expression language in concert with JSTL tags makes it possible to easily access application data and manipula
25. Because these classes are referenced in the client s source code they must be generated before the client is com piled See the section StaticStubHello Source Code page 277 7 Right click Stati cStubHel1o and choose Execute The IDE compiles and runs the program The Output window should dis play these lines Hello Duke Goodby Jake In this example you ve run the StaticStubHel1o client from within the IDE which can locate the runtime classes with its default classpath If you were to run the client outside of the IDE you d want to create a JAR file containing the runtime classes of the MyStaticGenClient package 280 BUILDING WEB SERVICES WITH JAX RPC Dynamic Proxy Client Example The client in the preceding section used a static stub for the proxy In contrast the client example in this section Dynami cProxyHel lo calls a remote procedure through a dynamic proxy an object created at runtime that represents the Web service Although the source code for the StaticStubHelloClient example relied on an implementation specific class but the DynamicProxyHello code does not have this limitation However the Dynami cProxyHel 1o client does rely on implementation specific runtime classes that are generated by the IDE Dynamic ProxyHello Source Code The Dynami cProxyHel1o program constructs the dynamic proxy as follows 1 Creates a Service object named helloService Service helloService serviceFactory createSer
26. HTIP SOAP Transport Protocol Client requests and Web service responses are transmitted as Simple Object Access Protocol SOAP messages over HTTP to enable a completely interoper able exchange between clients and Web services all running on different plat forms and at various locations on the Internet HTTP is a familiar request and response standard for sending messages over the Internet and SOAP is an XML based protocol that follows the HTTP request and response model The SOAP portion of a transported message handles the following e Defines an XML based envelope to describe what is in the message and how to process the message e Includes XML based encoding rules to express instances of application defined data types within the message e Defines an XML based convention for representing the request to the remote service and the resulting response WSDL Standard Fommat The Web Services Description Language WSDL is a standardized XML format for describing network services The description includes the name of the ser vice the location of the service and how to communicate with the service WSDLs can be stored in UDDI registries and or published on the Web The J2EE platform provides a tool for generating the WSDL for a Web service that uses remote procedure calls to communicate with clients UDDI AND EBXML STANDARD FORMATS UDDI and ebXML Standard Fomats Other XML based standards such as Universal Description Discovery
27. IMPLIED author CDATA unknown gt lt ELEMENT slide title item gt DEFINING ATTRIBUTES AND ENTITIES IN THE DTD The DTD tag ATTLIST begins the series of attribute definitions The name that follows ATTLIST specifies the element for which the attributes are being defined In this case the element is the s1ideshow element Note once again the lack of hierarchy in DTD specifications Each attribute is defined by a series of three space separated values Commas and other separators are not allowed so formatting the definitions as shown above is helpful for readability The first element in each line is the name of the attribute title date or author in this case The second element indicates the type of the data CDATA is character data unparsed data once again in which a left angle bracket lt will never be construed as part of an XML tag Table 7 3 presents the valid choices for the attribute type Table 7 3 Attribute Types valuel value2 A list of values separated by vertical bars Example below CDATA Unparsed character data For normal people a text string ID A name that no other ID attribute shares IDREF A reference to an ID defined elsewhere in the document IDREFS A space separated list containing one or more ID references ENTITY The name of an entity defined in the DTD ENTITIES A space separated list of entities A valid XML name composed of letters numbers
28. Note The DTD specifications shown here are contained in slideshow2 dtd and xhtm1 dtd The XML file that references it is s1ideSamp1eQ8 xm1 The browsable versions are slideshow2 dtd htm and slideSamp1e08 xm1 htm1 Open your DTD file for the slide presentation and add the text highlighted below to define a parameter entity that references an external DTD file lt ELEMENT slide Cimage title item gt lt ATTLIST slide gt lt ENTITY xhtml SYSTEM xhtml dtd gt xhtml lt ELEMENT title Here you used an lt ENTITY gt tag to define a parameter entity just as for a gen eral entity but using a somewhat different syntax You included a percent sign 225 226 UNDERSTANDING XML before the entity name when you defined the entity and you used the percent sign instead of an ampersand when you referenced it Also note that there are always two steps for using a parameter entity The first is to define the entity name The second is to reference the entity name which actually does the work of including the external definitions in the current DTD Since the URI for an external entity could contain slashes or other characters that are not valid in an XML name the definition step allows a valid XML name to be associated with an actual document This same technique is used in the definition of namespaces and anywhere else that XML constructs need to refer ence external documents Notes e
29. Property Name and Description Default Value javax xml registry queryManagerURL Specifies the URL of the query manager service within the tar get registry provider javax xml registry 1ifeCycleManagerURL Same as the speci fied queryMan Specifies the URL of the life cycle manager service within the agerURL value target registry provider for registry updates javax xml registry semanticEquivalences Specifies semantic equivalences of concepts as one or more tuples of the ID values of two equivalent concepts separated by a comma the tuples are separated by vertical bars jid1 id2 id3 id4 353 354 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR Table 11 1 Standard JAXR Connection Properties Property Name and Description Default Value javax xml registry security authentication None Method UDDI_GET_AUTHT OKEN is the only Provides a hint to the JAXR provider on the authentication supported value method to be used for authenticating with the registry provider javax xml registry uddi maxRows The maximum number of rows to be returned by find opera Integer tions Specific to UDDI providers javax xml registry postalAddressScheme The ID of a Classi ficationScheme to be used as the default postal address scheme See Specifying Postal Addresses page 369 for an example Table 11 2 Implementation Specific JAXR Connection Properties Property Name and Description Default Value com
30. The conversion process between the constants and runtime expressions and attribute types follows the rules described for JavaBeans component properties in Setting JavaBeans Component Properties page 106 The attributes of the Struts logic present tag determine whether the body of the tag is evaluated In the following example an attribute specifies a request parameter named Clear lt logic present parameter Clear gt The Duke s Bookstore application page catalog jsp uses a runtime expression to set the value of the attribute that determines the collection of books over which the Struts logic iterate tag iterates lt logic iterate collection lt bookDB getBooks gt jid book type database BookDetails gt Tags with Bodies A custom tag can contain custom and core tags scripting elements HTML text and tag dependent body content between the start and end tag In the following example the Duke s Bookstore application page showcart jsp uses the Struts logic present tag to clear the shopping cart and print a message if the request contains a parameter named Clear lt logic present parameter Clear gt lt cart clearQ gt lt font color ff0000 size 2 gt lt strong gt You just cleared your shopping cart lt strong gt lt br gt amp nbsp lt br gt lt font gt lt logic present gt TYPES OF TAGS Choosing between Passing Information as Attributes or Body As shown in the last two sections
31. The messaging provider that receives the message will forward it to the intended destination and return the response if any at a later time The interval between sending a request and getting the response may be very short or it may be measured in days In this style of messaging the original message is sent as a one way message and any response is sent subsequently as a one way message Not surprisingly this style of messaging is referred to as one way mes saging 297 298 WEB SERVICES MESSAGING WITH JAXM st and ain a One way Figure 10 3 Request response and One way Messaging Messaging Providers A messaging provider is a service that handles the transmission and routing of messages It works behind the scenes to keep track of messages and see that they are sent to the proper destination or destinations Transparency One of the great features of a messaging provider is that you are not even aware of it You just write your JAXM application and the right things happen For example when you are using a messaging provider and send a message by call ing the ProviderConnection send method the messaging provider receives the message and works with other parts of the communications infrastructure to per form various tasks depending on what the message s header contains and how the messaging provider itself has been implemented The message arrives at its final destination without your even knowing about the details in
32. Thus to define the Duke s Bookstore data source you first need to define a data pool as follows 1 In the IDE select the Runtime tab of the Explorer 2 Expand the nodes Server Registry Installed Servers Sun ONE Applica tion Server 7 localhost 4848 3 Right click Unregistered JDBC Connection Pools and select Add New JDBC Data Pool 4 Type com pointbase jdbc jdbcDataSource for the DataSource Class name 5 Type bookstore pool for the Name 6 Click Properties and open the property editor 7 Add the properties and values listed in Table 2 1 Table 2 1 Bookstore Pool Properties DatabaseName jdbc pointbase server localhost sun appserv samples User BOOKSTORE Password BOOKSTORE 8 Right click the bookstore pool data pool and choose Register 9 Select the application server that you want the pool to be registered in and click Register 10 Click OK 11 Expand the Registered JDBC Connection Pools node and notice that bookstore pool is listed Then create the data source as follows 1 In the IDE select the Runtime tab of the Explorer 43 44 INTRODUCTION TO WEB APPLICATIONS 2 Expand the nodes Server Registry Installed Servers Sun ONE Applica tion Server 7 localhost 4848 3 Right click Unregistered JDBC Data Sources and select Add a new JDBC Data Source Type jdbc BookDB for the JNDI Name Choose bookstore pool for the Pool Name Right click the jdbc BookDB data
33. Who Should Use This Tutorial Vii Prerequisites viii How to Read This Tutorial viii About the Examples ix Further Information x How to Print This Tutorial xi Typographical Conventions xi OVvervieW io 6d bool eo hh eh oe a ee a ee ne od L Web Services Support Distributed Multitiered Applications 5 J2EE Containers 11 Packaging 13 Development Roles 14 J2EE APIs 17 Intoduction to Web Applications 25 Web Application Life Cycle 26 Web Modules 28 Configuring Web Modules 30 Deploying Web Modules 33 Listing Deployed Web Modules 34 Running Web Applications 34 Updating Web Modules 35 Undeploying Web Modules 36 Duke s Bookstore 37 Internationalizing and Localizing Web Applications 38 Accessing Databases from Web Applications 39 iii Chapter 3 Chapter 4 Chapter 5 CONTENTS Further Information 45 Java Servlet Technology 0 000es00022 47 What is a Servlet 47 The Example Servlets 48 Servlet Life Cycle 51 Sharing Information 54 Initializing a Servlet 58 Writing Service Methods 59 Filtering Requests and Responses 64 Invoking Other Web Resources 72 Accessing the Web Context 75 Maintaining Client State 76 Finalizing a Servlet 79 Further Information 82 JavaServer Pages Technology 83 What Is a JSP Page 83 The Example JSP Pages 86 The Life Cycle of a JSP Page 88 Initializing and Finalizing a JSP Page 91 Creating Static Content 92 Creating Dynamic Content 92 Including Conten
34. You create dynamic content by accessing Java programming language objects from within scripting elements Using Objects within J SP Pages You can access a variety of objects including enterprise beans and JavaBeans components within a JSP page JSP technology automatically makes some objects available and you can also create and access application specific objects Implicit Objects Implicit objects are created by the Web container and contain information related to a particular request page or application Many of the objects are defined by USING OBJECTS WITHIN JSP PAGES 93 the Java Servlet technology underlying JSP technology and are discussed at length in Chapter 3 Table 4 2 summarizes the implicit objects Table 4 2 Implicit Objects Class Description application javax servilet ServletContext The context for the JSP page s servlet and any Web components contained in the same application See Accessing the Web Context page 75 config javax servilet ServletConfig Initialization information for the JSP page s servlet exception java lang Throwable Accessible only from an error page See Handling Errors page 90 javax servilet jsp JspWriter The output stream java lang Object The instance of the JSP page s servlet processing the current request Not typically used by JSP page authors pageContext javax servilet jsp PageContext The context for the JSP
35. and whose content is written according to the scripting language used in the JSP page The JSP specification describes the syntax and semantics for the case where the language page attribute is java JSP scriptlet A JSP scripting element containing any code fragment that is valid in the scripting language used in the JSP page The JSP specification describes what is a valid scriptlet for the case where the language page attribute is java JSP tag A piece of text between a left angle bracket and a right angle bracket that is used in a JSP file as part of a JSP element The tag is distinguishable as markup as opposed to data because it is surrounded by angle brackets 442 JSP tag library A collection of custom tags identifying custom actions described via a tag library descriptor and Java classes JTA See Java Transaction API ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFGHIJKLMNOPQRSTUVWXYZ life cycle The framework events of a component s existence Each type of component has defining events which mark its transition into states where it has varying availability for use For example a servlet is created and has its init method called by its container prior to invocation of its service method by clients or other servlets who require its functionality After the call of its init method it has the data and readiness for its intended use The servlet s destroy method is called by its container prior to the ending of its existence so
36. definition setParam Parameter ir nextQ put the definition in the page context pageContext setAttribute definitionName definition catch Exception ex ex printStackTrace return EVAL_PAGE If the URL passed in the request is enter the Definition contains the items shown in Table 5 7 Table 5 7 Definition for the URL enter Duke s Bookstore banner jsp bookstore jsp The screen definition for the URL enter is shown in Table 5 8 The definition specifies that the value of the Title parameter Duke s Bookstore should be inserted directly into the output stream but the values of Banner and Body should be dynamically included Table 5 8 Screen Definition for the URL enter Parameter Name Parameter Value isDirect title Duke s Bookstore banner banner jsp body bookstore jsp 146 CUSTOM TAGS IN JSP PAGES InsertTag uses Definition to insert parameters of the screen definition into the response In the doStartTag method it retrieves the definition object from the page context public int doStartTag get the definition from the page context definition Definition pageContext getAttribute definitionName get the parameter if parameterName null amp amp definition null parameter Parameter definition getParam parameterName if parameter null directInclude parameter isDirectQ return SKIP_BODY The doEndTag method inserts the p
37. fault getDetailQ if C detail null Iterator it detail getDetailEntriesQ while it hasNextQ entry DetailEntry it nextQ String value entry getValueQ System out printIn Detail entry value catch Exception ex ex printStackTraceQ Compiling and Running SOAPFaultlestjava To compile and run SoapFaultTest first make sure you followed the instruc tions in Setting the Classpath page 324 Then perform the following steps 1 Mount the following filesystem lt INSTALL gt j2eetutorial examples jaxm fault 2 Right click the SoapFaultTest file in the Filesystems tab and choose the Execute menu item The program output window displays the response message as follows the SOAP message is all on one line Here is what the XML message looks like lt xml version 1 0 encoding UTF 8 gt lt soap env Envelope xmlns soap env http schemas xmlsoap org soap enve lope gt lt soap env Header gt lt soap env Body gt lt soap env Fault gt lt faultcode gt Client lt faultcode gt lt faultstring gt Message does not have necessary info lt faultstring gt lt faultactor gt http gizmos com order lt faultactor gt lt detai 1 gt lt PO order xmIns PO http gizmos com orders gt quantity element does not have a value lt PO order gt lt PO confirmation xmIns PO http gizmos com confirm gt Incomplete address no STARTING THE APPLICATION SERVER zip code lt PO confirmati
38. jsp include cannot access resources that reside outside of the Web application and causes unneces sary buffering when the resource included is used by another element In the example below the transform element uses the content of the included resource as the input of its transformation The jsp include element reads the content of the response writes it to the body content of the enclosing transform element which then re reads the exact same content It would be more efficient if the transform element could access the input source directly and avoid the buffering involved in the body content of the transform tag lt acme transform gt lt jsp include page exec employeesList gt lt acme transform gt The import tag is therefore the simple generic way to access URL based resources whose content can then be included and or processed within the JSP page For example in XML Tags page 165 import is used to read in the XML document containing book information and assign the content to the scoped vari able xm1 lt c import url books xm1 var xm1 gt lt xiparse xml xml var booklist scope application gt The param tag analogous to the jsp param tag see jsp param Element page 100 can be used with import to specify request parameters In Session Tracking page 78 we discussed how an application must rewrite URLs to enable session tracking whenever the client turns off cookies You can use the url tag to rew
39. lt page errorPage errorpage jsp gt The beginning of errorpage jsp indicates that it is serving as an error page with the following page directive lt page isErrorPage true false gt This directive makes the exception object of type javax servlet jsp JspEx ception available to the error page so that you can retrieve interpret and pos sibly display information about the cause of the exception in the error page INITIALIZING AND FINALIZING A JSP PAGE Note You can also define error pages for the WAR that contains a JSP page If error pages are defined for both the WAR and a JSP page the JSP page s error page takes precedence Inttalizing and Finalizing a J SP Page You can customize the initialization process to allow the JSP page to read persis tent configuration data initialize resources and perform any other one time activities by overriding the jspInit method of the JspPage interface You release resources using the jspDestroy method The methods are defined using JSP declarations discussed in Declarations page 95 The bookstore example page initdestroy jsp defines the jspInit method to retrieve the object database BookDBAO that accesses the bookstore database and stores a reference to the bean in bookDBAO private BookDBAO bookDBAO public void jspInit bookDBAO BookDBAO getServletContextQ getAttribute bookDB if CbookDBAO null System out printInC Couldn t get database
40. method both creates headerElement and adds it to header CLIENT WITH A MESSAGING PROVIDER Now that you have identified headerElement with headerName and added it to header the next step is to add content to headerElement which the next line of code does with the method addTextNode headerElement addTextNodeC order Now you have the SOAPHeader object header that contains a SOAPHeaderEle ment object whose content is order Adding Contentto the SOAP Body The process for adding content to the SOAPBody object is the same for clients using a messaging provider as it is for standalone clients This is also the same as the process for adding content to the SOAPHeader object You access the SOAP Body object add a SOAPBodyElement object to it and add text to the SOAP BodyElement object It is possible to add additional SOAPBodyElement objects and it is possible to add subelements to the SOAPBodyElement objects with the method addChildElement For each element or child element you add content with the method addTextNode The section on the standalone client demonstrated adding one SOAPBodyElement object adding a child element and giving it some text The following example shows adding more than one SOAPBodyElement and adding text to each of them The code first creates the SOAPBodyElement object purchaseLineItems which has a fully qualified namespace associated with it That is the Name object for it has a local name a namespace
41. new HashSet creds add passwdAuth connection setCredentials creds It then creates an Organization object with the name JAXRPCCoffeeDistribu tor then a User object that will serve as the primary contact It gets the data PUBLISHING THE SERVICE IN THE REGISTRY 389 from the resource bundle instead of hardcoding it as strings but otherwise this code is almost identical to that shown in the JAXR chapter ResourceBundle bundle ResourceBundle getBundle jaxrpc registry CoffeeRegistry Create organization name and description Organization org blcm createOrganization bundle getStringC org name InternationalString s blcm createInternationalString Cbundle getStringC org description org setDescription s Create primary contact set name User primaryContact blcm createUser PersonName pName blcm createPersonName bundle getStringC person name primaryContact setPersonName pName It adds a telephone number and email address for the user then makes the user the primary contact org setPrimaryContact primaryContact It gives JAXRPCCoffeeDistributor a classification using the North American Industry Classification System NAICS In this case it uses the classification Other Grocery and Related Products Wholesalers Classification classification Classification blcm createClassification cScheme bundle getString classification name bundle getString classification val
42. passed in as String You can set these properties as follows e Most of these properties must be set as connection properties in a JAXR client program For example Properties props new Properties props setProperty javax xml registry queryManagerURL http uddi ibm com testregistry inquiryapi props setProperty javax xml registry 1lifeCycleManagerURL https uddi ibm com testregistry protect publishapi ConnectionFactory factory ConnectionFactory newInstanceQ factory setProperties props connection factory createConnection e The postalAddressScheme useCache and useSOAP properties may be set as system properties in the client program 356 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR An additional system property specific to the implementation of JAXR in the Sun ONE Application Server is com sun xml registry userTaxonomyFi le names For details on using this property see Defining a Taxonomy page 366 Obtaining and Using a RegistryService Object After creating the connection the client uses the connection to obtain a Regis tryService object and then the interface or interfaces it will use RegistryService rs connection getRegistryService BusinessQueryManager bqm rs getBusinessQueryManager BusinessLifeCycleManager blcm rs getBusinessLifeCycleManager Typically a client obtains both a BusinessQueryManager object and a Busi nessLifeCycleManager object fro
43. war Web application distributable A Web application that uses Java WSDP technology written so that it can be deployed in a Web container distributed across multiple Java virtual machines running on the same host or different hosts The deployment descriptor for such an application uses the distributable element Web component A component that provides services in response to requests either a servlet or a JSP page Web container A container that implements the Web component contract of the J2EE archi tecture This contract specifies a runtime environment for Web components that includes security concurrency life cycle management transaction 453 deployment and other services A Web container provides the same services as a JSP container and a federated view of the J2EE platform APIs A Web container is provided by a Web server Web container distributed A Web container that can run a Web application that is tagged as distribut able and that executes across multiple Java virtual machines running on the same host or on different hosts Web module A unit that consists of one or more Web components other resources and a Web deployment descriptor Web resource A static or dynamic object contained in a Web application archive that can be referenced by a URL Web resource collection A list of URL patterns and HTTP methods that describe a set of resources to be protected Web server Software that provides services to a
44. you ll see that the URL is written to the service s WSDL file The SOAP RPC URL property has the following syntax http lt host gt lt port gt lt web context gt lt url pattern gt The lt host gt is the name of the computer that is running the Web server and lt port gt is the server s port number The lt web context gt sometimes called the context root is a name that is mapped to the document root of the servlet that implements the Web service The lt url pattern gt is an arbitrary string which may contain forward slashes for example my app account The lt url pattern gt allows you to further qualify the URL By default the IDE assigns the name of the Web service MyHel loService to the lt web context gt and lt url pattern gt elements 2 For the SOAP RPC URL property make sure that the port number matches the value you noted in Verifying the IDE Settings page 273 If the host name is localhost and the port number is 80 then the SOAP RPC URL property should be http localhost 80 MyHel loService MyHel loService 3 If necessary change the port number of the SOAP RPC URL 4 Close the Properties sheet Generating the Service s Helper Classes and WSDL Fle 1 Right click the MyHelloService Web service and choose Generate Web Service The IDE creates the service s helper classes placing them in the MyHel loServiceGen package and also creates the MyHelloService WSDL file 276 BUILDING WEB
45. 1 online help e Building J2EE Applications http forte sun com ffj documenta tion s1s41 j2eeapps pdf e Building Web Components http forte sun com ffj documenta tion s1s41 webcomp pdf e Building Web Services http forte sun com ffj documenta tion s1s41 websrvcs pdf e For complete documentation for Sun ONE Studio 4 go to http wwws sun com software sundev jde documenta tion index html HOW TO PRINT THIS TUTORIAL xi How to Print This Tutonal To print this tutorial follow these steps 1 Ensure that Adobe Acrobat Reader is installed on your system 2 Open the PDF version of this book 3 Click the printer icon in Adobe Acrobat Reader Typographical Conventions Table P 2 lists the typographical conventions used in this tutorial Table P 2 Typographical Conventions italic Emphasis titles first occurrence of terms URLs code examples file names command monospace i names programming language keywords italic monospace Variable file names Menu selections indicated with the right arrow character gt for example First Second should be interpreted as select the First menu then choose Sec ond from the First submenu l Overview Monica Pawlan Tonay more and more developers want to write distributed transactional applications for the enterprise and leverage the speed security and reliability of server side technology If you are already working in this area you know
46. 258 point to point 258 296 303 setting properties 352 to the messaging provider 258 connection factory JAXR creating 352 Connection interface 349 352 connection properties com sun xml registry ht tp proxyHost 354 com sun xml registry ht tp proxyPort 354 com sun xml registry ht tps proxyHost 354 com sun xml registry ht tps proxyPassword 355 com sun xml registry ht tps proxyPort 354 com sun xml registry ht tps proxyUserName 355 com sun xml registry use SOAP 355 examples 352 javax xml registry 1lifeCy cleManagerURL 353 javax xml registry postal AddressScheme 354 370 javax xml registry query ManagerURL 353 javax xml registry securi ty authentication Method 354 javax xml registry seman INDEX 461 ticEquivalences 353 370 javax xml registry ud di maxRows 354 ConnectionFactory class 352 connectors See J2EE Connector technolo gy container 250 containers 11 See also applet containers EJB containers J2EE application clients containers Web containers services 12 context roots 30 country codes ISO 3166 357 createAttachmentPart method 318 createClassification method 363 367 createClassificationScheme method 367 createExternalLink method 367 createOrganization method 362 createPostalAddress method 371 createService method 364 createServiceBinding method 364 custom tags 111 attributes 120 validation 129 bodies 120 cooperating 121 defining 122 462 INDEX examples 142 scripting
47. All JAXM connections are created by a connection factory In the case of a SOAPCon nection object the factory is a SOAPConnectionFactory object A client obtains the default implementation for SOAPConnectionFactory by calling the following line of code SOAPConnectionFactory factory SOAPConnectionFactory newlInstance The client can use factory to create a SOAPConnection object SOAPConnection con factory createConnection Getting a Connection to the Messaging Provider In order to use a messaging provider an application must obtain a ProviderCon nection object which is a connection to the messaging provider rather than to a specified recipient There are two ways to get a ProviderConnection object the first being similar to the way a standalone client gets a SOAPConnection object This way involves obtaining an instance of the default implementation for Pro viderConnectionFactory which is then used to create the connection ProviderConnectionFactory pcFactory ProviderConnectionFactory newInstance ProviderConnection pcCon pcFactory createConnection The variable pcCon represents a connection to the default implementation of a JAXM messaging provider The second way to create a ProviderConnection object is to retrieve a Pro viderConnectionFactory object that is implemented to create connections to a specific messaging provider The following code demonstrates getting such a CREATING A MESSAGE ProviderC
48. An Organization object is one of the more complex data items in the JAXR API It normally includes the following e A Name object e A Description object e A Key object representing the ID by which the organization is known to the registry This key is created by the registry not by the user and is returned after the organization is submitted to the registry e A PrimaryContact object which is a User object that refers to an autho rized user of the registry A User object normally includes a PersonName 361 362 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR object and collections of TelephoneNumber EmailAddress and or Post alAddress objects e A collection of Classification objects e Service objects and their associated ServiceBinding objects For example the following code fragment creates an organization and specifies its name description and primary contact When a client creates an organiza tion it does not include a key the registry returns the new key when it accepts the newly created organization The blcm object in this code fragment is the BusinessLifeCycleManager object returned in Obtaining and Using a Registry Service Object page 356 An InternationalString object is used for string values that may need to be localized Create organization name and description Organization org blcm createOrganization The Coffee Break InternationalString s blcm createInternationalStringC Purveyor of
49. BookDetailsServlet generates an HTML page that dis plays information about a book that the servlet retrieves from a database The servlet first sets response headers the content type of the response and the buffer size The servlet buffers the page content because the database access can gener ate an exception that would cause forwarding to an error page By buffering the response the client will not see a concatenation of part of a Duke s Bookstore page with the error page should an error occur The doGet method then retrieves a PrintWriter from the response CONSTRUCTING RESPONSES 63 For filling in the response the servlet first dispatches the request to BannerServ let which generates a common banner for all the servlets in the application process is discussed in Including Other Resources in the Response page 72 Then the servlet retrieves the book identifier from a request parameter and uses the identifier to retrieve information about the book from the bookstore database Finally the servlet generates HTML markup that describes the book information and commits the response to the client by calling the close method on the PrintWriter public class BookDetailsServlet extends HttpServlet public void doGet HttpServletRequest request HttpServletResponse response throws ServletException IOException set headers before accessing the Writer response setContentType text htm1 response setBufferSize 8192 PrintWrite
50. Break server right click the WEB INF directory of lt INSTALL gt j2eetutorial examples cb cbservice and choose Deploy Running the Coffee Break Client After you have deployed all the Web applications check that all the applica tions SupplierService jaxm coffee supplier cbservice are running by viewing the deployed Web applications with the IDE or the application server administration tool You may need to add lt S1AS7_HOME gt share 1ib xercesImp1 jar to the appli cation server classpath suffix and restart the application server using the applica tion server administration tool To do so 1 Open the URL http localhost 4848 in a browser 2 Select the server node 3 Select the JVM Settings tab 4 Click the Path Settings link RUNNING THE COFFEE BREAK CLIENT 423 5 Add lt S1AS7_HOME gt share 1lib xercesImp1 jar to the Classpath Suffix text area 6 Click Save 7 Click the General tab 8 Stop and restart the server To run the Coffee Break client open the Coffee Break server URL in a Web browser http localhost 80 cbservice orderForm You should see a page something like the one shown in Figure 12 2 Coffee Break Netscape tp localhost 8080 cbserver orderForm gi al Coffee Break Enter the amount of coffee and click Update to update the totals Click Checkout to proceed with your order Figure 12 2 Order Form 424 THE COFFEE BREAK APPLICATION After you have gone through the applica
51. CLIENTS J 2EE Clients A J2EE client can be a Web client or an application client Web Clients A Web client consists of two parts dynamic Web pages containing various types of markup language HTML XML and so on which are generated by Web components running in the Web tier and a Web browser which renders the pages received from the server A Web client is sometimes called a thin client Thin clients usually do not do things like query databases execute complex business rules or connect to legacy applications When you use a thin client heavyweight operations like these are off loaded to enterprise beans executing on the J2EE server where they can leverage the security speed services and reliability of J2EE server side technol ogies Applets A Web page received from the Web tier can include an embedded applet An applet is a small client application written in the Java programming language that executes in the Java virtual machine installed in the Web browser However client systems will likely need the Java Plug in and possibly a security policy file in order for the applet to successfully execute in the Web browser Web components are the preferred API for creating a Web client program because no plug ins or security policy files are needed on the client systems Also Web components enable cleaner and more modular application design because they provide a way to separate applications programming from Web page design Pe
52. Example page 377 to delete the organization you published Deleting a Classification Scheme You may or may not want to delete the classification scheme you published For a UDDI registry deleting a classification scheme removes it from the registry logically but not physically You can no longer use the classification scheme but it will still be visible if for example you call the method QueryMan GETTING A LIST OF YOUR REGISTRY OBJECTS ager getRegisteredObjects Since the public registries allow you to own up to 10 of these objects this is not likely to be a problem However once you have created a classification scheme for postal addresses in a public registry you may want to leave it there for future use The Sun ONE Studio internal UDDI Server Registry imposes no limit on the number of classification schemes you can own To delete the classification scheme you published after you have finished using it run the JAXRDeleteScheme program as follows 1 Click the Running tab in the main window 2 In the Output window tab for either the JAXRSaveClassification Scheme JAXRPublishPostal or JAXRQueryPostal example select the value of the UUID string from the program output Right click in the win dow and choose the Copy menu item Click the JAXRDeleteScheme file in the Filesystems tab In the property window for the file choose the Execution tab Click Arguments Paste the UUID string you copied in step 2 into th
53. Expand the UDDI Server Registry node 3 Right click the Internal UDDI Registry node and choose the Start Server menu item Setting the Compilation Classpath Before you can compile the programs you need to set the compilation classpath To do so 1 Choose Options from the Tools menu 2 Expand the Building node then the Compiler Types node 3 Choose External Compilation 4 Select the Expert tab 5 Click the Class Path property then double click the ellipsis in the value field 6 In the property editor click Add JAR Zip 7 In the file chooser navigate to the directory lt S1STUDIO_HOME gt jwsdp common lib and choose the jaxr api jar file This file is also in lt S1AS7_HOME gt share 1ib 8 Click OK 9 Click OK in the property editor then click Close in the Options window 375 376 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR Compiling the Examples To compile the programs 1 In the Filesystems tab of the Explorer right click the lt INSTALL gt j2eetutorial examples jaxr directory 2 Choose the Compile All menu item Compiler messages appear in an output window Running the J AXRPublish Example To run the JAXRPublish program right click the file in the Filesystems tab and choose the Execute menu item The program output appears in an output window associated with the Running tab of the main window It displays the string value of the key of the new organi zation which is named Th
54. Installed Servers b Verify that the Sun One Application Server 7 is listed below Installed Servers If it is not listed then follow the instructions in Deploying Web Modules page 33 e The Sun ONE Application Server 7 is the default server a In the Runtime pane of the Explorer expand Server Registry Default Servers b Verify that beneath Default Servers there is a node for Web Tier Appli cations serverl1 host port c If this node is not displayed then follow the instructions in the Sun ONE Studio 4 Enterprise Edition for Java Tutorial e You know the server instance port number a Start the Admin Console of the Sun ONE Application Server 7 b in the console s left pane select Domains c In the tree of the left pane expand the App Server Instances node and choose server 274 BUILDING WEB SERVICES WITH JAX RPC d Note the HTTP Port number in the right pane In most installations the default port number is 80 In a later section Specifying the SOAP RPC URL page 275 you will specify this number for MyHe11loService Creating MyHelloService 1 In the IDE mount the file system at lt INSTALL gt examples jaxrpc 2 In the Explorer expand the file system you just mounted 3 Expand the hel loservice package This package will contain all of the files for MyHelloService If this is the first time you ve gone through these instructions then helloservice will contain a single file the source code for Si
55. Language Transformations standard giving you control over the presentation of the data and enabling you to convert the data to other XML documents or to other formats such as HTML JAXP also pro vides namespace support allowing you to work with schemas that might other wise have naming conflicts Designed to be flexible JAXP allows you to use any XML compliant parser from within your application It does this with what is called a pluggability layer which allows you to plug in an implementation of the SAX or DOM APIs The pluggability layer also allows you to plug in an XSL processor which lets you transform your XML data in a variety of ways including the way it is displayed The SAX API The Simple API for XML SAX defines an API for an event based parser Being event based means that the parser reads an XML document from begin ning to end and each time it recognizes a syntax construction it notifies the application that is running it The SAX parser notifies the application by calling methods from the ContentHandler interface For example when the parser comes to a less than symbol lt it calls the startElement method when it comes to character data it calls the characters method when it comes to the less than symbol followed by a slash lt it calls the endElement method and so on To illustrate let s look at part of the example XML document from the THE SAX API first section and walk through w
56. Map return value a get value b e If value a is a List or array coerce value b to int and return value a get value b or Array get value a value b as appropriate e If value a is a JavaBeans object coerce value b to String If value b is areadable property of value a the return result of getter call 155 156 JAVASERVER PAGES STANDARD TAG LIBRARY The EL evaluates an identifier by looking up its value as an attribute according to the behavior of PageContext findAttribute String For example product will look for the attribute named product searching the page request session and application scopes and will return its value If the attribute is not found null is returned Note that an identifier that matches one of the implicit objects described in the next section will return that implicit object instead of an attribute value Implicit Objects The JSTL expression language defines a set of implicit objects pageContext the PageContext object pageScope a Map that maps page scoped attribute names to their values requestScope a Map that maps request scoped attribute names to their values sessionScope a Map that maps session scoped attribute names to their values applicationScope a Map that maps application scoped attribute names to their values param a Map that maps parameter names to a single String parameter value obtained by calling ServletRequest getParameter String paramValues a Map that
57. Method Once a client has discovered a Web service it can invoke one of the service s methods The following example makes the remote method call getPriceList which takes no arguments As noted previously the JAX RPC runtime can deter mine the endpoint for the CoffeeOrder service which is its URI from its WSDL description If a WSDL document had not been used you would need to supply the service s URI as a command line argument After you have compiled the file CoffeeClient java here is all you need to type at the command line to invoke its getPriceList method java coffees CoffeeClient 255 256 INTRODUCTION TO WEB SERVICES The remote procedure call made by the previous line of code is a static method call In other words the RPC was determined at compile time It should be noted that with JAX RPC it is also possible to call a remote method dynamically at run time This can be done using either the Dynamic Invocation Interface DID or a dynamic proxy JAXM The Web Services Messaging with JAXM page 289 JAXM provides a stan dard way to send XML documents over the Internet from the Java platform It is based on the SOAP 1 1 and SOAP with Attachments specifications which define a basic framework for exchanging XML messages JAXM can be extended to work with higher level messaging protocols such as the one defined in the ebXML electronic business XML Message Service Specification by adding the protocol s functional
58. N Expand the WEB INF node Select the web xm1 file Select the Deployment property sheet Browse the listener property a Click the Listeners property and open the property editor b Notice that the listener class is 1isteners ContextListener Browse the servlet definition and servlet mappings a Click the Servlets property and open the property editor b Notice that the Dispatcher servlet is implemented by the Dispatcher class and that the URLs enter catalog bookdetails showcart cashier and receipt are mapped to the Dispatcher servlet Browse the tag libraries mapping a Click the Tag Libraries property and open the property editor b Notice that the relative URI struts is mapped to WEB INF lib struts jar c Notice that the relative URI template is mapped to WEB INF 1lib template jar Browse the resource references a Select the Resources Property sheet a Click the Resource References property and open the property editor b Note the resource reference named jdbc BookDB 118 CUSTOM TAGS IN JSP PAGES Using lags This section describes how a JSP page uses tags and introduces the different types of tags To use a tag a page author must do two things e Declare the tag library containing the tag e Make the tag library implementation available to the Web application Declaring Tag Libranes You declare that a JSP page will use tags defined in a tag library by includin
59. NOTATION elements for JPEG and GIF data Those can of course be obtained from some central repository But then you need to define a different ENTITY element for each image you intend to reference In other words adding a new image to your document always requires both a new entity definition in the DTD and a reference to it in the document Given the anticipated ubiquity of the HTML 4 0 specification the newer standard is to use DEFINING PARAMETER ENTITIES AND CONDITIONAL SECTIONS the MIME data types and a declaration like image which assumes the applica tion knows how to process such elements Defining Parameter Entities and Conditional Sections Just as a general entity lets you reuse XML data in multiple places a parameter entity lets you reuse parts of a DTD in multiple places In this section of the tuto rial you ll see how to define and use parameter entities You ll also see how to use parameter entities with conditional sections in a DTD Creating and Referencing a Parameter Entity Recall that the existing version of the slide presentation could not be validated because the document used lt em gt tags and those are not part of the DTD In gen eral we d like to use a whole variety of HTML style tags in the text of a slide not just one or two so it makes more sense to use an existing DTD for XHTML than it does to define all the tags we might ever need A parameter entity is intended for exactly that kind of purpose
60. address SOAPElement address order addChi l1dElement chi1ldName childName envelope createName street SOAPElement street address addChi 1dElement chi ldName street addTextNode orderBean getAddress getStreet Q childName envelope createName city SOAPElement city address addChi ldElement chi 1ldName city addTextNode orderBean getAddress getCityQ childName envelope createName state SOAPElement state address addChi 1ldElement childName state addTextNode orderBean getAddress getStateQ childName envelope createName zip SOAPElement zip address addChi 1ldElement chi ldName Zip addTextNode orderBean getAddress getZipQ The element line item has three child elements coffeeName pounds and price This information is extracted from the LineItems list contained in OrderBean for Iterator it orderBean getLineItems iterator it hasNextQO LineItemBean lib LineItemBean it nextQ childName envelope createName line item SOAPElement lineItem order addChi 1dElement chi ldName JAXM CLIENT childName envelope createName coffeeName SOAPElement coffeeName JineItem addChi 1dElement chi ldName coffeeName addTextNode lib getCoffeeName childName envelope createName pounds SOAPElement pounds JineItem addChi 1dElement chi ldName pounds addTextNode lib getPounds toStringQ childName envelope createName price
61. all cast to a SOAPElement object Here is the code that prints out the business name and description and then ends the program Iterator iterl replyBody getChildElementsQ while Citerl hasNextQ SOAPBodyElement bodyElement CSOAPBodyElement iterl next Iterator iter2 bodyElement getChildElementsQ while Citer2 hasNextQ SOAPE lement child2 CSOAPElement iter2 nextQ Iterator iter3 child2 getChildElementsQ String content child2 getValueQ System out printIn Ccontent while Citer3 hasNextQ SOAPElement child3 CSOAPElement iter3 nextQ Iterator iter4 child3 getChildElements content child3 getValueQ System out printIn content while Citer4 hasNextQ SOAPElement child4 CSOAPElement iter4 nextQ content child4 getValueQ System out printInCcontent THE UDDIPING EXAMPLE 333 connection close catch Exception ex ex printStackTrace Editing the uddi properties File In order to run this example you need to edit the uddi properties file to spec ify a UDDI registry and the appropriate proxy host and port Perform the follow ing steps 1 Mount the following filesystem by choosing Mount Filesystem from the File menu lt INSTALL gt j2eetutorial examples jaxm uddiping INSTALL is the directory where you installed the Tutorial 2 Right click the uddi properties file and choose the Edit menu item The unedited file looks like this the URLs are all on one
62. and Inte gration UDDI and ebXML make it possible for businesses to publish informa tion on the Internet about their products and Web services where the information can be readily and globally accessed by clients who want to do business Distibuted Multtiered Applications The J2EE platform uses a multitiered distributed application model for both enterprise applications Application logic is divided into components according to function and the various application components that make up a J2EE appli cation are installed on different machines depending on the tier in the multitiered J2EE environment to which the application component belongs Figure 1 1 shows two multitiered J2EE applications divided into the tiers described in the following list The J2EE application parts shown in Figure 1 1 are presented in J2EE Components page 6 e Client tier components run on the client machine e Web tier components run on the J2EE server e Business tier components run on the J2EE server e Enterprise information system EIS tier software runs on the EIS server Although a J2EE application can consist of the three or four tiers shown in Figure 1 1 J2EE multitiered applications are generally considered to be three tiered applications because they are distributed over three different locations cli ent machines the J2EE server machine and the database or legacy machines at the back end Three tiered applications that run in this way extend
63. and JAXM service on localhost If you are running either service on a different host you need to update the service URLs Importing the J AX RPC Client The Coffee Break server imports the JAX RPC client classes in the package clientutil To make the classes available for compilation and deployment 1 Make sure the filesystem lt INSTALL gt j2eetutorial examples cb jaxrpc is mounted This is required so that the IDE includes the clientutil subdirectory of jaxrpc in the classpath during compilation 2 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples cb cbservice 3 Expand the cbservice node 422 THE COFFEE BREAK APPLICATION 4 Add the clientutil subdirectory of jaxrpc to the Web module as an extra file When the IDE packages the cbservice Web module it will include the clientutil directory To add the directory as an extra file a b Cc d f g h Right click the WEB INF directory Select the Archive property sheet Click the Extra Files property and open the property editor In the Chosen Content pane select the WEB INF classes Directory Prefix from the drop down list In the Source pane expand the lt INSTALL gt j2eetutorial examples cb jaxrpc node Select the clientuti1 node Click Add Click OK 5 Right click the WEB INF node and choose View WAR Content to check that the clientutil package was added Deploying the Coffee Break Server To deploy the Coffee
64. and discovery of Web services It is a neutral third party that facilitates dynamic and loosely coupled business to business B2B interactions 446 registry provider An implementation of a business registry that conforms to a specification for XML registries request response messaging A method of messaging that includes blocking until a response is received resource manager Provides access to a set of shared resources A resource manager participates in transactions that are externally controlled and coordinated by a transac tion manager A resource manager is typically in different address space or on a different machine from the clients that access it Note An enterprise information system is referred to as resource manager when it is mentioned in the context of resource and transaction management resource manager connection An object that represents a session with a resource manager resource manager connection factory An object used for creating a resource manager connection role security An abstract logical grouping of users that is defined by the Application Assembler When an application is deployed the roles are mapped to secu rity identities such as principals or groups in the operational environment A role can be compared to a key that can open a lock Many people might have a copy of the key and the lock doesn t care who you are only that you have the right key role mapping The process of associating
65. as a JSP page Table 4 1 Duke s Bookstore Example JSP Pages Function JSP Pages Enter the bookstore bookstore jsp Create the bookstore banner banner jsp Browse the books offered for sale catalog jsp Put a book in a shopping cart catalog jsp and bookdetails jsp Get detailed information on a specific book bookdetails jsp Display the shopping cart showcart jsp Remove one or more books from the shopping cart showcart jsp Buy the books in the shopping cart cashier jsp Receive an acknowledgement for the purchase receipt jsp The data for the bookstore application is still maintained in a database However two changes are made to the database helper object database BookDB e The database helper object is rewritten to conform to JavaBeans compo nent design patterns as described in JavaBeans Component Design Conventions page 103 This change is made so that JSP pages can access the helper object using JSP language elements specific to JavaBeans com ponents THE EXAMPLE JSP PAGES 87 e Instead of accessing the bookstore database directly the helper object goes through a data access object database BookDAO The implementation of the database helper object follows The bean has two instance variables the current book and a reference to the database enterprise bean public class BookDB private String bookId 0 private BookDBEJB database null public BookDB throws Exception public void setBookId
66. as follows 1 Right click the tag Choose Customize 2 3 Select the Code Generation tab 4 Choose whether to implement an interface or extend a class which inter face or class 5 Click OK 6 Right click the tag and choose Generate Tag Handlers Once you have the skeleton you must implement the tag handler methods as described in the following sections Simple Tags Tag Handlers The handler for a simple tag must implement the doStartTag and doEndTag methods of the Tag interface The doStartTag method is invoked when the start tag is encountered This method returns SKIP_BODY because a simple tag has no body The doEndTag method is invoked when the end tag is encountered The doEndTag method needs to return EVAL_PAGE if the rest of the page needs to be evaluated otherwise it should return SKIP_PAGE The simple tag discussed in the first section lt tt simple gt would be implemented by the following tag handler TAGS WITH ATTRIBUTES 127 public SimpleTag extends TagSupport public int doStartTagQ throws JspException try pageContext getOutQ printC Hello catch Exception ex throw new JspTagException SimpleTag ex getMessage return SKIP_BODY public int doEndTag return EVAL_PAGE Tag Properties To indicate that a tag has an empty body 1 Right click the tag 2 Choose Customize 3 Choose empty from the Body Content drop down list 4 Regenerate the tag ha
67. as would be the case if you were implementing an iteration tag doAfter Body should return EVAL_BODY_BUFFERED otherwise doAfterBody should return SKIP_BODY release Method A tag handler should reset its state and release any private resources in the release method The following example reads the content of the body which contains a SQL query and passes it to an object that executes the query Since the body does not need to be reevaluated doAfterBody returns SKIP_BODY public class QueryTag extends BodyTagSupport public int doAfterBody throws JspTagException BodyContent bc getBodyContentQ get the bc as string String query bc getStringQ clean up bc clearBody try Statement stmt connection createStatement result stmt executeQuery query catch SQLException e throw new JspTagExceptionC QueryTag e getMessage return SKIP_BODY Tag Properties Body content containing custom and core tags scripting elements and HTML text is categorized as JSP This is the value declared for the Struts logic present tag All other types of body content for example SQL state ments passed to the query tag would be labeled tagdependent To indicate that a tag has a body 1 Right click the tag 2 Choose Customize 132 CUSTOM TAGS IN JSP PAGES 3 Choose the content type from the Body Content drop down list 4 Regenerate the tag handler Tags That Define Scnpting Va
68. be a supported JAX RPC type For an example see the sec tion JavaBeans Components page 411 Creating a Web Service with J AX RPC This section describes how to build and deploy a simple Web service named MyHel loService using Sun ONE Studio 4 and Sun ONE Application Server 7 For the sake of brevity instructions in this section refer to Sun ONE Studio 4 as the IDE After you ve deployed MyHel11loService you can access it by the cli ents discussed in Creating Web Service Clients with JAX RPC page 276 Note The instructions that follow were written for Sun ONE Studio 4 update 1 Enterprise Edition If you are running a later version then you should refer to the VERIFYING THE IDE SETTINGS 273 Sun ONE Studio Programming Series for up to date instructions See Further Information page 286 These are the basic steps for creating a Web service 1 Code and compile a class that implements the service s methods 2 Create the service New Web Services Web Service 3 Generate the service s helper classes and WSDL file Right click the ser vice node and choose Generate Web Service 4 Deploy the service Right click the service node and choose Deploy The sections that follow cover these steps in greater detail Verifying the IDE Settings Before building MyHe11loService check the following e The Sun ONE Application Server 7 has been installed a In the Runtime pane of the Explorer choose Server Registry
69. be displayed by tools Small Icon Optional small icon that can be used by tools Large Icon Optional large icon that can be used by tools Description Optional tag specific information To add a tag to a tag library using the IDE 1 Right click the TLD file and choose Add Tag 2 Type the tag name and tag class name 3 Click OK The following sections describe the tag handler methods you need to develop and the properties you need to specify for each type of tag introduced in Types of Tags page 119 TAG HANDLERS Tag Handlers A tag handler is an object invoked by a Web container to evaluate a custom tag during the execution of the JSP page that references the tag Tag handlers must implement either the Tag or BodyTag interface Interfaces can be used to take an existing Java object and make it a tag handler For newly created handlers you can use the TagSupport and BodyTagSupport classes as base classes These classes and interfaces are contained in the javax servlet jsp tagext pack age Tag handler methods defined by the Tag and BodyTag interfaces are called by the JSP page s servlet at various points during the evaluation of the tag When the start tag of a custom tag is encountered the JSP page s servlet calls methods to initialize the appropriate handler and then invokes the handler s doStartTag method When the end tag of a custom tag is encountered the handler s doEnd Tag method is invoked Additional
70. bodyIt2 next String shippingDate sDate getValue Date date df parse shippingDate Calendar cal new GregorianCalendar cal setTime date cb new ConfirmationBean cb setOrderId id cb setShippingDate cal J SP Pages orderFom orderForm displays the current contents of the shopping cart The first time the page is requested the quantities of all the coffees are 0 Each time the customer changes the coffees amounts and clicks the Update button the request is posted back to orderForm The Dispatcher servlet updates the values in the shopping cart which are then redisplayed by orderForm When the order is complete the customer proceeds to the checkoutForm page by clicking the Checkout link checkoutFom checkoutForm is used to collect delivery and billing information for the cus tomer When the Submit button is clicked the request is posted to the check outAck page However the request is first handled by the Dispatcher which invokes the validate method of checkoutFormBean If the validation does not succeed the requested page is reset to checkoutForm with error notifications in each invalid field If the validation succeeds checkoutFormBean submits subor ders to each distributor and stores the result in the request scoped OrderConfir mations JavaBeans component and control is passed to checkoutAck JAVABEANS COMPONENTS 411 checkoutAck checkoutAck simply displays the contents of the OrderConfirmat
71. books rowsByIndex gt lt jsp useBean id bid type java lang String gt lt jsp useBean id bookRow type java lang Object gt lt jsp useBean id addedBook class database BookDetails scope page gt lt jsp setProperty name addedBook property bookId value lt bookRow 0 gt _ gt lt jsp setProperty name addedBook property Surname value lt bookRow 1 gt _ gt lt jsp setProperty name addedBook property firstName value lt bookRow 2 gt _ gt lt jsp setProperty name addedBook property title value lt bookRow 3 gt _ gt lt jsp setProperty name addedBook property price value lt Double bookRow 4 floatValueQ gt gt lt jsp setProperty name addedBook property year value lt Integer bookRow 5 gt gt lt jsp setProperty name addedBook property description value lt bookRow 6 gt gt lt jsp setProperty name addedBook property inventory value lt Integer bookRow 7 gt gt lt jsp useBean gt lt cart add bid addedBook gt lt c forEach gt Further Information For further information on JSTL see e The JSTL samples shipped with Sun ONE Application Server 7 The sam ples are in the directory lt S1AS7_HOME gt samples webapps jst1 e Resources listed on the Web site http java sun com prod ucts jsp jstl e Reference documentation at http jakarta apache org taglibs doc standard doc stan dard index
72. br gt amp nbsp lt br gt lt h4 gt lt fmt message key Critics gt lt h4 gt lt blockquote gt lt c out value book description gt lt blockquote gt lt h4 gt lt fmt message key ItemPrice gt lt fmt formatNumber value book price type currency gt lt h4 gt lt c forEach gt The following excerpt from catalog jsp uses the Row interface to retrieve val ues from the columns of a book row using scripting language expressions First the book row that matches a request parameter bid is retrieved from the data base Since the bid and bookRow objects are later used by tags that use scripting language expressions to set attribute values and a scriptlet that adds a book to the shopping cart both objects are declared as scripting variables using the jsp useBean tag The page creates a bean that describes the book and scripting language expressions are used to set the book properties from book row column values Finally the book is added to the shopping cart You might want to compare this version of catalog jsp to the versions in Jav aServer Pages Technology page 83 and Custom Tags in JSP Pages page 113 that use a book database JavaBeans component lt sql query var books dataSource applicationScope bookDS gt select from PUBLIC books where id lt sql param value bid gt 175 176 JAVASERVER PAGES STANDARD TAG LIBRARY lt sql query gt lt c forEach var bookRow begin 0 items
73. class e Whether the variable refers to a new object e The availability of the variable COOPERATING TAGS The Web container passes a parameter called data to the getVariableInfo method that contains attribute value tuples for each of the tag s attributes These attributes can be used to provide the VariableInfo object with a scripting vari able s name and class The iterator tag library provides information about the scripting variable created by the iterator tag in the IteratorTEI tag extra info class because the script ing variable customizer does not allow a tag attribute to specify the type of the variable Since the name member and class org Member of the scripting vari able are passed in as tag attributes they are be retrieved with the data getAt tributeString method and used to fill in the VariableInfo constructor To allow the scripting variable name to be used within the scope of the tag the scope of book is set to be NESTED public class IteratorTEI extends TagExtraInfo public VariableInfo getVariableInfo TagData data VariableInfo infol new VariableInfo data getAttributeStringC name data getAttributeString type true VariableInfo NESTED VariableInfo info infol return info Since the tag library customizer does not have a TEI class property the fully qualified name of the tag extra info class defined for a scripting variable must be manually added to the TLD in the tei
74. code e Whenever you find yourself writing the same thing more than once think entity That lets you write it one place and reference it multiple places e Ifthe information is likely to change especially if it is used in more than one place definitely think in terms of defining an entity An example is defining productName as an entity so that you can easily change the docu ments when the product name changes e If the entity will never be referenced anywhere except in the current file define it in the local_subset of the document s DTD much as you would define a method or inner class in a program e If the entity will be referenced from multiple documents define it as an external entity the same way that would define any generally usable class as an external class External entities produce modular XML that is smaller easier to update and maintain They can also make the resulting document somewhat more difficult to visualize much as a good OO design can be easy to change once you under stand it but harder to wrap your head around at first NORMALIZING DTDS You can also go overboard with entities At an extreme you could make an entity reference for the word the it wouldn t buy you much but you could do it Note The larger an entity is the less likely it is that changing it will have unin tended effects When you define an external entity that covers a whole section on installation instructions for examp
75. connection gt lt x query id balances gt SELECT account balance FROM acct_table where customer_number lt request getCustno gt lt x query gt lt tt connection gt The TLD for the tag handler must indicate that the connection attribute is optional with the following declaration lt tag gt lt attribute gt lt name gt connection lt name gt lt required gt false lt required gt lt attribute gt lt tag gt Examples The custom tags described in this section demonstrate solutions to two recurring problems in developing JSP applications minimizing the amount of Java pro gramming in JSP pages and ensuring a common look and feel across applica tions In doing so they illustrate many of the styles of tags discussed in the first part of the chapter An Iteration Tag Constructing page content that is dependent on dynamically generated data often requires the use of flow control scripting statements By moving the flow control logic to tag handlers flow control tags reduce the amount of scripting needed in JSP pages 138 CUSTOM TAGS IN JSP PAGES An iterator tag retrieves objects from a collection stored in a JavaBeans compo nent and assigns them to a scripting variable The body of the tag retrieves infor mation from the scripting variable While elements remain in the collection the iterator tag causes the body to be reevaluated To run the example described in this section 1 In the IDE moun
76. d nextQ System out printIn distributor ArrayList lis new ArrayListQ BigDecimal price new BigDecimal 0 00 BigDecimal total new BigDecimal 0 00 for Iterator c cart getItemsQ iteratorQ c hasNextQ ShoppingCartItem sci ShoppingCartItem c nextQ if C sci getItemQ getDistributor d equals distributor amp amp sci getPounds floatValue Q gt 0 price sci getItem getWholesalePricePerPound multiply sci getPounds total total add price JAVABEANS COMPONENTS 413 LineItemBean li new LineItemBean 1i setCoffeeName sci getItem Q getCoffeeNameQ 1i1 setPounds sci getPounds li setPrice sci getItem Q getWholesalePricePerPound lis add 1i if C lis isEmptyQ OrderBean cbhorder new OrderBean cborder setId orderlId cborder setCustomer cbcustomer cborder setLineItems 1lis cborder setTotal total cborder setAddress cbaddress String cbpropsName cbservice CoffeeServices ResourceBundle cbpropBundle ResourceBundle getBundle cbpropsName String JAXMOrderURL cbpropBundle getStringC JAXMOrder url if Cdistributor equalsCJAXMOrderURL JAXMOrderRequest or new JAXMOrderRequest JAXMOrderURL cbconfirmation or placeOrder cborder else clientutil OrderGenClient CustomerBean customer new clientutil OrderGenClient CustomerBean customer setFirstName firstName customer setLastName lastName customer setPhoneNumber
77. default value For example to view the properties of the direct attribute of the tem plate parameter tag 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web temp late Expand the template TLD node Expand the parameter tag node Expand the Attributes node RW N 5 Right click the direct attribute and choose Customize Notice how attribute is required that its value can be set by a runtime expression and that its type is boolean If you change a tag attribute you must regenerate the tag handler TAGS WITH ATTRIBUTES Attribute Validation The documentation for a tag library should describe valid values for tag attributes When a JSP page is translated a Web container will enforce any con straints contained in the TLD element for each attribute The attributes passed to a tag can also be validated at translation time with the isValid method of a class derived from TagExtraInfo This class is also used to provide information about scripting variables defined by the tag see Provid ing Information about the Scripting Variable page 133 The isValid method is passed the attribute information in a TagData object which contains attribute value tuples for each of the tag s attributes Since the validation occurs at translation time the value of an attribute that is computed at request time will be set to TagData REQUEST_TIME_VALUE Assume that the attribute attr1 of a tag is of type bool
78. for information in accordance with the javax xml registry infomodel interfaces An optional interface DeclarativeQueryManager allows the client to use SQL syntax for queries The implementation of JAXR in the Sun ONE Application Server does not implement DeclarativeQuery Manager e BusinessLifeCycleManager which allows the client to modify the infor mation in a registry by either saving it updating it or deleting it When an error occurs JAXR API methods throw a JAXRException or one of its subclasses Many methods in the JAXR API use a Collection object as an argument or a returned value Using a Collection object allows operations on several registry objects at a time Figure 11 1 illustrates the architecture of JAXR In the Sun ONE Application Server a JAXR client uses the capability level 0 interfaces of the JAXR API to access the JAXR provider The JAXR provider in turn accesses a registry The Sun ONE Application Server supplies a JAXR provider for UDDI registries JAXA API Capabilily Specific interfaces j H a y ebNiAL Provider LUGO Prori der Daher Previder Specific JAXA Provider Diverse Aegistries chWx ML Figure 11 1 JAXR Architecture IMPLEMENTING A JAXR CLIENT 351 Implementng a J AXR Client This section describes the basic steps to follow in order to implement a JAXR client that can perform queries and updates to a UDDI registry A JAXR client is a client program that can access registries using the JAX
79. for the JAXM API the javax xm1 soap and javax xml messaging packages at lt S1STUDIO_HOME gt jwsdp docs api index htm Note lt S1STUDIO_HOME gt is the directory where Sun ONE Studio is installed Continuously Active A messaging provider works continuously A JAXM client may make a connec tion with its provider send one or more messages and then close the connection The provider will store the message and then send it Depending on how the pro vider has been configured it will resend a message that was not successfully delivered until it is successfully delivered or until the limit for the number of resends is reached Also the provider will stay in a waiting state ready to receive any messages that are intended for the client The provider will store incoming messages so that when the client connects with the provider again the provider will be able to forward the messages In addition the provider generates error messages as needed and maintains a log where messages and their related error messages are stored 299 300 WEB SERVICES MESSAGING WITH JAXM Intermediate Destinations When a messaging provider is used a message can be sent to one or more inter mediate destinations before going to the final recipient These intermediate desti nations called actors are specified in the message s SOAPHeader object For example assume that a message is an incoming Purchase Order The header might route the message to
80. getAttributeStringC type true VariableInfo NESTED VariableInfo info infol return info A template Tag Library A template provides a way to separate the common elements that are part of each screen from the elements that change with each screen of an application Putting all the common elements together into one file makes it easier to maintain and enforce a consistent look and feel in all the screens It also makes development of individual screens easier because the designer can focus on portions of a screen that are specific to that screen while the template takes care of the com mon portions The template is a JSP page with placeholders for the parts that need to change with each screen Each of these placeholders is referred to as a parameter of the template For example a simple template could include a title parameter for the top of the generated screen and a body parameter to refer to a JSP page for the custom content of the screen 142 CUSTOM TAGS IN JSP PAGES The template uses a set of nested tags definition screen and parameter to define a table of screen definitions and uses an insert tag to insert parameters from a screen definition into a specific application screen J SP Page The template for the Duke s Bookstore example template jsp is shown below This page includes a JSP page that creates the screen definition and then uses the insert tag to insert parameters from the definition into
81. http sonata coffeebreak com SOAPBodyElement requestPrices body addBodyE lement bodyName In the next few lines the code adds the element request to the element request prices represented by the SOAPBodyElement requestPrices Then the code adds a text node containing the text of the request Next because there are no other elements in the request the code calls the method saveChanges on the message to save what has been done Name requestName envelope createName request SOAPElement request requestPrices addChi 1dElement requestName request addTextNode Send updated price list msg saveChanges With the creation of the request message completed the code sends the message to the JAXM coffee supplier The message being sent is the SOAPMessage object msg to which the elements created in the previous code snippets were added The endpoint is the URI for the JAXM coffee supplier The SOAPConnection object con is used to send the message and because it is no longer needed it is closed URL endpoint new URL url SOAPMessage response con call msg endpoint con close JAXM CLIENT When the call method is executed the application server executes the servlet PriceListServlet This servlet creates and returns a SOAPMessage object whose content is the JAXM distributor s price list PriceListServlet is dis cussed in Returning the Price List page 395 The application server knows to execute Pri
82. in a future release of the tutorial For a complete list ing and description of the features see the Java Servlet specification In the following sections some examples demonstrate procedures for configur ing the Hello World application If Hello World does not use a specific configu ration feature the section gives uses other examples for illustrating the deployment descriptor element and describes generic procedures for specifying the feature using the IDE Extended examples that demonstrate how to use the IDE are in The Example Servlets page 48 and The Example JSP Pages page 150 Request Mapping When a request is received by the Sun application server it must determine which Web component should handle the request It does so by mapping the URL path contained in the request to a Web application and a Web component A URL path contains the context path and a servlet path http lt host gt 80 context_path servlet_path A context path identifies a Web application For example to view the context of the Hello1 application 1 Select the WEB INF node of the Hellol Web module 2 Note that the Context Root property value is set to he1101 The servlet path identifies the Web component that should handle a request The servlet path must start with a and end with a string or a wildcard expression with an extension jsp for example Since Web containers automatically map a servlet path that ends with jsp you do not have
83. information about a problem However a SOAPFault object is quite different in that it is an element in a message s SOAPBody object rather than part of the try catch mechanism used for Exception objects Also as part of the SOAPBody object which pro vides a simple means for sending mandatory information intended for the ulti mate recipient a SOAPFault object only reports status or error information It does not halt the execution of an application the way an Exception object can Various parties may supply a SOAPFau1t object in a message If you are a standa lone client using the SAAJ API and thus sending point to point messages the recipient of your message may add a SOAPFault object to the response to alert you to a problem For example if you sent an order with an incomplete address for where to send the order the service receiving the order might put a SOAP Fault object in the return message telling you that part of the address was miss ing In another scenario if you use the JAXM 1 1_01 API or later in order to use a messaging provider the messaging provider may be the one to supply a SOAP Fault object For example if the provider has not been able to deliver a message because a server is unavailable the provider might send you a message with a 319 320 WEB SERVICES MESSAGING WITH JAXM SOAPFault object containing that information In this case there was nothing wrong with the message itself so you can try sending i
84. interfaces for traversing the tree and writing an XML version of it DTD Document Type Definition An optional part of the document prolog as specified by the XML standard The DTD specifies constraints on the valid tags and tag sequences that can be in the document The DTD has a number of shortcomings however which has led to various schema proposals For example the DTD entry lt ELEMENT username PCDATA gt says that the XML element called username contains Parsed Character DATA that is text alone with no other structural elements under it The DTD includes both the local subset defined in the current file and the external subset which consists of the definitions contained in external dtd files that are ref erenced in the local subset using a parameter entity ABCDEFGHIJKLMNOPQRSTUVWXYZ ebXML Electronic Business XML A group of specifications designed to enable enterprises to conduct business through the exchange of XML based mes sages It is sponsored by OASIS and the United Nations Centre for the Facil itation of Procedures and Practices in Administration Commerce and Transport U N CEFACT element A unit of XML data delimited by tags An XML element can enclose other elements empty tag A tag that does not enclose any content 435 enterprise bean A component that implements a business task or business entity and resides in an EJB container either an entity bean session bean or message driven bean
85. it to process Add the text highlighted below to add a processing instruction for a mythical slide presentation program that will query the user to find out which slides to display technical executive level or all lt slideshow Notes gt lt PROCESSING INSTRUCTION gt lt my presentation Program QUERY exec tech all gt lt TITLE SLIDE gt The data portion of the processing instruction can contain spaces or may even be null But there cannot be any space between the initial lt and the target identifier The data begins after the first space Fully qualifying the target with the complete Web unique package prefix makes sense so as to preclude any conflict with other programs that might process the same data For readability it seems like a good idea to include a colon after the name of the application like this lt my presentation Program QUERY gt The colon makes the target name into a kind of label that identifies the intended recipient of the instruction However while the w3c spec allows in 66 99 a target name some versions of IES consider it an error For this tutorial then we avoid using a colon in the target name Save a copy of this file as slideSamp1le 2 xm1 so you can use it when experi menting with processing instructions 205 206 UNDERSTANDING XML Intoducing an Enor The parser can generate one of three kinds of errors fat
86. java util Iterator it sb getChildElements bodyName SOAPBodyElement bodyElement CSOAPBodyElement it nextQ String lastPrice bodyElement getValue System out printC The last price for SUNW is System out printIn ClastPrice If there were more than one element with the name bodyName you would have had to use a while loop using the method Iterator hasNext to make sure that you got all of them while Cit hasNextQ SOAPBodyElement bodyElement CSOAPBodyElement it nextQ String lastPrice bodyElement getValueQ System out print The last price for SUNW is System out printIn lastPrice At this point you have seen how to send a request response message as a standa lone client You have also seen how to get the content from the response The next part shows you how to send a message using a messaging provider Client with a Messaging Provider Using a messaging provider gives you more flexibility than a standalone client has because it can take advantage of the additional functionality that a messaging provider can offer 310 WEB SERVICES MESSAGING WITH JAXM Getting a ProviderC onnection Object Whereas a SOAPConnection object is a point to point connection directly to a particular URL a ProviderConnection object is a connection to a messaging provider With this kind of connection all messages that you send or receive go through the messaging provider As with getting a SOAPConnection object the firs
87. long as it2 has another element the method next will return the next coffee element Iterator it2 bodyE1 getChildElementsQ while it2 hasNextQ SOAPElement child2 SOAPElement it2 nextQ 405 406 THE COFFEE BREAK APPLICATION The next lines of code drill down another level to retrieve the coffee name and price elements contained in it3 Then the message getValue retrieves the text a coffee name or a price that the JAXM coffee distributor added to the coffee name and price elements when it gave content to response The final line in the following code fragment adds the coffee name or price to the Vector object list Note that because of the nested while loops for each coffee element that the code retrieves both of its child elements the coffee name and price ele ments are retrieved Iterator it3 child2 getChildElementsQ while it3 hasNextQ SOAPElement child3 CSOAPElement it3 nextQ String value child3 getValueQ list addElement value The last code fragment adds the coffee names and their prices as a PriceLis tItem to the ArrayList priceItems and prints each pair on a separate line Finally it constructs and returns a PriceListBean ArrayList priceItems new ArrayList for Cint i 0 i lt list sizeQ i i 2 new PriceItemBean pib setCoffeeName list elementAt i toStringQ pib setPricePerPound new BigDecimal list elementAt i 1 toStringQ pricelItems add pib Date
88. messaging provider and run in a container The samples JAXM Simple SAAJ Simple JAXM Translator and JAXM Tags are examples of this type e Those that use a messaging provider and run in a container There are no samples of this type at this release Setting the Classpath Before you can compile and run the examples you need to set the classpath for both compiling and executing the programs To set the compilation and execution classpaths 1 Choose Options from the Tools menu 2 Expand the Building node then the Compiler Types node 3 Choose External Compilation 4 Select the Expert tab 5 Click the Class Path property and open the property editor CHANGING SERVER PERMISSIONS 6 Click Add JAR Zip 7 In the file chooser navigate to the directory lt S1STUDIO_HOME gt jwsdp common lib and choose the file jaxm api jar 8 Click OK 9 Click Add JAR Zip again and repeat steps 7 8 This time choose the file commons logging jar 10 Expand the Debugging and Executing node then the Execution Types node 11 Choose External Execution 12 Select the Expert tab 13 Click the Class Path property then double click the ellipsis in the value field 14 In the property editor click Add JAR Zip 15 In the file chooser navigate to the directory lt S1STUDIO_HOME gt jwsdp common 1lib and choose the jaxm api jar file 16 Click OK 17 Click Close in the Options window Changing Server Permissions Two of the e
89. methods are invoked in between when a tag handler needs to interact with the body of the tag For further information see Tags with Bodies page 130 In order to provide a tag handler implementation you must implement the methods summarized in Table 5 3 that are invoked at various stages of processing the tag Table 5 3 Tag Handler Methods Simple doStartTag doEndTag release doStartTag doEndTag set getAttributel N Attributes release Body Evaluation and No doStartTag doEndTag release Interaction Body Iterative Evaluation doStartTag doAfterBody doEndTag release doStartTag doEndTag release doInitBody doAfterBody release Body Interaction A tag handler has access to an API that allows it to communicate with the JSP page The entry point to the API is the page context object javax serv let jsp PageContext through which a tag handler can retrieve all the other implicit objects request session and application accessible from a JSP page 125 126 CUSTOM TAGS IN JSP PAGES Implicit objects can have named attributes associated with them Such attributes are accessed using set get Attribute methods If the tag is nested a tag handler also has access to the handler called the par ent associated with the enclosing tag A set of related tag handler classes a tag library is usually packaged and deployed as a JAR archive You can generate a tag handler skeleton with the IDE
90. multiple items For an example after defining an image element coming up shortly you could declare that every image element must be paired with a title element in a slide by specifying Cimage title Here the plus sign applies to the image title pair to indicate that one or more pairs of the specified items can occur Defning Textand Nested Hements Now that you have told the parser something about where not to expect text let s see how to tell it where text can occur Add the text highlighted below to define the slide title item and list elements lt ELEMENT slideshow slide gt lt ELEMENT slide title item gt lt ELEMENT title PCDATA gt lt ELEMENT item C PCDATA item gt The first line you added says that a slide consists of a title followed by zero or more item elements Nothing new there The next line says that a title consists entirely of parsed character data PCDATA That s known as text in most parts of the country but in XML speak it s called parsed character data That dis tinguishes it from CDATA sections which contain character data that is not CREATING A DOCUMENT TYPE DEFINITION DTD parsed The that precedes PCDATA indicates that what follows is a special word rather than an element name The last line introduces the vertical bar which indicates an or condition In this case either PCDATA or an item can occur The asterisk at the end says that either o
91. nature of DTD specifications is that it is not clear what comments are meant to explain A comment at the top like lt Address used for mailing via the postal system gt would apply to all of the elements that constitute a mailing address But a comment like lt Addressee gt would apply to the name element only On the other hand a comment like lt A 5 digit string gt would apply specifically to the PCDATA part of the zipcode element to describe the valid formats Finally DTDs do not allow you to formally specify field validation criteria such as the 5 digit or 5 and 4 limitation for the zipcode field Finally a DTD uses syntax which substantially different from XML so it can t be processed with a standard XML parser That means you can t read a DTD into a DOM for example modify it and then write it back out again SCHEMA STANDARDS To remedy these shortcomings a number of proposals have been made for a more database like hierarchical schema that specifies validation criteria The major proposals are shown below XML Schema A large complex standard that has two parts One part specifies structure rela tionships This is the largest and most complex part The other part specifies mechanisms for validating the content of XML elements by specifying a poten tially very sophisticated datatype for each element The good news is that XML Schema for Structures lets you specify any kind of relationsh
92. of the message and also the information needed for it to act as source input A StreamSource object will contain the content as an XML document the SAX Source or DOMSource object will contain content and instructions for transform ing it into an XML document The following code fragments illustrates adding content as a DOMSource object The first step is to get the SOAPPart object from the SOAPMessage object Next the code uses methods from the JAXP API to build the XML document to be added It uses a DocumentBuilderFactory object to get a DocumentBui Ider object Then it parses the given file to produce the document that will be used to initialize a new DOMSource object Finally the code passes the DOMSource object domSource to the method SOAPPart setContent SOAPPart soapPart message getSOAPPart DocumentBuilderFactory dbf DocumentBui lderFactory newInstance DocumentBuilder db dbf newDocumentBui lder Document doc db parse file foo bar soap xm1 DOMSource domSource new DOMSource doc soapPart setContent domSource Populating the Attachment Part of a Message A Message object may have no attachment parts but if it is to contain anything that is not in XML format that content must be contained in an attachment part There may be any number of attachment parts and they may contain anything from plain text to image files In the following code fragment the content is an image in a JPEG file whose URL is
93. performing the steps in this section you must first create and deploy the MyHelloService as described in Creating a Web Service with JAX RPC page 272 The steps for building and running the DynamicProxyHello client are the same as those described in Building and Running the StaticStub Hello Client page 278 with the following exceptions 1 In the New wizard s Specify Web Service Client pane enter MyDynamic in the Name field and dynamicproxy in the Package field 2 When you execute the DynamicProxyHello client the Output window should display this line Hello Buzz Dynamic Invocation Interface DII Client Example With the dynamic invocation interface DID a client can call a remote procedure even if the signature of the remote procedure or the name of the service are unknown until runtime In contrast to a static stub or dynamic proxy client a DII client does not require runtime classes generated by the IDE However as you ll see in the following section the source code for a DII client is more complicated than the code of the other two types of clients Note This example is for advanced users who are familiar with WSDL documents See Further Information page 286 DYNAMIC INVOCATION INTERFACE DII CLIENT EXAMPLE 283 DilHello Source Code The DIIHe11o0 program performs these steps 1 Creates a Service object Service service factory createService new QName qnameService To get a Service object th
94. prefix and a namespace URI As you saw earlier a SOAPBodyElement object is required to have a fully qualified namespace but child elements added to it may have Name objects with only the local name SOAPBody body envelope getBody Name bodyName envelope createName PurchaseLineItems PO http sonata fruitsgalore com SOAPBodyElement purchaseLineItems body addBodyE1ement bodyName Name childName envelope createName Order SOAPElement order purchaseLineltems addChi 1dElement chi 1dName childName envelope createName Product SOAPElement product order addChi 1dElement chi 1dName product addTextNodeC Apple childName envelope createName Price 313 314 WEB SERVICES MESSAGING WITH JAXM SOAPElement price order addChildElement chi ldName price addTextNode 1 56 childName envelope createName Order SOAPElement order2 purchaseLinelItems addChi 1dElement chi ldName childName envelope createName Product SOAPElement product2 order2 addChi1dElement chi ldName product2 addTextNode Peach childName envelope createName Price SOAPElement price2 order2 addChi1ldElement chi ldName price2 addTextNode 1 48 The JAXM code in the preceding example produces the following XML in the SOAP body lt PO PurchaseLineltems xmIns PO http www sonata fruitsgalore order gt lt Order gt lt Product gt App1e lt Product gt lt Pric
95. print them out The class CoffeeOrderServiceImp is one of the classes generated by the map ping tool It is a stub factory whose only method is getCoffeeOrderIF in other words its whole purpose is to create instances of CoffeeOrderIF The instances INVOKING A REMOTE METHOD of CoffeeOrderIF that are created by CoffeeOrderServiceImp are client side stubs that can be used to invoke methods defined in the interface CoffeeOr derIF Thus the variable coffeeOrder represents a client stub that can be used to call getPriceList one of the methods defined in CoffeeOrderTF The method getPriceList will block until it has received a response and returned it Because a WSDL document is being used the JAX RPC runtime will get the service endpoint from it Thus in this case the client class does not need to specify the destination for the remote procedure call When the service endpoint does need to be given it can be supplied as an argument on the com mand line Here is what a client class might look like package coffees public class CoffeeClient public static void main String args try CoffeeOrderIF coffeeOrder new CoffeeOrderServiceImp1 getCoffeeOrderIFQ Coffee priceList coffeeOrder getPriceListQ for Cint i 0 i lt priceList length i System out print priceList i getNameQ System out printIn priceList i getPriceQ catch Exception ex ex printStackTraceQ Invoking a Remote
96. reference environment entries resource environment entries or resources such as databases you must declare the references with in the Web application deployment descriptor To add a reference in the IDE 1 Mount the Web module as a filesystem 2 Expand the WEB INF node O ON DN FW DEPLOYING WEB MODULES Select the web xm1 file In the properties sheet select the References tab Click the Resource References Property and open the property editor Click Add Type a JNDI name for the resource Choose the type of the resource Choose whether the container or the application performs authentication when the resource is accessed 10 Choose whether the resource can be shared by more than one Web appli cation For an example resource reference see Configuring the Web Application to Ref erence a Data Source with JNDI page 44 Deploying Web Modules Before a Web application can be accessed it must be deployed as a Web module in the application server For example to deploy the hellol Web module in the IDE 1 Start the Sun ONE Application Server 7 2 Verify that the Sun ONE Application Server 7 has been installed a b In the Runtime pane of the Explorer choose the node Server Regis try Installed Servers Verify that the Sun ONE Application Server 7 is listed below Installed Servers If it is not listed 1 Install the Sun ONE Application Server Plugin as described in Sun ONE Stud
97. response If the resource is static the include method enables programmatic server side includes If the resource is a Web component the effect of the method is to send the request to the included Web component execute the Web component and then include the result of the execution in the response from the containing serv let An included Web component has access to the request object but it is limited in what it can do with the response object e It can write to the body of the response and commit a response e It cannot set headers or call any method for example setCookie that affects the headers of the response The banner for the Duke s Bookstore application is generated by BannerServ let Note that both the doGet and doPost methods are implemented because BannerServlet can be dispatched from either method in a calling servlet public class BannerServlet extends HttpServlet public void doGet HttpServletRequest request HttpServletResponse response throws ServletException IOException PrintWriter out response getWriterQ out printInC lt body bgcolor FFFFFF gt lt center gt lt hr gt lt br gt amp nbsp lt h1 gt lt font size 3 color CCQ066 gt Duke s lt font gt lt img src request getContextPath duke books gif gt lt font size 3 color black gt Bookstore lt font gt lt hi gt lt center gt lt br gt amp nbsp lt hr gt lt br g
98. scope is properly synchronized JSP SCRIPTING ELEMENTS J SP Scripting Elements JSP scripting elements are used to create and access objects define methods and manage the flow of control Since one of the goals of JSP technology is to sepa rate static template data from the code needed to dynamically generate content very sparing use of JSP scripting is recommended Much of the work that requires the use of scripts can be eliminated by using custom tags described in Custom Tags in JSP Pages page 113 JSP technology allows a container to support any scripting language that can call Java objects If you wish to use a scripting language other than the default java you must specify it in a page directive at the beginning of a JSP page lt page language scripting language gt Since scripting elements are converted to programming language statements in the JSP page s servlet class you must import any classes and packages used by a JSP page If the page language is java you import a class or package with the page directive lt page import packagename fully_qualified_classname gt For example the bookstore example page showcart jsp imports the classes needed to implement the shopping cart with the following directive lt page import java util cart gt Declarations A JSP declaration is used to declare variables and methods in a page s scripting language The syntax for a declaration is as foll
99. shopping cart Users can view and modify the shopping cart Once users are finished shopping they can purchase the books in the cart The Duke s Bookstore examples share common classes and a database schema These files are located in the directory lt INSTALL gt j2eetutorial examples web bookstore The common classes are packaged into a JAR and already included in the WEB INF 1ib directory in each version of Duke s Bookstore example To recreate the bookstore library JAR 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstore 2 Expand the bookstore node 3 Right click the bookstore node and choose Compile 4 Create the bookstore JAR a Right click the bookstore node and choose New gt JAR Packager gt JAR Recipe b Type bookstore for the Recipe Name c Click Next d Select the cart database exception and messages packages and click Add e Click Next twice f Click Generate to generate the JAR manifest g Click Finish 5 Right click the bookstore JAR recipe node and choose Compile 6 Expand the bookstore JAR recipe node 37 INTRODUCTION TO WEB APPLICATIONS Intemationalizing and Localizing Web Applications Internationalization is the process of preparing an application to support various languages and data formats Localization is the process of adapting an interna tionalized application to support a specific language or locale Although all cli ent user interface
100. short Anays JAX RPC also supports arrays with members of supported JAX RPC types Examples of supported arrays are int and String Multidimensional arrays such as BigDecimal are also supported 272 BUILDING WEB SERVICES WITH JAX RPC Application Classes JAX RPC also supports classes that you ve written for your applications In an order processing application for example you might provide classes named Order LineItem and Product The JAX RPC Specification refers to such classes as value types because their values or states may be passed between clients and remote services as method parameters or return values To be supported by JAX RPC an application class must conform to the follow ing rules e It must have a public default constructor e It must not implement either directly or indirectly the java rmi Remote interface e Its fields must be supported JAX RPC types The class may contain public private or protected fields For its value to be passed or returned during a remote call a field must meet these requirements e A public field cannot be final or transient e A non public field must have corresponding getter and setter methods JavaBeans Components JAX RPC also supports JavaBeans components which must conform to the same set of rules as application classes In addition a JavaBeans component must have a getter and setter method for each bean property The type of the bean property must
101. source and choose Register NYDN fs Select the application server that you want the data source to be registered in and click Register Click OK 9 Expand the Registered JOBC Connection Data Sources node and notice that jdbc BookDB is listed o0 Configuring the Web Application to Reference a Data Source with J NDI In order to access a database from a Web application you must declare resource reference in the application s Web application deployment descriptor see Refer ences to Environment Entries Resource Environment Entries or Resources page 32 The resource reference declares a JNDI name the type of the data resource and the kind of authentication used when the resource is accessed The JNDI name is used to create a data source object in the database helper class database BookDB public BookDB throws Exception try Context initCtx new InitialContextQ Context envCtx Context initCtx lookupC java comp env DataSource ds DataSource envCtx lookup jdbc BookDB con ds getConnection System out printInC Created connection to database catch Exception ex System out printInC Couldn t create connection ex getMessage throw new Exception Couldn t open connection to database ex getMessage MAPPING THE WEB APPLICATION JNDI NAME TO A DATA SOURCE 45 To specify a resource reference to the bookstore data source Select the Web module Expand the WEB INF node
102. space required for encoding UTF 16 UTF 16 is a 16 bit encoding scheme It is large enough to encode all the characters from all the alphabets in the world It uses 16 bits for most char acters but includes 32 bit characters for ideogram based languages like Chi nese A Western European language document that uses UTF 16 will be 425 426 JAVA ENCODING SCHEMES twice as large as the same document encoded using UTF 8 But documents written in far Eastern languages will be far smaller using UTF 16 Note UTF 16 depends on the system s byte ordering conventions Although in most systems high order bytes follow low order bytes in a 16 bit or 32 bit word some systems use the reverse order UTF 16 documents cannot be interchanged between such systems without a conversion Further Information For a complete list of the encodings that can be supported by the Java 2 platform see http java sun com j2se 1 3 docs guide int1l encoding doc htm B HTIP Overview Stephanie Bodoff Mosr Web clients use the HTTP protocol to communicate with a J2EE server HTTP defines the requests that a client can send to a server and responses that the server can send in reply Each request contains a URL which is a string that identifies a Web component or a static object such as an HTML page or image file The J2EE server converts an HTTP request to an HTTP request object and deliv ers it to the Web component identified by
103. standard and HTTP so client programs can make XML based remote procedure calls RPCs over the Internet JAX RPC also supports WSDL so you can import and export WSDL documents With JAX RPC and a WSDL you can easily interoperate with clients and services running on Java based or non Java based platforms such as NET For example based on the WSDL document a Visual Basic NET client can be configured to use a Web service implemented in Java technology or a Web service can be configured to recognize a VB NET client JAX RPC relies on the HTTP transport protocol Taking that a step further JAX RPC lets you create service applications that combine HTTP with a Java tech nology version of the Secure Socket Layer SSL and Transport Layer Security TLS protocols to establish basic or mutual authentication SSL and TLS ensure message integrity by providing data encryption with client and server authentica tion capabilities Authentication is a measured way to verify whether a party is eligible and able to access certain information as a way to protect against the fraudulent use of a sys tem and or the fraudulent transmission of information Information transported across the Internet is especially vulnerable to being intercepted and misused so configuring a JAX RPC Web service to protect data in transit is very important SOAP with Attachments API for ava SAAJ The SOAP with Attachments API for Java SAAJ is a low level API upon which JAX
104. td bgcolor ffffaa rowspan 2 gt lt c set var price gt lt x out select book price gt lt c set gt lt fmt formatNumber value price type currency gt amp nbsp lt td gt TRANSFORMATION TAGS 169 lt td bgcolor ffffaa rowspan 2 gt lt c url var url value catalog gt lt C iparam name Add value bookId gt lt c url gt lt p gt lt strong gt lt a href lt c out value url gt gt amp nbsp lt fmt message key CartAdd gt amp nbsp lt a gt lt td gt lt tr gt lt tr gt lt td bgcolor ffffFF gt amp nbsp amp nbsp lt fmt message key By gt lt em gt lt x out select book firstname gt amp nbsp lt x out select book surname gt lt em gt lt td gt lt tr gt lt x forEach gt Transformation Tags The transform tag applies a transformation specified by a XSLT stylesheet set by the attribute xs1t to an XML document specified by the attribute xm1 If the xm attribute is not specified the input XML document is read from the tag s body content The param subtag can be used along with transform to set transformation parameters The attributes name and value are used to specify the parameter The value attribute is optional If it is not specified the value is retrieved from the tag s body Intemationalizaton Tags In Internationalizing and Localizing Web Applications page 38 we discussed the how to adapt Web applications to the language and formatti
105. that lets it be selected or rejected for a particular audience The title of the slide on the other hand is part of its contents The visibility heuristic is also satisfied here When the slide is displayed the title is shown but the type of the slide isn t Finally in this example the consumer of the title information is the presentation 235 236 UNDERSTANDING XML audience while the consumer of the type information is the presentation pro gram Normalizing Data In Saving Yourself Some Work page 233 you saw that it is a good idea to define an external entity that you can reference in an XML document Such an entity has all the advantages of a modularized routine changing that one copy affects every document that references it The process of eliminating redundan cies is known as normalizing so defining entities is one good way to normalize your data In an HTML file the only way to achieve that kind of modularity is with HTML links but of course the document is then fragmented rather than whole XML entities on the other hand suffer no such fragmentation The entity reference acts like a macro the entity s contents are expanded in place producing a whole document rather than a fragmented one And when the entity is defined in an external file multiple documents can reference it The considerations for defining an entity reference then are pretty much the same as those you would apply to modularized program
106. that processing associated with winding up may be done and resources may be released The init and destroy methods in this example are callback meth ods local subset That part of the DTD that is defined within the current XML file ABCDEFGHIJKLMNOPQRSTUVWXYZ message driven bean An enterprise bean that is an asynchronous message consumer A message driven bean has no state for a specific client but its instance variables may contain state across the handling of client messages A client accesses a mes sage driven bean by sending messages to the destination for which the bean is a message listener mixed content model A DTD specification that defines an element as containing a mixture of text and one more other elements The specification must start with PCDATA fol lowed by alternate elements and must end with the zero or more asterisk symbol 443 mutual authentication An authentication mechanism employed by two parties for the purpose of proving each other s identity to one another ABCDEFGHIJKLMNOPQRSTUVWXYZ namespace A standard that lets you specify a unique label to the set of element names defined by a DTD A document using that DTD can be included in any other document without having a conflict between element names The elements defined in your DTD are then uniquely identified so that for example the parser can tell when an element called lt name gt should be interpreted accord ing to your DTD r
107. that wish to avoid the more complex aspects of SOAP messaging and for those that find communi cation using the RPC model a good fit The more heavy duty alternative for SOAP messaging the Java API for XML Messaging JAXM is discussed later in this introduction Advanced Features Although JAX RPC is based on the RPC model it offers features that go beyond basic RPC For one thing it is possible to send complete documents and also document fragments In addition JAX RPC supports SOAP message handlers which make it possible to send a wide variety of messages And JAX RPC can be extended to do one way messaging in addition to the request response style of messaging normally done with RPC Another advanced feature is extensible type mapping which gives JAX RPC still more flexibility in what can be sent Using J AX RPC In a typical scenario a business might want to order parts or merchandise It is free to locate potential sources however it wants but a convenient way is through a business registry and repository service such as a Universal Description Dis covery and Integration UDDJ registry Note that the Java API for XML Regis tries JAXR which is discussed later in this introduction offers an easy way to search for Web services in a business registry and repository Web services gen erally register themselves with a business registry and store relevant documents including their WSDL descriptions in its repository After
108. the JSP files definition and servlet mappings a Click the JSP Files property and open the property editor b Note the mappings between the JSP files and the URLs enter cata log bookdetails showcart cashier and receipt Browse the resource references a Select the Resources Property sheet a Click the Resource References property and open the property editor b Note the resource reference named jdbc BookDB The Life Cycle ofa J SP Page A JSP page services requests as a servlet Thus the life cycle and many of the capabilities of JSP pages in particular the dynamic aspects are determined by Java Servlet technology and much of the discussion in this chapter refers to functions described in Chapter 3 When a request is mapped to a JSP page it is handled by a special servlet that first checks whether the JSP page s servlet is older than the JSP page If it is it translates the JSP page into a servlet class and compiles the class During devel opment one of the advantages of JSP pages over servlets is that the build process is performed automatically TRANSLATION AND COMPILATION Translation and Compilaton During the translation phase each type of data in a JSP page is treated differently Template data is transformed into code that will emit the data into the stream that returns data to the client JSP elements are treated as follows e Directives are used to control how the Web container translates and ex
109. the XSL page 191 specification which lets you translate XML tags into other XML tags Doc ument Driven Programming DDP The newest approach to using XML is to construct a document that describes how an application page should look The document rather than simply being displayed consists of references to user interface components and business logic components that are hooked together to create an application on the fly Of course it makes sense to utilize the Java platform for such components Both Java Beans for interfaces and Enterprise Java Beans for business logic can 185 186 UNDERSTANDING XML be used to construct such applications Although none of the efforts undertaken so far are ready for commercial use much preliminary work has already been done Note The Java programming language is also excellent for writing XML process ing tools that are as portable as XML Several Visual XML editors have been writ ten for the Java platform For a listing of editors processing tools and other XML resources see the Software section of Robin Cover s SGML XML Web Page at http www oasis open org cover Binding Once you have defined the structure of XML data using either a DTD or the one of the schema standards a large part of the processing you need to do has already been defined For example if the schema says that the text data in a lt date gt element must follow one of the recognized date forma
110. the finest coffees Established 1914 org setDescription s Create primary contact set name User primaryContact blcm createUser PersonName pName blcm createPersonName Jane Doe primaryContact setPersonName pName Set primary contact phone number TelephoneNumber tNum blcm createTelephoneNumber tNum setNumber 800 555 1212 Collection phoneNums new ArrayListQ phoneNums add tNum primaryContact setTelephoneNumbers phoneNums Set primary contact email address EmailAddress emailAddress blcm createEmai lAddress jane doe TheCoffeeBreak com Collection emailAddresses new ArrayList emai lAddresses add emai lAddress primaryContact setEmai lAddresses emai lAddresses Set primary contact for organization org setPrimaryContact primaryContact MANAGING REGISTRY DATA Adding Classifiations Organizations commonly belong to one or more classifications based on one or more classification schemes taxonomies To establish a classification for an organization using a taxonomy the client first locates the taxonomy it wants to use It uses the BusinessQueryManager to find the taxonomy The findClassificationSchemeByName method takes a set of FindQualifier objects as its first argument but this argument can be null Set classification scheme to NAICS ClassificationScheme cScheme bqm findClassificationSchemeByName null ntis gov naics The client then creates a classifi
111. the groups and or principals recognized by the container to security roles specified in the deployment descriptor Security roles have to be mapped before a component is installed in the server rollback The point in a transaction when all updates to any resources involved in the transaction are reversed root The outermost element in an XML document The element that contains all other elements ABCDEFGHIJKLMNOPQRSTUVWXYZ SAX Simple API for XML An event driven interface in which the parser invokes one of several methods supplied by the caller when a parsing event occurs 447 Events include recognizing an XML tag finding an error encountering a ref erence to an external entity or processing a DTD specification schema A database inspired method for specifying constraints on XML documents using an XML based language Schemas address deficiencies in DTDs such as the inability to put constraints on the kinds of data that can occur in a par ticular field Since schemas are founded on XML they are hierarchical so it is easier to create an unambiguous specification and possible to determine the scope over which a comment is meant to apply Secure Socket Layer SSL A technology that allows Web browsers and Web servers to communicate over a secured connection security attributes A set of properties associated with a principal Security attributes can be associated with a principal by an authentication protocol or by a Java WSDP
112. the servlet is using and save any persistent state The following destroy method releases the database object cre ated in the init method described in Initializing a Servlet page 58 public void destroy bookDB null All of a servlet s service methods should be complete when a servlet is removed The server tries to ensure this by calling the destroy method only after all ser vice requests have returned or after a server specific grace period whichever comes first If your servlet has operations that take a long time to run that is operations that may run longer than the server s grace period the operations could still be running when destroy is called You must make sure that any 80 JAVA SERVLET TECHNOLOGY threads still handling client requests complete the remainder of this section describes how to e Keep track of how many threads are currently running the service method e Provide a clean shutdown by having the destroy method notify long run ning threads of the shutdown and wait for them to complete e Have the long running methods poll periodically to check for shutdown and if necessary stop working clean up and return Tracking Service Requests To track service requests include in your servlet class a field that counts the number of service methods that are running The field should have synchronized access methods to increment decrement and return its value public class ShutdownExample extend
113. thing you need to do is access it as shown in the following line of code You can access each element in separate method calls as was done in Request java or you can access the SOAPBody object using this shorthand version SOAPBody replyBody reply getSOAPPart getEnvelope getBody Next you might print out two blank lines to separate your results from the raw XML message and a third line that describes the text that follows System out printIn System out printin System out print Content extracted from the reply message Now you can begin the process of getting all of the child elements from an ele ment getting the child elements from each of those and so on until you arrive at a text element that you can print out Unfortunately when you extract informa tion from a registry the number of subelements sometimes varies making it dif ficult to know how many levels down the code needs to go And in a test registry there may be multiple entries for the same company name The code drills down through the subelements within the SOAP body and retrieves the name and description of the business The method you use to retrieve child elements is the SOAPElement method getChildElements When you give this method no arguments it retrieves all of the child elements of the element on which it is called If you know the Name object used to name an ele ment you can supply that to getChildElements and retrieve only the ch
114. to find some new coffee suppliers get their wholesale prices and then arrange for orders to be placed as the need arises The Coffee Break can analyze the prices and decide which new coffees it wants to carry and which companies it wants to buy them from Disc overing New Distributors The business manager assigns the task of finding potential new sources of coffee to the company s software engineer She decides that the best way to locate new coffee suppliers is to search a Universal Description Discovery and Integration UDDD registry where The Coffee Break has already registered itself The engineer uses JAXR to send a query searching for wholesale coffee suppli ers The JAXR implementation uses JAXM behind the scenes to send the query to the registry but this is totally transparent to the engineer The UDDI registry will receive the query and apply the search criteria transmit ted in the JAXR code to the information it has about the organizations registered with it When the search is completed the registry will send back information on how to contact the wholesale coffee distributors that met the specified criteria Although the registry uses JAXM behind the scenes to transmit the information the response the engineer gets back is JAXR code Requesting Price Lists The engineer s next step is to request price lists from each of the coffee distribu tors She has obtained a WSDL description for each one which tells her the pr
115. today new Date Date endDate DateHelper addDays today 30 plb new PriceListBeanQ plb setStartDate today plb setEndDate endDate plb setPriceltems pricelItems Ordering Coffee The other kind of message that the Coffee Break server can send to the JAXM distributor is an order for coffee This is done in the placeOrder method of JAX MOrderRequest which follows the DTD coffee order dtd JAXM CLIENT Creating the Order As with the client code for requesting a price list the placeOrder method starts out by creating a SOAPConnection object creating a SOAPMessage object and accessing the message s SOAPEnve lope and SOAPBody objects SOAPConnectionFactory scf SOAPConnectionFactory newInstance SOAPConnection con scf createConnectionQ MessageFactory mf MessageFactory newInstance SOAPMessage msg mf createMessage SOAPPart part msg getSOAPPartQ SOAPEnvelope envelope part getEnvelopeQ SOAPBody body envelope getBody Next the code creates and adds XML elements to form the order As is required the first element is a SOAPBodyElement which in this case is coffee order Name bodyName envelope createName coffee order PO http sonata coffeebreak com SOAPBodyElement order body addBodyE1lement bodyName The application then adds the next level of elements the first of these being orderID The value given to orderID is extracted from the OrderBean object passed t
116. variables defining 121 providing information about 133 135 Struts tag library 115 tag handlers 125 defining scripting vari ables 132 methods 125 simple tag 126 with attributes 127 with bodies 130 tag library descriptors See tag library descriptors tutorial template tag library 115 cxml 198 D data element 216 normalizing 236 processing 185 databases clients 7 EIS tier 5 DDP declaration 181 200 defining text 212 deleteOrganizations method 365 deployer role 17 deployment 254 deployment descriptors 14 web application 26 destroy 79 Detail object 321 DetailEntry object 321 development roles 14 DII 282 doAfterBody 130 document element 216 Document Object Model See DOM Document Driven Programming See DDP doEndTag 126 doFilter 65 66 71 72 doGet 59 doInitBody 130 DOM 189 242 245 267 transforming to an XML Doc ument 248 dom4j 189 doPost 59 doStartTag 126 downloading J2EE SDK ix tutorial ix DrawML 198 DTD 181 190 192 defining attributes 216 defining entities 219 defining namespaces 230 factoring out 237 industry standard 233 limitations 213 normalizing 237 dynamic invocation interface See DII dynamic proxies 280 E EAR files 13 ease of use 251 ebXML 198 256 263 Message Service Specification 256 profile 299 311 registries 348 349 EIS 11 EJB containers 13 electronic business XML See ebXML element 201 empty 203 nested 202 qualifiers 212 root 200 elim
117. web bookdetails jsp uses the form lt jsp setProperty name bookDB property bookId gt RETRIEVING JAVABEANS COMPONENT PROPERTIES 109 whereas bookstore2 web bookdetails jsp uses the form lt bookDB setBookId bookId gt The following fragments from the page bookstore3 web showcart jsp illus trate how to initialize a currency bean with a Locale object and amount deter mined by evaluating request time expressions Because the first initialization is nested in a useBean element it is only executed when the bean is created lt jsp useBean id currency class util Currency scope session gt lt jsp setProperty name currency property locale value lt request getLocale gt gt lt jsp useBean gt lt jsp setProperty name Currency property amount value lt cart getTotal gt gt Retneving JavaBeans Component Properties There are several ways to retrieve JavaBeans component properties Two of the methods the jsp getProperty element and an expression convert the value of the property into a String and insert the value into the current implicit out object e lt jsp getProperty name beanName property propName gt lt beanName getPropName gt For both methods beanName must be the same as that specified for the id attribute in a useBean element and there must be a getPropName method in the JavaBeans component If you need to retrieve the value of a property without converting
118. 100 gt lt b gt Extension lt b gt lt td gt lt td width 100 gt lt b gt Emai 1 lt b gt lt td gt lt tr gt lt List all department members gt lt tlt iterator name member type org Member group lt dept getMembers gt gt lt tr gt lt td gt lt jsp getProperty name member property name gt lt td gt lt td gt lt jsp getProperty name member property phone gt lt td gt lt td gt lt jsp getProperty name member property emai1 gt lt td gt lt tr gt lt tlt iterator gt lt table gt lt body gt Upon selecting the Engineering department from the previous page your browser will display the page in Figure 5 3 Engineering Department Netscape http localhostiteratar listjsp deptName Engineering al Engineering Name Extension Brown Kim 70707 Corelli Jeff 45454 Dan Tina 78787 Harvey Ann 43434 Figure 5 3 Engineering Department Contact Information 140 CUSTOM TAGS IN JSP PAGES Tag Handler The doStartTag method first initializes an iterator from a collection provided as a tag attribute If the iterator contains more elements doStartTag sets the value of the scripting variable to the next element and then sets the return value to EVAL_BODY_INCLUDE to indicate that the body should be evaluated otherwise it ends the iteration by returning SKIP_BODY After the body has been evaluated the doAfterBody method sets
119. 11d6 9e2b 000629dc0a2b Next you specify the mapping from the id of each JAXRConcept element in the default JAXR postal address scheme to the id of its counterpart in the IBM scheme props setProperty javax xml registry semanticEquivalences urn uuid PostalAddressAttributes StreetNumber urn uuid 6eaf4b50 4196 11d6 9e2b 000629dc a2b StreetAddressNumber urn uuid PostalAddressAttributes Street urn uuid 6beaf4b50 4196 11d6 9e2b 000629dc a2b StreetAddress urn uuid PostalAddressAttributes City urn uuid 6eaf4b50 4196 11d6 9e2b 000629dc0a2b City urn uuid PostalAddressAttributes State urn uuid 6eaf4b50 4196 11d6 9e2b 000629dc0a2b State urn uuid PostalAddressAttributes PostalCode urn uuid 6eaf4b50 4196 11d6 9e2b 000629dc0 a2b ZipCode urn uuid PostalAddressAttributes Country urn uuid 6eaf4b50 4196 11d6 9e2b 000629dc a2b Country RUNNING THE CLIENT EXAMPLES 371 After you create the connection using these properties you can create a postal address and assign it to the primary contact of the organization before you pub lish the organization String streetNumber 99 String street Imaginary Ave Suite 33 String city Imaginary City String state NY String country USA String postalCode 00000 String type PostalAddress postAddr blcm createPostalAddress streetNumber street city state country postalCode type Collection postalAddres
120. 241 252 263 347 adding classifications 363 service bindings 363 services 363 architecture 349 capability levels 348 clients 349 implementing 351 submitting data to a regis try 361 creating connections 352 defining taxonomies 366 definition 348 establishing security creden tials 361 finding classification schemes 363 information model 348 organizations creating 361 removing 365 saving 364 provider 349 querying a registry 356 specification 348 specifying postal addresses 369 submitting data to a registry 361 JAX RPC 241 250 defined 269 JavaBeans components 272 overview 250 specification 286 supported types 270 JDBC API 18 JDOM 189 JMS 19 tutorial 11 JNDI 19 259 JSP 267 JSP declarations 95 JSP expressions 98 JSP pages 83 compilation 88 errors 89 creating and using objects 94 creating dynamic content 92 creating static content 92 custom tags See custom tags declarations See JSP declarations eliminating scripting 111 error page 90 examples 27 85 86 114 149 150 execution 90 expressions See JSP expressions finalization 91 forwarding to an error page 90 forwarding to other Web com ponents 100 implicit objects 92 importing classes and packag es 95 importing tag libraries 118 including applets or JavaBeans components 100 including other Web resources 98 initialization 91 JavaBeans components creating 106 retrieving properties 109 setting properties 106 from constants 107 from request param
121. 61 388 THE COFFEE BREAK APPLICATION First the makeConnection method creates a connection to the Registry Server See Establishing a Connection page 351 for more information To do this it first specifies a set of connection properties using the query and publish URLs passed in from the CoffeeRegistry properties file For the Registry Server the query and publish URLs are actually the same Properties props new Properties props setProperty javax xml registry queryManagerURL queryUr1 props setProperty javax xml registry 1lifeCycleManagerURL publishUrl Next the makeConnection method creates the connection using the connection properties ConnectionFactory factory ConnectionFactory newInstance factory setProperties props connection factory createConnection The executePublish method takes three arguments a username a password and an endpoint It begins by obtaining a RegistryService object then a Busi nessQueryManager object and a BusinessLifeCycleManager object which enable it to perform queries and manage data rs connection getRegistryService blcm rs getBusinessLifeCycleManager bqm rs getBusinessQueryManager Because it needs password authentication in order to publish data it then uses the username and password arguments to establish its security credentials PasswordAuthentication passwdAuth new PasswordAuthentication Cusername password toCharArray Set creds
122. 77 78 JAVA SERVLET TECHNOLOGY 3 Select the Session Timeout property and open the property editor 4 Type the timeout period To ensure that an active session is not timed out you should periodically access the session via service methods because this resets the session s time to live counter When a particular client interaction is finished you use the session s invali date method to invalidate a session on the server side and remove any session data The bookstore application s ReceiptServlet is the last servlet to access a cli ent s session so it has responsibility for invalidating the session public class ReceiptServlet extends HttpServlet public void doPost HttpServletRequest request HttpServletResponse response throws ServletException IOException Get the user s session and shopping cart HttpSession session request getSession Payment received invalidate the session session invalidateQ Session Tracking A Web container can use several methods to associate a session with a user all of which involve passing an identifier between the client and server The identifier can be maintained on the client as a cookie or the Web component can include the identifier in every URL that is returned to the client If your application makes use of session objects you must ensure that session tracking is enabled by having the application rewrite URLs whenever the client turns off cookies You do this by
123. 89 190 UNDERSTANDING XML Here are the important differences to understand when choosing between the two e JDOM is somewhat cleaner smaller API Where coding style is an important consideration JDOM is a good choice e JDOM is a Java Community Process JCP initiative When completed it will be an endorsed standard e dom4j is a smaller faster implementation that has been in wide use for a number of years e dom4j is a factory based implementation That makes it easier to modify for complex special purpose applications At the time of this writing JDOM does not yet use a factory to instantiate an instance of the parser although the standard appears to be headed in that direction So with JDOM you always get the original parser That s fine for the majority of applications but may not be appropriate if your application has special needs For more information on JDOM see http www jdom org For more information on dom4j see http dom4j org DTD Document Type Definition The DTD specification is actually part of the XML specification rather than a separate entity On the other hand it is optional you can write an XML docu ment without it And there are a number of Schema Standards page 192 pro posals that offer more flexible alternatives So it is treated here as though it were a separate specification A DTD specifies the kinds of tags that can be included in your XML document and the valid
124. AAJ API the javax xm l soap package It does not need to use the javax xml messaging package because it does not use a messaging provider import javax xml soap import java util import java net URL public class Request public static void main String args try SOAPConnectionFactory scFactory SOAPConnectionFactory newlInstance SOAPConnection con scFactory createConnection MessageFactory factory MessageFactory newInstance SOAPMessage message factory createMessage SOAPPart soapPart message getSOAPPartQ SOAPEnvelope envelope soapPart getEnvelope SOAPHeader header envelope getHeader SOAPBody body envelope getBody header detachNode Name bodyName envelope createName THE UDDIPING EXAMPLE 327 GetLastTradePrice m http wombats ztrade com SOAPBodyElement gltp body addBodyE1ement bodyName Name name envelope createName symbol SOAPElement symbol gltp addChi 1dElement name symbol addTextNodeC SUNW URL endpoint new URL C http wombat ztrade com quotes SOAPMessage response con call message endpoint con close SOAPPart sp response getSOAPPart SOAPEnvelope se sp getEnvelope SOAPBody sb se getBody Iterator it sb getChildElements bodyName SOAPBodyElement bodyElement CSOAPBodyElement it nextQ String lastPrice bodyElement getValueQ System out printC The last price for SUNW is
125. Applications page 39 Open the bookstore URL http localhost 80 bookstore4 enter To review the deployment settings RW N Expand the WEB INF node Select the web xml file Select the Deployment property sheet Browse the JSTL basename context parameter a Click the Context Parameters property and open the property editor b Notice that javax servlet jsp jstl fmt localizationContext is set to messages BookstoreMessages Browse the servlet definition and servlet mappings a Click the Servlets property and open the property editor USING JSTL 151 b Notice that the Dispatcher servlet is implemented by the Dispatcher class and that the URLs enter catalog bookdetails showcart cashier and receipt are mapped to the Dispatcher servlet 6 Browse the tag libraries mapping a Click the Tag Libraries property and open the property editor b Notice that the relative URI template is mapped to WEB INF 1ib template jar 7 Browse the resource references a Select the Resources Property sheet a Click the Resource References property and open the property editor b Note the resource reference named jdbc BookDB Using J SIL JSTL includes a wide variety of tags that naturally fit into discrete functional areas Therefore JSTL is exposed via multiple URIs to clearly show the func tional areas it covers and give each area its own namespace Table 6 1 summa 152 JAVASERVER PAGES STANDARD TAG LIBRARY
126. CE 198 include 73 98 information model JAXR 348 349 init 59 instructions processing 182 204 interfaces BusinessLifeCycleManager 350 356 361 BusinessQueryManager 350 356 Collection 271 Connection 349 352 javax xml messaging Pro viderConnection 296 Organization 361 RegistryObject 349 RegistryService 349 356 SOAPEnve lope 307 interoperability 241 251 invalidate 78 ISO 3166 country codes 357 isThreadSafe 94 isValid 129 J J2EE application clients 7 containers 13 J2EE applications 5 assembler role 16 tiers 5 J2EE clients 7 application clients 7 See also J2EE application clients Web clients 7 See also Web clients web clients 25 See also web clients Web clients versus J2EE appli cation clients 8 J2EE components defined 6 types 6 J2EE Connector technology architecture version 22 J2EE modules 14 J2EE platform 1 5 J2EE SDK downloading ix J2EE server 13 J2EE Technology in Practice 23 J2SE SDK 270 JAAS 22 JAF 20 JAR files See also EJB JAR files Java 2 Platform Enterprise Edi tion See J2EE Java API for XML Messaging See JAXM Java API for XML Processing See JAXP See JAXP Java API for XML Registries See JAXR Java API for XML based RPC See JAX RPC Java Authentication and Authori zation Service See JAAS Java Message Service See JMS Java Naming and Directory Inter face See JNDI Java Naming and Directory Inter INDEX 465 face JNDI API 310 Java Naming and Directory Inter face API Se
127. European and English language character set The default is compressed Unicode UTF 8 standalone Tells whether or not this document references an external entity or an exter nal data type specification see below If there are no external references then yes is appropriate The prolog can also contain definitions of entities items that are inserted when you reference them from within the document and specifications that tell which tags are valid in the document both declared in a Document Type Definition DTD that can be defined directly within the prolog as well as with pointers to external specification files But those are the subject of later tutorials For more information on these and many other aspects of XML see the Recommended Reading list of the w3c XML page at http www w3 org XML Note The declaration is actually optional But it s a good idea to include it when ever you create an XML file The declaration should have the version number at a minimum and ideally the encoding as well That standard simplifies things if the XML standard is extended in the future and if the data ever needs to be localized for different geographical regions Everything that comes after the XML prolog constitutes the document s content 182 UNDERSTANDING XML Processing Instructions An XML file can also contain processing instructions that give commands or information to an application that is processing the XML data P
128. Exchange ICE is a protocol for use by content syndicators and their subscribers It focuses on automating content exchange and reuse both in traditional publishing con texts and in business to business relationships For more information on ICE see http www w3 org TR NOTE ice ebXML Electronic Business with XML This standard aims at creating a modular electronic business framework using XML It is the product of a joint initiative by the United Nations UN CEFACT and the Organization for the Advancement of Structured Information Systems OASIS For more information on ebXML see http www ebxm1 org cxml Commerce XML cxml is a RosettaNet ww rosettanet org standard for setting up interactive online catalogs for different buyers where the pricing and product offerings are company specific Includes mechanisms to handle purchase orders change orders status updates and shipping notifications For more information on cxml see http ww cxm1 org SUMMARY 199 CBL Common Business Library CBL is a library of element and attribute definitions maintained by Com merceNet www commerce net For more information on CBL and a variety of other initiatives that work together to enable eCommerce applications see http www com merce net projects current projects eco wg eCo_Framework_Specifications htm UBL Universal Business Language An OASIS initiative aimed at compiling a standard library of XML
129. HttpServlet class provides methods such as doGet and doPost for handling HTTP specific services This chapter focuses on writing servlets that generate responses to HTTP requests Some knowledge of the HTTP protocol is assumed if you are unfamil iar with this protocol you can get a brief introduction to HTTP in HTTP Overview page 427 The Example Serviets This chapter uses the Duke s Bookstore application to illustrate the tasks involved in programming servlets Table 3 1 lists the servlets that handle each bookstore function Each programming task is illustrated by one or more serv lets For example BookDetailsServlet illustrates how to handle HTTP GET requests BookDetailsServlet and CatalogServlet show how to construct responses and CatalogServlet illustrates how to track session information Table 3 1 Duke s Bookstore Example Servlets Function Enter the bookstore BookStoreServlet Create the bookstore banner BannerServlet Browse the bookstore catalog CatalogServlet CatalogServlet Put a book in a shopping cart BookDetailsServlet Get detailed information on a specific book BookDetailsServlet Display the shopping cart ShowCartServlet Remove one or more books from the shopping cart ShowCartServlet Buy the books in the shopping cart CashierServlet THE EXAMPLE SERVLETS Table 3 1 Duke s Bookstore Example Servlets Continued Receive an acknowledgement for the purchase ReceiptServle
130. I method lookup returns a Java Object you must convert it to a ProviderConnectionFactory object before assigning it to the variable pcFactory Context ctx new InitialContextQ ProviderConnectionFactory pcFactory ProviderConnectionFactory ctx lookupC ProviderABC ProviderConnection pcCon pcFactory createConnection You will use pcCon which represents a connection to your messaging provider to get information about your messaging provider and to send the message you will create in the next section CLIENT WITH A MESSAGING PROVIDER Creating a Message You create all JAXM messages by getting a MessageFactory object and using it to create the SOAPMessage object For the standalone client example you simply used the default MessageFactory object obtained via the method MessageFac tory newInstance However when you are using a messaging provider you obtain the MessageFactory object in a different way Getting a MessageFactory If you are using a messaging provider you create a MessageFactory object by using the method ProviderConnection createMessageFactory In addition you pass it a String indicating the profile you want to use To find out which profiles your messaging provider supports you need to get a ProviderMetaData object with information about your provider This is done by calling the method getMetaData on the connection to your provider Then you need to call the method getSupportedProfiles to get an array of
131. L doc uments using Document Object Model DOM Simple API for XML Parsing SAX and XML Stylesheet Language Transformation XSLT JAXP enables applications to parse and transform XML documents independent of a particular XML processing implementation JAXP also provides namespace support which lets you work with schemas that might otherwise have naming conflicts Designed to be flexible JAXP lets you use any XML compliant parser of XSL processor from within your application and supports the W3C schema You can find information on the W3C schema at this URL http www w3 org XML Schema Java API for XML Registries The Java API for XML Registries JAXR lets you access business and general purpose registries over the Web JAXR supports the ebXML Registry Repository standards and the emerging UDDI specifications By using JAXR developers can learn a single API and get access to both of these important registry technol ogies Additionally businesses submit material to be shared and search for material that others have submitted Standards groups have developed schemas for partic JAVA API FOR XML BASED RPC ular kinds of XML documents and two businesses might for example agree to use the schema for their industry s standard purchase order form Because the schema is stored in a standard business registry both parties can use JAXR to access it Java API for XML Based RPC The Java API for XML based RPC JAX RPC uses the SOAP
132. L pages are not considered Web components Like the client tier and as shown in Figure 1 3 the Web tier might include a JavaBeans component to manage the user input and send that input to enterprise beans running in the business tier for processing Business Components Business code which is logic that solves or meets the needs of a particular busi ness domain such as banking retail or finance is handled by enterprise beans running in the business tier Figure 1 4 shows how an enterprise bean receives data from client programs processes it if necessary and sends it to the enter 10 OVERVIEW prise information system tier for storage An enterprise bean also retrieves data from storage processes it if necessary and sends it back to the client program Web Tier JSP Pages Servlets NEW El f WS Components Optional J2EE Server Figure 1 3 Web Tier and J2EE Applications Business Tier EIS Tier a p gt waa JSP Pages Servlets Entity Beans Session Beans omiaan Message Driven p Beans JavaBeans od J2EE Server Figure 1 4 Business and EIS Tiers There are three kinds of enterprise beans session beans entity beans and mes sage driven beans A session bean represents a transient conversation with a cli ent When the client finishes executing the session bean and its data are gone In contrast an entity bean represents persistent data stored in one row of a database ENTERPRISE INFO
133. List enter HitCounterFilter receipt OrderFilter You can map a filter to one or more Web resources and you can map more than one filter to a Web resource This is illustrated in Figure 3 4 where filter F1 is mapped to servlets 1 S2 and S3 filter F2 is mapped to servlet S2 and filter F3 is mapped to servlets S1 and S2 Figure 3 4 Filter to Servlet Mapping Recall that a filter chain is one of the objects passed to the doFilter method of a filter This chain is formed indirectly via filter mappings The order of the filters in the chain is the same as the order in which filter mappings appear in the Web application deployment descriptor 71 72 JAVA SERVLET TECHNOLOGY When a filter is mapped to servlet S1 the Web container invokes the doFilter method of F1 The doFilter method of each filter in S1 s filter chain is invoked by the preceding filter in the chain via the chain doFilter method Since S1 s filter chain contains filters Fl and F3 F1 s call to chain doFilter invokes the doFilter method of filter F3 When F3 s doFilter method completes control returns to Fl s doFilter method Invoking Other Web Resources Web components can invoke other Web resources in two ways indirect and direct A Web component indirectly invokes another Web resource when it embeds in content returned to a client a URL that points to another Web compo nent In the Duke s Bookstore application most Web components conta
134. ML SOX is a schema proposal that includes extensible data types namespaces and embedded documentation For more information on SOX see http www w3 org TR NOTE SOX Schematron Schema for Object oriented XML An assertion based schema mechanism that allows for sophisticated validation For more information on the Schematron validation mechanism see http www ascc net xml resource schematron schematron html Linking and Presentation Standards Arguably the two greatest benefits provided by HTML were the ability to link between documents and the ability to create simple formatted documents and eventually very complex formatted documents The following standards aim at preserving the benefits of HTML in the XML arena and to adding additional functionality as well XML Linking These specifications provide a variety of powerful linking mechanisms and are sure to have a big impact on how XML documents are used XLink The XLink protocol is a specification for handling links between XML doc uments This specification allows for some pretty sophisticated linking including two way links links to multiple documents expanding links that insert the linked information into your document rather than replacing your document with a new page links between two documents that are cre ated in a third independent document and indirect links so you can point to LINKING AND PRESENTATION STANDARDS an address book rat
135. N TO WEB SERVICES cation within the North American Industry Classification System NAICS Then org which now contains the properties and classifications for The Coffee Break is added to the Collection object orgs Finally orgs is saved by 1cm which will manage the life cycle of the Organization objects contained in orgs RegistryService rs connection getRegistryService BusinessLifeCycleManager lcm rs getBusinessLifeCycleManager BusinessQueryManager bqm rs getBusinessQueryManager Organization org Icm createOrganization The Coffee Break org setDescription Purveyor of only the finest coffees Established 1895 ClassificationScheme cScheme bqm findClassificationSchemeByName ntis gov naics Classification classification Classification lcm createClassification cScheme Snack and Nonalcoholic Beverage Bars 722213 Collection classifications new ArrayListQ classifications add classification org addClassifications classifications Collection orgs new ArrayListQ orgs add org lcm saveOrganizations orgs Searching a Registry A business can also use JAXR to search a registry for other businesses The fol lowing code fragment uses the BusinessQueryManager object bqm to search for The Coffee Break Before bqm can invoke the method findOrganizations the code needs to define the search criteria to be used In this case three of the possi ble six search parameters are suppl
136. Note The empty tag saves you from having to code lt flag gt lt flag gt in order to have a well formed document You can control which tags are allowed to be empty by creating a Document Type Definition or DTD We ll talk about that in a few moments If there is no DTD then the document can contain any kinds of tags you want as long as the document is well formed Comments in XML Files XML comments look just like HTML comments lt message to you yourAddress com from me myAddress com subject XML Is Really Cool gt lt This is a comment gt lt text gt How many ways is XML cool Let me count the ways lt text gt lt message gt WHAT Is XML 181 The XML Prolog To complete this journeyman s introduction to XML note that an XML file always starts with a prolog The minimal prolog contains a declaration that iden tifies the document as an XML document like this lt xml version 1 0 gt The declaration may also contain additional information like this lt xml version 1 0 encoding ISO 8859 1 standalone yes gt The XML declaration is essentially the same as the HTML header lt htm1 gt except that it uses lt gt and it may contain the following attributes version Identifies the version of the XML markup language used in the data This attribute is not optional encoding Identifies the character set used to encode the data ISO 8859 1 is Latin 1 the Western
137. OPERTY SOAPACTION_URI_PROPERTY ENCODING_STYLE_PROPERTY 284 BUILDING WEB SERVICES WITH JAX RPC To learn more about these properties refer to the SOAP and WSDL docu ments listed in Further Information page 286 Specifies the method s return type name and parameter QName QNAME_TYPE_STRING new QName NS_XSD string call setReturnType QNAME_TYPE_STRING call setOperationName new QName BODY_NAMESPACE_VALUE sayHello call addParameter String_1 QNAME_TYPE_STRING ParameterMode IN To specify the return type the program invokes the setReturnType method on the Cal1 object The parameter of setReturnType is a QName object that represents an XML string type The program designates the method name by invoking the setOpera tionName method with a QName object that represents sayHel lo To indicate the method parameter the program invokes the addParameter method on the Call object The addParameter method has three argu ments a String for the parameter name String_1 a QName object for the XML type and a ParameterMode object to indicate the passing mode of the parameter IN 6 Invokes the remote method on the Ca11 object String params Murphy String result String call invoke params The program assigns the parameter value Murphy to a String array params and then executes the invoke method with the String array as an argument Here is the source code for the DIIH
138. PC The following list includes features that JAXM can provide and that RPC including JAX RPC does not generally provide e One way asynchronous messaging e Routing of a message to more than one party e Reliable messaging with features such as guaranteed delivery A SOAPMessage object represents an XML document that is a SOAP message A SOAPMessage object always has a required SOAP part and it may also have one or more attachment parts The SOAP part must always have a SOAPEnvelope object which must in turn always contain a SOAPBody object The SOAPEnve lope object may also contain a SOAPHeader object to which one or more head ers can be added The SOAPBody object can hold XML fragments as the content of the message being sent If you want to send content that is not in XML format or that is an entire XML document your message will need to contain an attachment part in addition to the SOAP part There is no limitation on the content in the attach ment part so it can include images or any other kind of content including XML fragments and documents 257 258 INTRODUCTION TO WEB SERVICES Getting a Connection The first thing a JAXM client needs to do is get a connection either a SOAPCon nection object or a ProviderConnection object Getting a Point to Point Connection A standalone client is limited to using a SOAPConnection object which is a point to point connection that goes directly from the sender to the recipient
139. PIs and other features defined in the J2EE speci fication Product providers are typically operating system database system application server or Web server vendors who implement the J2EE platform according to the Java 2 Platform Enterprise Edition Specification Tool Provider The tool provider is the company or person who creates development assembly and packaging tools used by component providers assemblers and deployers Application Component Provider The application component provider is the company or person who creates Web components enterprise beans applets or application clients for use in J2EE applications 15 16 OVERVIEW Enterprise Bean Developer An enterprise bean developer performs the following tasks to deliver an EJB JAR file that contains the enterprise bean e Writes and compiles the source code e Specifies the deployment descriptor e Bundles the class files and deployment descriptor into an EJB JAR file Web Component Developer A Web component developer performs the following tasks to deliver a WAR file containing the Web component e Writes and compiles servlet source code e Writes JSP and HTML files e Specifies the deployment descriptor for the Web component e Bundles the class jsp htm1 and deployment descriptor files in the WAR file J 2EE Applic ation Client Developer An application client developer performs the following tasks to deliver a JAR file containing the J2EE appli
140. Port to the service name MyHelloService that you enter in the Specify Web Service pane of the New wizard See Creating MyHelloService page 274 The service definition interface MyHelloServiceRPC is created by the IDE when you choose the Generate Client Proxy menu item The source code for the Dynami cProxyHel lo client follows package dynamicproxy import java net URL import javax xml rpc Service import javax xml rpc JAXRPCException import javax xml namespace QName import javax xml rpc ServiceFactory import dynamicproxy MyDynamicGenClient MyHel 1loServiceRPC public class DynamicProxyHello public static void main String args try String UrlString http localhost 80 MyHel loService MyHel loService WSDL String nameSpaceUri urn MyHelloService wsd1 String serviceName MyHelloService String portName MyHelloServiceRPCPort URL helloWsd1Url new URL UrlString ServiceFactory serviceFactory ServiceFactory newInstance Service helloService serviceFactory createService helloWsd1Ur1 new QName nameSpaceUri serviceName MyHelloServiceRPC myProxy MyHelloServiceRPC helloService getPort new QName nameSpaceUri portName MyHelloServiceRPC class System out printIn myProxy sayHelloC Buzz 282 BUILDING WEB SERVICES WITH JAX RPC catch Exception ex ex printStackTrace Building and Running the Dynamic ProxyHello Client Before
141. Product Provider security constraint Determines who is authorized to access a Web resource collection security context An object that encapsulates the shared state information regarding security between two entities security permission A mechanism defined by J2SE to express the programming restrictions imposed on component developers security policy domain A scope over which security policies are defined and enforced by a security administrator A security policy domain has a collection of users or princi pals uses a well defined authentication protocol s for authenticating users or principals and may have groups to simplify setting of security policies security role See role security security technology domain A scope over which the same security mechanism is used to enforce a secu rity policy Multiple security policy domains can exist within a single tech nology domain server certificate Used with HTTPS protocol to authenticate Web applications The certificate can be self signed or approved by a Certificate Authority CA 448 server principal The OS principal that the server is executing as service element A representation of the combination of one or more Connector components that share a single engine component for processing incoming requests servlet A Java program that extends the functionality of a Web server generating dynamic content and interacting with Web applications using a request r
142. Pub lisher saves this key in a text file named orgkey txt The OrgRemover program will read the key from orgkey txt so that it can delete the service See PUBLISHING THE SERVICE IN THE REGISTRY 387 Deleting the Service From the Registry page 391 The source code for the Org Publisher program follows package jaxrpc registry import javax xml registry import java util ResourceBundle import java io public class OrgPublisher public static void main String args ResourceBundle registryBundle ResourceBundle getBundle C jaxrpc registry CoffeeRegistry String queryURL registryBundle getStringC query url String publishURL registryBundle getStringC publish url String username registryBundle getString registry username String password registryBundle getString registry password String endpoint registryBundle getString C endpoint String keyFile registryBundle getString key file JAXRPublisher publisher new JAXRPublisher publisher makeConnection queryURL publishURL String key publisher executePublish username password endpoint try FileWriter out new FileWriter keyFile out write key out flushQ out close catch CIOException ex System out printIn ex getMessage The JAXRPublisher class is almost identical to the sample program JAXRPub lish java which is described in Managing Registry Data page 3
143. R API This tutorial does not describe how to implement a JAXR provider A JAXR pro vider provides an implementation of the JAXR specification that allows access to an existing registry provider such as a UDDI or ebXML registry The implemen tation of JAXR in the Sun ONE Application Server itself is an example of a JAXR provider This tutorial includes several client examples which are described in Running the Client Examples page 371 The examples are in the directory lt INSTALL gt j2eetutorial examples jaxr where lt INSTALL gt is the directory where you installed the tutorial Establishing a Connection The first task a JAXR client must complete is to establish a connection to a regis try Preliminaries Getting Access to a Registry Any user of a JAXR client may perform queries on a registry In order to add data to the registry or to update registry data however a user must obtain per mission from the registry to access it To register with one of the public UDDI version 2 registries go to one of the following Web sites and follow the instruc tions e http test uddi microsoft com Microsoft e http uddi ibm com testregistry registry htm IBM e http udditest sap com SAP These UDDI version 2 registries are intended for testing purposes When you register you will obtain a user name and password You will specify this user name and password for some of the JAXR client example programs You do not have to
144. RMATION SYSTEM TIER table If the client terminates or if the server shuts down the underlying services ensure that the entity bean data is saved A message driven bean combines features of a session bean and a Java Message Service JMS message listener allowing a business component to receive JMS messages asynchronously This tutorial describes entity beans and session beans For information on message driven beans see The Java Message Service Tutorial available at http java sun com products jms tutorial index htm Enterprise Information System Tier The enterprise information system tier handles enterprise information system software and includes enterprise infrastructure systems such as enterprise resource planning ERP mainframe transaction processing database systems and other legacy information systems J2EE application components might need access to enterprise information systems for database connectivity for example J 2EE Containers Normally thin client multitiered applications are hard to write because they involve many lines of intricate code to handle transaction and state management multithreading resource pooling and other complex low level details The com ponent based and platform independent J2EE architecture makes J2EE applica tions easy to write because business logic is organized into reusable components In addition the J2EE server provides underlying services in the form of a con tainer for e
145. RPC depends It enables the production and consumption of mes sages that conform to the SOAP 1 1 specification and SOAP with Attachments note Most developers will not use the SAAJ API but will use the higher level JAX RPC API instead 21 22 OVERVIEW Note Java API for XML Messaging JAXM is not part of J2EE 1 4 Instead you can use JAX RPC and SAAJ to send XML documents over the Web J 2EE Connector Architecture The J2EE Connector architecture is used by J2EE tools vendors and system inte grators to create resource adapters that support access to enterprise information systems that can be plugged into any J2EE product A resource adapter is a soft ware component that allows J2EE application components to access and interact with the underlying resource manager Because a resource adapter is specific to its resource manager there is typically a different resource adapter for each type of database or enterprise information system JAX RPC and the J2EE Connector Architecture are complementary technolo gies for enterprise application integration EAI and end to end business integra tion The J2EE Connector Architecture also provides a performance oriented secure scalable and message based transactional integration of J2EE based Web ser vices with existing EISs that can be either synchronous or asynchronous Exist ing applications and EISs integrated through the J2EE Connector Architecture into the J2EE platform can be
146. SERVICES WITH JAX RPC In the IDE s Explorer a WSDL file icon appears as a blue sphere in the lower left corner of a rectangle A WSDL file is an XML document that describes a particular service WSDL files are important because they decouple the service and client development processes A service provider make its WSDL file available to client developers Using an IDE a client developer specifies the WSDL file and generates the runtime classes needed by the client program See Building and Running the StaticStubHello Client page 278 Note that the client developer has access to the service s WSDL but not to the ser vice s libraries or source code 2 Right click the MyHel loService WSDL and choose Open In the Source Editor scroll down to the bottom of the WSDL file The location attribute of the soap address element should match the property in Specifying the SOAP RPC URL step 2 4 Close the Source Editor Deploying MyHelloService 1 Right click the MyHel loService Web service node and choose Deploy 2 To verify the deployment do the following a Start the Admin Console of the Sun One Application Server 7 b In the left pane of the Admin Console expand these nodes App Server Instances serverl Web Apps The MyHel1loService node should appear beneath Web Apps Creating Web Service Clients with J AX This section shows how to create and run these types of clients e Static stub e Dynamic proxy e D
147. String bookId this bookId bookId public void setDatabase BookDBEJB database this database database public BookDetails getBookDetailsQ throws Exception try return BookDetails database getBookDetai 1s bookId catch BookNotFoundException ex throw ex Finally this version of the example contains an applet to generate a dynamic dig ital clock in the banner See Including an Applet page 100 for a description of the JSP element that generates HTML for downloading the applet The source for the Duke s Bookstore application is located in the lt INSTALL gt j2eetutorial examples web bookstore2 directory To deploy and run the example 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstore2 2 Expand the bookstore2 node 3 Right click the DigitalClock class and choose Compile 4 Right click the WEB INF directory and choose Deploy 88 5 6 JAVASERVER PAGES TECHNOLOGY Set up the PointBase database as described in Accessing Databases from Web Applications page 39 Open the bookstore URL http localhost 80 bookstore2 enter ina browser To review the deployment settings 1 2 Select the web xm1 file 3 4 Browse the listener property Expand the WEB INF node Select the Deployment property sheet a Click the Listeners property and open the property editor b Note that the listener class is listeners ContextListener Browse
148. T XSL Transformation An XML file that controls the transformation of an XML document into another XML document or HTML The target docu ment often will have presentation related tags dictating how it will be ren dered by a browser or other presentation mechanism XSLT was formerly part of XSL which also included a tag language of style flow objects XSLTC A compiling version of XSLT ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFGHIJKLMNOPQRSTUVWXYZ 456 About the Authors Java API for XML Processing Eric Armstrong has been programming and writing professionally since before there were personal computers His production experience includes artificial intelli gence AI programs system libraries real time programs and business applica tions in a variety of languages He works as a consultant at Sun s Java Software division in the Bay Area and he is a contributor to JavaWorld He wrote The JBuilder2 Bible as well as Sun s Java XML programming tutorial For a time Eric was involved in efforts to design next generation collaborative discussion decision systems His learn by ear see the fingering music teaching program is currently on hold while he finishes a weight training book His Web site is http www treelight com Web Applications and Technology Stephanie Bodoff is a staff writer at Sun Microsystems In previous positions she worked as a software engineer on distributed computing and telecommu nications systems and object ori
149. TAXONOMIES IN JAXR CLIENTS b name is the name of the JAXRConcept element c parent is the immediate parent id either the ClassificationScheme id or that of the parent JAXRConcept d code is the JAXRConcept element code value The first JAXRConcept element in the naics xm1 file looks like this all on one line lt JAXRConcept jd uuid COB9FE13 179F 413D 8A5B 5004DB8E5BB2 11 name Agriculture Forestry Fishing and Hunting parent uuid CQB9FE13 179F 413D 8A5B 5004DB8E5BB2 code 11 gt lt JAXRConcept gt 4 To add the user defined taxonomy structure to the JAXR provider specify the system property com sun xm1 registry userTaxonomyFi lenames when you run your client program You can use a lt sysproperty gt tag to set this property in a build xm1 file for a client program Or in your pro gram you can set the property as follows A vertical bar is the file sep arator System setProperty C com sun xml registry userTaxonomyFi lenames c myfi le xxx xml c myfile xxx2 xm1 Specifying Postal Addresses The JAXR specification defines a postal address as a structured interface with attributes for street city country and so on The UDDI specification on the other hand defines a postal address as a free form collection of address lines each of which may also be assigned a meaning To map the JAXR PostalAd dress format to a known UDDI address format you specify the UDDI format as a ClassificationScheme objec
150. The DTD file referenced by this definition is xhtm1 dtd You can either copy that file to your system or modify the SYSTEM identifier in the lt ENTITY gt tag to point to the correct URL e This file is a small subset of the XHTML specification loosely modeled after the Modularized XHTML draft which aims at breaking up the DTD for XHTML into bite sized chunks which can then be combined to create different XHTML subsets for different purposes When work on the mod ularized XHTML draft has been completed this version of the DTD should be replaced with something better For now this version will suffice for our purposes The whole point of using an XHTML based DTD was to gain access to an entity it defines that covers HTML style tags like lt em gt and lt b gt Looking through xhtml dtd reveals the following entity which does exactly what we want lt ENTITY inline PCDATA em b al img br gt This entity is a simpler version of those defined in the Modularized XHTML draft It defines the HTML style tags we are most likely to want to use empha sis bold and break plus a couple of others for images and anchors that we may or may not use in a slide presentation To use the inline entity make the changes highlighted below in your DTD file lt ELEMENT title PCDATA inline gt lt ELEMENT item PCDATA inline item gt These changes replaced the simple PCDATA item with the inline entity It is important to notic
151. The Example Servlets page 48 Handling Enors Any number of exceptions can occur when a servlet is executed The Web con tainer will generate a default page containing the message A Servlet Excep tion Has Occurred when an exception occurs but you can also specify that the container should return a specific error page for a given exception To specify such a page you specify an Error Pages property for the Web application deploy ment descriptor see Error Mappings page 32 Sharing Information Web components like most objects usually work with other objects to accom plish their tasks There are several ways they can do this They can use private helper objects for example JavaBeans components they can share objects that are attributes of a public scope they can use a database and they can invoke USING SCOPE OBJECTS 55 other Web resources The Java Servlet technology mechanisms that allow a Web component to invoke other Web resources are described in Invoking Other Web Resources page 72 Using Scope Objects Collaborating Web components share information via objects maintained as attributes of four scope objects These attributes are accessed with the get set Attribute methods of the class representing the scope Table 3 3 lists the scope objects Table 3 3 Scope Objects Accessible From javax servlet Web components within a Web context See Web context ServletContext Accessing the Web Context page 75 j
152. WEB SERVICES WITH JAXR Click OK Notice that on a Windows system the pathname appears with double backslashes Right click the JAXRPublishPostal file and choose the Execute menu item The program output displays the string value of the key of the new organization Running the J AXRQueryPostal Example Like the JAXRPublishPostal example the JAXRQueryPostal example expects the postal properties file pathname and the UUID string as command line arguments It also expects a query string 1 2 3 D Click the JAXRQueryPostal file in the Filesystems tab In the property window for the file choose the Execution tab Click Arguments then double click the ellipsis to bring up the property editor Enter the pathname of the postal properties file the query string and the UUID string of the classification scheme On a Windows system you must specify the full pathname For example you might specify the fol lowing all on one line Sun AppServer7 docs tutorial examples jaxr postal properties coffee uuid f2be7262 aff2 be76 b3fa ddd3e4e600Ff5 5 Right click the JAXRQueryPostal file and choose the Execute menu item The postal address for the primary contact will appear correctly with the JAXR PostalAddress methods Any postal addresses found that use other postal address schemes will appear as Slot lines If you are using a public registry make sure to follow the instructions in Running the JAXRDelete
153. Web service the interface definition and its imple mentation class The following interface definition is a simple example showing the methods a wholesale coffee distributor might want to make available to its prospective cus tomers Note that a service definition interface extends java rmi Remote and its methods throw a java rmi RemoteException object package coffees import java rmi Remote import java rmi RemoteException public interface CoffeeOrderIF extends Remote public Coffee getPriceListQ throws RemoteException public String orderCoffee String coffeeName int quantity throws RemoteException The method getPriceList returns an array of Coffee objects each of which contains a name field and a price field There is one Coffee object for each of the coffees the distributor currently has for sale The method orderCoffee returns a String that might confirm the order or state that it is on back order The following example shows what the implementation might look like with implementation details omitted Presumably the method getPriceList will query the company s database to get the current information and return the result 253 254 INTRODUCTION TO WEB SERVICES as an array of Coffee objects The second method orderCoffee will also need to query the database to see if the particular coffee specified is available in the quantity ordered If so the implementation will set the internal order process in mo
154. X saving with JAXR 364 376 BusinessLifeCycleManager inter face 350 356 361 See also LifeCycleManager in terface BusinessQueryManager interface 350 356 C call method 308 340 capability levels 348 CBL 199 CDATA versus PCDATA 212 classes AttachmentPart 294 ConnectionFactory 352 javax xml soap SOAPConnec tion 296 SOAPEnve lope 293 SOAPFactory 305 SOAPMessage 293 SOAPPart 293 classification schemes finding with JAXR 363 ISO 3166 357 NAICS 357 377 postal address 367 378 publishing 367 378 removing 380 UNSPSC 357 user defined 366 classifications creating with JAXR 363 client application for a Web service 254 JAXR 349 implementing 351 querying a registry 356 standalone 257 258 301 308 Collection interface 271 com sun xml registry ht tp proxyHost connection property 354 com sun xml registry ht tp proxyPort connection property 354 com sun xml registry ht tps proxyHost connection proper ty 354 com sun xml registry ht tps proxyPassword connection property 355 com sun xml registry ht tps proxyPort connection proper ty 354 com sun xml registry ht tps proxyUserName connection property 355 com sun xml registry userTax onomyFilenames system property 369 com sun xml registry useSOAP connection property 355 comment 200 concepts in user defined classification schemes 366 using to create classifications with JAXR 363 conditional sections 227 connection 295 close 308 creating 352 getting
155. XM Tags example uses JavaServer Pages tags to generate and consume a SOAP message Make sure you have followed the instructions in Changing Server Permissions page 325 before you begin To deploy and run the JAXM Tags example perform the following steps 1 Mount the following filesystem lt INSTALL gt j2eetutorial examples jaxm jaxm tags 2 Specify the following context root for the web module jaxm tags 3 Right click the WEB INF node and choose Deploy from the menu 4 Right click the WEB INF node and choose Execute from the menu If this doesn t work open a web browser and enter the following URL localhost 80 jaxm tags index htm If the page cannot be found make sure the server is running THE JAXM PROVIDER 343 5 A web page with the header JSP Examples appears Click on each of the three links For each a page appears with the requests and responses The J AXM Provider The JAXM Provider is a simple example of a JAXM provider The source files for the JAXM Provider like those for the JAXM Provider Administrator are in the directory lt S1STUDIO_HOME gt jwsdp services Before you deploy the provider use the application server administration tool to add lt S1STUDIO_HOME gt jwsdp common 1lib jaxm runtime jar to the applica tion server classpath suffix and restart the application server To do so 1 Open the URL http localhost 4848 in a browser Select the server node Select the JVM Setti
156. XML documents specified in the DTDs might look like The corresponding XML files for each of the DTDs are as follows e request prices xml e price list xml e coffee order xml e confirm xml Because of the DTDs both parties know ahead of time what to expect in a par ticular kind of message and can therefore extract its content using the JAXM API Code for the server application is in the directory lt INSTALL gt j2eetutorial examples cb jaxm service J AXM Service The JAXM coffee distributor the JAXM server in this scenario provides the response part of the request response paradigm When JAXM messaging is being used the server code is a servlet The core part of each servlet is made up of three javax servlet HttpServlet methods init doPost and onMessage The init and doPost methods set up the response message and the onMessage method gives the message its content JAXM SERVICE Retuming the Price List This section takes you through the servlet PriceListServlet This servlet cre ates the message with the current price list that is returned to the method cal11 invoked in PriceListRequest Any servlet extends a javax servlet class Being part of a Web application this servlet extends HttpServlet It first creates a static MessageFactory object that will be used later to create the SOAPMessage object that is returned Then it declares the MessageFactory object msgFactory which will be used to create a SOAPMessage objec
157. XML specifies a good deal more regularity and consistency For example every tag in a well formed XML document must either have an end tag associated with it or it must end in gt So you might see lt p gt lt p gt or you might see lt p gt but you will never see lt p gt standing by itself The upshot of that requirement is that you never have to program for the weird kinds of cases you see in HTML where for example a lt dt gt tag might be terminated by lt DT gt by another lt DT gt by lt dd gt or by lt d1 gt That makes it a lot easier to write code The XHTML specification is a reformulation of HTML 4 0 into XML The latest information is at http ww w3 org TR xhtm11 195 196 UNDERSTANDING XML Knowledge Standards When you start looking down the road five or six years and visualize how the information on the Web will begin to turn into one huge knowledge base the semantic Web For the latest on the semantic Web visit http www w3 org 2001 sw In the meantime here are the fundamental standards you l want to know about RDF Resource Description Framework RDF is a standard for defining meta data information that describes what a particular data item is and specifies how it can be used Used in conjunction with the XHTML specification for example or with HTML pages RDF could be used to describe the content of the pages For example if your browser stored your ID informatio
158. a SOAPConnection object because it does not need to run in a servlet con tainer like Tomcat or in a J2EE server It is the only kind of connection avail able to a client that does not use a messaging provider The following code fragment creates a SOAPConnection object and then after creating and populating the message uses the connection to send the message The parameter request is the message being sent endpoint represents where it is being sent SOAPConnectionFactory factory SOAPConnectionFactory newlInstance SOAPConnection con factory createConnection create a request message and give it content SOAPMessage response con call request endpoint When a SOAPConnection object is used the only way to send a message is with the method ca11 which transmits its message and then blocks until it receives a reply Because the method call requires that a response be returned to it this type of messaging is referred to as request response messaging A Web service implemented for request response messaging must return a response to any message it receives When the message is an update the response is an acknowledgement that the update was received Such an acknowl edgement implies that the update was successful Some messages may not require any response at all The service that gets such a message is still required to send back a response because one is needed to unblock the ca11 method In this case the response is n
159. a summary of the shopping cart int num cart getNumberOfiItems if num gt 0 gt Expressions are then used to insert the value of num into the output stream and determine the appropriate string to include after the number lt font size 2 gt lt messages getString CartContents gt lt num gt lt num 1 lt messages getString CartItem gt lt messages getString CartItems gt lt font gt Including Contentin a J SP Page There are two mechanisms for including another Web resource in a JSP page the include directive and the jsp include element The include directive is processed when the JSP page is translated into a servlet class The effect of the directive is to insert the text contained in another file either static content or another JSP page in the including JSP page You would probably use the include directive to include banner content copyright infor INCLUDING CONTENT IN A JSP PAGE mation or any chunk of content that you might want to reuse in another page The syntax for the include directive is as follows lt include file filename gt For example all the bookstore application pages include the file banner jsp which contains the banner content with the following directive lt include file banner jsp gt In addition the pages bookstore jsp bookdetails jsp catalog jsp and showcart jsp include JSP elements that create and destroy a database bean with
160. ad either edition of the application server from http wwws sun com software products appsrvr home_appsrvr html To deploy the examples from Sun ONE Studio to Application Server 7 you also need to install the Sun ONE Application Server 7 Plugin into Studio You can get the Plugin from the Studio Update Center or the Application Server 7 installa tion Sun ONE Studio 4 Enterprise Edition for Java with Application Server 7 Tutorial contains information on how to install the Plugin Further Information Each chapter in the tutorial contains pointers to additional resources on the tech nologies described in the chapter For basic information on how to use Sun ONE Studio with Sun ONE Applica tion Server 7 see Sun ONE Studio 4 Enterprise Edition for Java with Appli cation Server 7 Tutorial located at lt S1AS7_HOME gt docs studio tutorial index html For further information on the Sun ONE platform components see the following resources Sun ONE Application Server 7 e Getting Started with Sun ONE Application Server 7 located at lt S1AS7_HOME gt docs getting started index htm e For complete documentation for Sun ONE Application Server 7 go to http docs sun com db coll sl_asse_en Sun ONE Studio 4 Enteprise Edition for ava e Sun ONE Studio 4 Enterprise Edition for Java Tutorial http forte sun com ffj documentation si1s41 slseetut pdf e Sun ONE Studio 4 Enterprise Edition for Java update
161. al error error and warn ing In this exercise you ll make a simple modification to the XML file to intro duce a fatal error Then you ll see how it s handled in the Echo app Note The XML structure you ll create in this exercise is in s ideSampleBad1 xm1 The browsable version is s1ideSamp1eBad1 xm1 htm1 One easy way to introduce a fatal error is to remove the final from the empty item element to create a tag that does not have a corresponding end tag That constitutes a fatal error because all XML documents must by definition be well formed Do the following 1 Copy slideSamp1eQ2 xml1 to slideSampleBad1 xm1 2 Edit slideSamp1eBad1 xm1 and remove the character shown below lt OVERVIEW gt lt slide type all1 gt lt title gt Overview lt title gt lt item gt Why lt em gt WonderWidgets lt em gt are great lt item gt lt item gt lt item gt Who lt em gt buys lt em gt WonderWidgets lt item gt lt slide gt to produce lt item gt Why lt em gt WonderWidgets lt em gt are great lt item gt lt item gt lt item gt Who lt em gt buys lt em gt WonderWidgets lt item gt Now you have a file that you can use to generate an error in any parser any time XML parsers are required to generate a fatal error for this file because the lack of an end tag for the lt item gt element means that the XML structure is no longer well formed SUBSTITUTING AND INSERTING TEXT Subsut
162. al purpose XML docu ment such as you might create with a word processor Textual elements could occur in any order in such a document so specifying ANY makes sense The EMPTY specification says that the element contains no contents So the DTD for e mail messages that let you flag the message with lt flag gt might have a line like this in the DTD lt ELEMENT flag EMPTY gt Referencing the DID In this case the DTD definition is in a separate file from the XML document That means you have to reference it from the XML document which makes the DTD file part of the external subset of the full Document Type Definition DTD for the XML file As you ll see later on you can also include parts of the DTD within the document Such definitions constitute the local subset of the DTD Note The XML written in this section is contained in slideSamp1e5 xm1 The browsable version is s1ideSamp1e05 xm1 htm1 CREATING A DOCUMENT TYPE DEFINITION DTD 215 To reference the DTD file you just created add the line highlighted below to your slideSample xm1 file and save a copy of the file as s ideSamp1e 5 xm1 lt A SAMPLE set of slides gt lt DOCTYPE slideshow SYSTEM slideshow dtd gt lt slideshow Again the DTD tag starts with lt In this case the tag name DOCTYPE says that the document is a slideshow which means that the document consists of the slideshow element and everything within it lt s1lide
163. alls 269 RequestDispatcher 72 request response messaging 257 290 296 394 403 requests 60 appending parameters 100 customizing 67 getting information from 60 retrieving a locale 39 See also HTTP requests required software 1x resource bundles 38 responses 62 buffering output 62 customizing 67 See also HTTP responses setting headers 59 roles development See development roles root element 200 RPC 251 269 S SAAJ 292 SAAJ 1 1 API 290 305 specification 290 297 sample programs JAXR 371 compiling 376 editing properties file 373 setting classpath 375 saveOrganizations method 364 SAX 189 242 267 schema 192 RDF 196 XML 193 Schematron 194 searching registries 264 security credentials for XML registries 361 service bindings adding to an organization with JAXR 363 finding with JAXR 360 service endpoint 255 services adding to an organization with JAXR 363 finding with JAXR 360 Servlet 48 INDEX 471 ServletContext 75 ServletInputStream 60 ServletOutputStream 62 ServletRequest 60 ServletResponse 62 servlets 47 binary data reading 60 writing 62 character data reading 60 writing 62 examples 27 finalization 79 initialization 58 failure 59 life cycle 51 life cycle events handling 52 service methods 59 notifying 81 programming long running 82 tracking service requests 80 sessions 76 associating attributes 76 associating with user 78 invalidating 78 notifying objects associated with 77 setContent meth
164. ame 363 367 findConcepts 359 findOrganization 357 getChildElements 331 javax xml soap SOAPConnec tion call 297 Node getValue 308 ProviderConnection send 297 298 315 saveOrganizations 364 setContent 316 setNamespaceAware 247 setPostalAddresses 371 SOAPConnection call 339 SOAPMessage getAttachments 318 SOAPPart setContent 314 MIME data 223 header 294 mixed content model 213 mustUnderstand attribute 300 N NAICS 377 using to find organizations 358 name local 313 Name object 305 331 namespaces 191 247 305 declaration 247 defining a prefix 231 defining in DTD 230 fully qualified 307 313 prefix 249 307 referencing 231 support 242 using 230 nested elements 212 Node getValue method 308 nodes 292 normalizing data 236 DTDs 237 North American Industry Classifi cation System See NAICS O OASIS 233 241 objects AttachmentPart 315 Detail 321 DetailEntry 321 javax activation DataHan dler 317 javax xml transform Source 314 MessageFactory 259 311 Name 305 331 ProviderConnection 258 297 310 SOAPBody 257 293 305 307 313 SOAPBodyElement 305 307 313 332 SOAPConnection 258 296 302 308 INDEX 469 SOAPElement 306 332 SOAPFault 319 336 SOAPHeader 293 305 312 SOAPHeaderElement 312 SOAPMessage 257 304 311 SOAPPart 294 306 314 one way messaging 257 290 297 Orgainzation for the Advancement of Structured Information Stan dards See OASIS Organization interface 361 organizations crea
165. anager object as the following code fragment demon strates DeclarativeQueryManager dqm rs getDeclarativeQueryManager Query query dqm createQuery Query QUERY_TYPE_SQL SELECT id FROM RegistryEntry WHERE name LIKE Coffee AND majorVersion gt 1 AND CmajorVersion gt 2 OR minorVersion gt 3 BulkResponse response2 dqm executeQuery query The BulkResponse object response2 will contain a value for id a uuid for each entry in RegistryEntry that has Coffee in its name and that also has a version number of 1 3 or greater To ensure interoperable communication between a JAXR client and a registry implementation the messaging is done using JAXM This is done completely behind the scenes so as a user of JAXR you are not even aware of it Sample Scenario The following scenario is an example of how the Java APIs for XML might be used and how they work together Part of the richness of the Java APIs for XML 265 266 INTRODUCTION TO WEB SERVICES is that in many cases they offer alternate ways of doing something and thus let you tailor your code to meet individual needs This section will point out some instances in which an alternate API could have been used and will also give the reasons why one API or the other might be a better choice Scenario Suppose that the owner of a chain of coffee houses called The Coffee Break wants to expand by selling coffee online He instructs his business manager
166. anagerURL https uddi ibm com testregistry protect publishapi With the Sun ONE Application Server implementation of JAXR if the client is accessing a registry that is outside a firewall it must also specify proxy host and port information for the network on which it is running For queries it may need to specify only the HTTP proxy host and port for updates it must specify the HTTPS proxy host and port props setProperty com sun xml registry http proxyHost myhost mydomain props setProperty com sun xml registry http proxyPort 8080 ESTABLISHING A CONNECTION props setProperty com sun xml registry https proxyHost myhost mydomain props setProperty com sun xml registry https proxyPort 8080 The client then sets the properties for the connection factory and creates the con nection connFactory setProperties props Connection connection connFactory createConnection The makeConnection method in the sample programs shows the steps used to create a JAXR connection Setting Connection Properties The implementation of JAXR in the Sun ONE Application Server allows you to set a number of properties on a JAXR connection Some of these are standard properties defined in the JAXR specification Other properties are specific to the implementation of JAXR in the Sun ONE Application Server Table 11 1 and Table 11 2 list and describe these properties Table 11 1 Standard JAXR Connection Properties
167. and dynamic components JSP technology projects all the dynamic capabilities of Java Servlet technology but provides a more natural approach to creating static content The main features of JSP technology are e A language for developing JSP pages which are text based documents that describe how to process a request and construct a response e Constructs for accessing server side objects e Mechanisms for defining extensions to the JSP language JSP technology also contains an API that is used by developers of Web contain ers but this API is not covered in this chapter What Is a J SP Page A JSP page is a text based document that contains two types of text static tem plate data which can be expressed in any text based format such as HTML SVG WML and XML and JSP elements which construct dynamic content A syntax card and reference for the JSP elements are available at http java sun com products jsp technical html syntax 83 84 JAVASERVER PAGES TECHNOLOGY The Web page in Figure 4 1 is a form that allows you to select a locale and dis plays the date in a manner appropriate to the locale Localized Dates Netscape a Eile Edit View Go Bookmarks Tools Window Help CHS Q Q amp http localhost 8000 date index jsp Locale Finnish Finland Euro gt _GetDate Date 8 lokakuuta 2002 Figure 4 1 Localized Date Form The source code for this example is in the docs tutorial exam
168. and put some interesting text in it perhaps something like this lt A SAMPLE copyright gt This is the standard copyright message that our lawyers make us put everywhere so we don t have to shell out a million bucks every time someone spills hot coffee in their lap Finally add the text highlighted below to your slideSample xm1 file to refer ence the external entity and save a copy of the file as s ideSamp1e07 htm1 lt TITLE SLIDE gt lt slide gt lt COPYRIGHT SLIDE gt lt slide type all1 gt lt item gt amp copyright lt item gt lt slide gt 222 UNDERSTANDING XML You could also use an external entity declaration to access a servlet that produces the current date using a definition something like this lt ENTITY currentDate SYSTEM http www example com servlet CurrentDate fmt dd MMM yyyy gt You would then reference that entity the same as any other entity Today s date is amp currentDate When you echo the latest version of the slide presentation with an XML parser here is what you ll see lt slide type all1 gt lt item gt This is the standard copyright message that our lawyers make us put everywhere so we don t have to shell out a million bucks every time someone spills hot coffee in their lap lt item gt lt slide gt You ll notice that the newline which follows the comment in the file is echoed as a character but that the comment itself is i
169. and shopping cart HttpSession session request getSession ShoppingCart cart CShoppingCart session getAttribute cart Determine the total price of the user s books double total cart getTotalQ Notifying Objects That Are Associated witha Session Recall that your application can notify Web context and session listener objects of servlet life cycle events Handling Servlet Life Cycle Events page 52 You can also notify objects of certain events related to their association with a session such as the following e When the object is added to or removed from a session To receive this notification your object must implement the javax http HttpSession BindingListener interface e When the session to which the object is attached will be passivated or acti vated A session will be passivated or activated when it is moved between virtual machines or saved to and restored from persistent storage To receive this notification your object must implement the javax http HttpSessionActivationListener interface Session Management Since there is no way for an HTTP client to signal that it no longer needs a ses sion each session has an associated timeout so that its resources can be reclaimed The timeout period can be accessed with a session s get set MaxI nactiveInterval methods You can also set the time out period in the IDE as follows 1 Select the web xml file of a Web module 2 Select the Deployment tab
170. andchildren A JAXRConcept element may have children but it is not required to do so In all element definitions attribute order and case are significant To add a user defined taxonomy follow these steps 1 Publish the JAXRClassificationScheme element for the taxonomy as a ClassificationScheme object in the registry that you will be accessing For example you can publish the ClassificationScheme object to the Sun ONE Studio internal UDDI Server Registry In order to publish a ClassificationScheme object you must set its name You also give the scheme a classification within a known classification scheme such as uddi org types In the following code fragment the name is the first argument of the LifeCycleManager createClassificationScheme method call ClassificationScheme cScheme blcm createClassificationScheme MyScheme A Classification Scheme ClassificationScheme uddiOrgTypes bqm findClassificationSchemeByName null uddi org types if CuddiOrgTypes null Classification classification blcm createClassification uddiOrgTypes postalAddress categorization postalScheme addClassification classification ExternalLink externalLink blcm createExternalLink http www mycom com myscheme htm1 368 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR My Scheme postalScheme addExternalLink externalLink Collection schemes new ArrayListQ schemes add cScheme BulkResponse br blcm saveClassi
171. arameter value If the parameter is direct it is directly inserted into the response otherwise the request is sent to the parame ter and the response is dynamically included into the overall response public int doEndTag throws JspTagException try if CdirectInclude amp amp parameter null pageContext getOut print parameter getValue else if C parameter null amp amp parameter getValueQ null pageContext include parameter getValueQ catch Exception ex throw new JspTagException ex getMessage return EVAL_PAGE How Is a Tag Handler Invoked The Tag interface defines the basic protocol between a tag handler and a JSP page s servlet It defines the life cycle and the methods to be invoked when the start and end tags are encountered The JSP page s servlet invokes the setPageContext setParent and attribute setting methods before calling doStartTag The JSP page s servlet also guaran tees that release will be invoked on the tag handler before the end of the page How Is A TAG HANDLER INVOKED 147 Here is a typical tag handler method invocation sequence ATag t new ATag setPageContext setParent setAttributel valuel setAttribute2 value2 doStartTagQ doEndTagQ releaseQ tetttttet The BodyTag interface extends Tag by defining additional methods that let a tag handler access its body The interface provides three new methods e setBodyCon
172. arizes where various types of objects are stored and how those objects can be accessed from a JSP page Objects created by the jsp useBean tag are stored as attributes of the scope objects and can be accessed by jsp get set Property tags and in scriptlets and expressions Objects created EXTENDING THE JSP LANGUAGE 111 in declarations and scriptlets are stored as variables of the JSP page s servlet class and can be accessed in scriptlets and expressions A Web Context attribute1 attribute2 j Session JSP Page attribute1 attribute2 Request attribute1 attribute2 j l Page Context Servlet lt declaration gt OE dmm lt scriptlet gt lt expression gt jsp useBean mm jsp getProperty jsp setProperty objecti object2 j attribute1 attribute2 j Figure 4 4 Accessing Objects From a JSP Page Extending the J SP Language You can perform a wide variety of dynamic processing tasks including access ing databases using enterprise services such as e mail and directories and flow control with JavaBeans components in conjunction with scriptlets One of the drawbacks of scriptlets however is that they tend to make JSP pages more diffi cult to maintain Alternatively JSP technology provides a mechanism called custom tags that allows you to encapsulate dynamic functionality in objects that are accessed through extensions to the JSP language Custom tags brin
173. arrangements of those tags You can use the DTD to make sure you don t create an invalid XML structure You can also use it to make sure that the XML structure you are reading or that got sent over the net is indeed valid Unfortunately it is difficult to specify a DTD for a complex document in such a way that it prevents all invalid combinations and allows all the valid ones So constructing a DTD is something of an art The DTD can exist at the front of the document as part of the prolog It can also exist as a separate entity or it can be split between the document prolog and one or more additional entities BASIC STANDARDS However while the DTD mechanism was the first method defined for specifying valid document structure it was not the last Several newer schema specifica tions have been devised You ll learn about those momentarily Namespaces The namespace standard lets you write an XML document that uses two or more sets of XML tags in modular fashion Suppose for example that you created an XML based parts list that uses XML descriptions of parts supplied by other manufacturers online The price data supplied by the subcomponents would be amounts you want to total up while the price data for the structure as a whole would be something you want to display The namespace specification defines mechanisms for qualifying the names so as to eliminate ambiguity That lets you write programs that use information from
174. ary key If the container in which an entity bean is hosted crashes the entity bean its primary key and any remote references survive the crash entity reference A reference to an entity that is substituted for the reference when the XML document is parsed It may reference a predefined entity like amp lt or it may reference one that is defined in the DTD In the XML data the reference could be to an entity that is defined in the local subset of the DTD or to an external XML file an external entity The DTD can also carve out a seg ment of DTD specifications and give it a name so that it can be reused included at multiple points in the DTD by defining a parameter entity 436 error A SAX parsing error is generally a validation error in other words it occurs when an XML document is not valid although it can also occur if the declaration specifies an XML version that the parser cannot handle See also fatal error warning Extensible Markup Language A markup language that makes data portable external entity An entity that exists as an external XML file which is included in the XML document using an entity reference external subset That part of the DTD that is defined by references to external dtd files ABCDEFGHIJKLMNOPQRSTUVWXYZ fatal error A fatal error occurs in the SAX parser when a document is not well formed or otherwise cannot be processed See also error warning filter An object that can transform th
175. at you need a validating parser and a DTD ABCDEFGHIJKLMNOPOQRSTUVWXYZ Xalan An interpreting version of XSLT XHTML An XML lookalike for HTML defined by one of several XHTML DTDs To use XHTML for everything would of course defeat the purpose of XML since the idea of XML is to identify information content not just tell how to display it You can reference it ina DTD which allows you to say for exam ple that the text in an element can contain lt em gt and lt b gt tags rather than being limited to plain text XLink The part of the XLL specification that is concerned with specifying links between documents XLL The XML Link Language specification consisting of XLink and XPointer XML Extensible Markup Language A markup language that allows you to define the tags markup needed to identify the content data and text in XML doc uments It differs from HTML the markup language most often used to present information on the internet HTML has fixed tags that deal mainly with style or presentation An XML document must undergo a transforma tion into a language with style tags under the control of a stylesheet before it can be presented by a browser or other presentation mechanism Two types of style sheets used with XML are CSS and XSL Typically XML is trans formed into HTML for presentation Although tags may be defined as needed in the generation of an XML document a DTD may be used to define the elements allowed in a pa
176. at a time the limit is usually a total of about 10 classification schemes and concepts put together Running the Postal Address Examples Running the postal address examples involves the following steps 1 Specifying the UUID of the classification scheme in the postalcon cepts xm file 2 Specifying the pathname of the postalconcepts xml file in the postal properties file 3 Running the JAXRPublishPostal example 4 Running the JAXRQueryPostal example Specifying the UUID Before you run the postal address examples you need to specify the UUID of the classification scheme in the postalconcepts xm file 1 Click the Running tab in the main window 2 In the Output window tab for the JAXRSaveClassi ficationScheme exam ple select the postal scheme key value from the program output It looks something like this uuid f2be7262 aff2 be76 b3fa ddd3e4e600f5 Right click in the window and choose the Copy menu item 3 Right click the file postalconcepts xm1 and choose the Edit menu item RUNNING THE POSTAL ADDRESS EXAMPLES 4 Wherever you see the string uuid from save replace it with the UUID string you copied in step 2 5 Save and close the file For a given registry you only need to save the classification scheme and edit postalconcepts xml once After you perform those steps you can run the JAXRPublishPostal and JAXRQueryPostal programs multiple times Editing the Properties File Next edit the postal properties f
177. at the body needs to be evaluated again Tag Handler Interacts with the Body If the tag handler needs to interact with the body the tag handler must implement BodyTag or be derived from BodyTagSupport Such handlers typically imple ment the doInitBody and the doAfterBody methods These methods interact with body content passed to the tag handler by the JSP page s servlet Body content supports several methods to read and write its contents A tag han dler can use the body content s getString or getReader methods to extract information from the body and the writeOut out method to write the body contents to an out stream The writer supplied to the writeOut method is obtained using the tag handler s getPreviousOut method This method is used to ensure that a tag handler s results are available to an enclosing tag handler If the body of the tag needs to be evaluated the doStartTag method needs to return EVAL_BODY_BUFFERED otherwise it should return SKIP_BODY doInitBody Method The doInitBody method is called after the body content is set but before it is evaluated You generally use this method to perform any initialization that depends on the body content doAfterBody Method TAGS WITH BODIES 131 The doAfterBody method is called after the body content is evaluated Like the doStartTag method doAfterBody must return an indication of whether to continue evaluating the body Thus if the body should be evaluated again
178. ata gives you some sense of what means how to inter pret it what you should do with it XML is sometimes described as a mechanism for specifying the semantics meaning of the data In the same way that you define the field names for a data structure you are free to use any XML tags that make sense for a given application Naturally though for multiple applications to use the same XML data they have to agree on the tag names they intend to use Here is an example of some XML data you might use for a messaging applica tion lt message gt lt to gt you yourAddress com lt to gt lt from gt me myAddress com lt from gt lt subject gt XML Is Really Cool lt subject gt lt text gt How many ways is XML cool Let me count the ways lt text gt lt message gt Note Throughout this tutorial we use boldface text to highlight things we want to bring to your attention XML does not require anything to be in bold The tags in this example identify the message as a whole the destination and sender addresses the subject and the text of the message As in HTML the lt to gt tag has a matching end tag lt to gt The data between the tag and its matching end tag defines an element of the XML data Note too that the content of the lt to gt tag is entirely contained within the scope of the lt message gt lt message gt tag It is this ability for one tag to contain others that gives XML its ability to represent hi
179. ather than using the definition for an element called name in a different DTD naming context A set of associations between unique atomic people friendly identifiers and objects naming environment A mechanism that allows a component to be customized without the need to access or change the component s source code A container implements the component s naming environment and provides it to the component as a JNDI naming context Each component names and accesses its environment entries using the java comp env JNDI context The environment entries are declaratively specified in the component s deployment descriptor normalization The process of removing redundancy by modularizing as with subroutines and of removing superfluous differences by reducing them to a common denominator For example line endings from different systems are normal ized by reducing them to a single NL and multiple whitespace characters are normalized to one space North American Industry Classification System NAICS A system for classifying business establishments based on the processes they use to produce goods or services notation A mechanism for defining a data format for a non XML document refer enced as an unparsed entity This is a holdover from SGML that creaks a bit The newer standard is to use MIME datatypes and namespaces to prevent naming conflicts 444 ABCDEFGHIJKLMNOPQRSTUVWXYZ OASIS Organization for the Advancement of Structur
180. ati re de contr le des exportations et peuvent tre soumis au droit d autres pays dans le domaine des exportations et importations Les utilisations finales ou utilisateurs finaux pour des armes nucl aires des missiles des armes biologiques et chimiques ou du nucl aire maritime directe ment ou indirectement sont strictement interdites Les exportations ou r exportations vers des pays sous embargo des Etats Unis ou vers des entit s figurant sur les listes d exclusion d exportation am ricaines y compris mais de mani re non exclusive la liste de personnes qui font objet d un ordre de ne pas partic iper d une fa on directe ou indirecte aux exportations des produits ou des services qui sont r gi par la l gislation am ricaine en mati re de contr le des exportations U S Commerce Department s Table of Denial Orders et la liste de ressortissants sp cifiquement d sign s U S Treasury Department of Spe cially Designated Nationals and Blocked Persons sont rigoureusement interdites LA DOCUMENTATION EST FOURNIE EN L ETAT ET TOUTES AUTRES CONDITIONS DEC LARATIONS ET GARANTIES EXPRESSES OU TACITES SONT FORMELLEMENT EXCLUES DANS LA MESURE AUTORISEE PAR LA LOI APPLICABLE Y COMPRIS NOTAMMENT TOUTE GARANTIE IMPLICITE RELATIVE A LA QUALITE MARCHANDE A L APTITUDE A UNE UTILISATION PARTICULIERE OU A L ABSENCE DE CONTREFA ON Chapter 1 Chapter 2 Contents About This Tutorial 0 0 es VI
181. avax servlet Web components handling a request that belongs to Dii http HttpSession the session See Maintaining Client State page 76 subtype of request javax servlet Web components handling the request ServletRequest javax servlet The JSP page that creates the object See Implicit jsp PageContext Objects page 92 56 JAVA SERVLET TECHNOLOGY Figure 3 1 shows the scoped attributes maintained by the Duke s Bookstore application lt u BookStoreServiet Session Attribute gt currency BookDetailsServiet Q _ hitCounterFilter Yc ae CatalogServiet Session Attribute e lt q cart ShowCartServlet a Ga CashierServlet orderFilter ReceiptServlet Figure 3 1 Duke s Bookstore Scoped Attributes Web Context Attributes hitCounter bookDB orderCounter j Contolling Concurrent Access to Shared Resour es In a multithreaded server it is possible for shared resources to be accessed con currently Besides scope object attributes shared resources include in memory data such as instance or class variables and external objects such as files data base connections and network connections Concurrent access can arise in sev eral situations e Multiple Web components accessing objects stored in the Web context e Multiple Web components accessing objects stored in a session e Multiple threads within a Web component accessing instance variables A Web contain
182. aveChangesQ resp setStatus HttpServletResponse SC_OK putHeaders reply getMimeHeaders resp Write out the message on the response stream OutputStream os resp getOutputStream reply writeTo os os flushQ else resp setStatus HttpServletResponse SC_NO_CONTENT catch Exception ex throw new ServletException JAXM POST failed ex getMessage The methods getHeaders and putHeaders are not standard methods in a servlet the way init doPost and onMessage are The method doPost calls getHead ers and passes it the HttpServletRequest object req that the application server passed to it It returns a MimeHeaders object populated with the headers from req static MimeHeaders getHeaders HttpServletRequest req Enumeration enum req getHeaderNames MimeHeaders headers new MimeHeaders while Cenum hasMoreElements String headerName String enum nextElement String headerValue req getHeader headerName Stringlokenizer values new StringTokenizer headerValue while values hasMoreTokens headers addHeader headerName values nextToken trimQ return headers 398 THE COFFEE BREAK APPLICATION The doPost method calls putHeaders and passes it the MimeHeaders object headers which was returned by the method getHeaders The method putHead ers writes the headers in headers to res the second argument passed to it The result is that res the re
183. back gt arbitrary_text lt jsp fallback gt lt jsp plugin gt mman The jsp plugin tag is replaced by either an lt object gt or lt embed gt tag as appro priate for the requesting client The attributes of the jsp plugin tag provide configuration data for the presentation of the element as well as the version of the plug in required The nspluginurl and iepluginur attributes specify the URL where the plug in can be downloaded The jsp param elements specify parameters to the applet or JavaBeans compo nent The jsp fallback element indicates the content to be used by the client browser if the plug in cannot be started either because lt object gt or lt embed gt is not supported by the client or because of some other problem If the plug in can start but the applet or JavaBeans component cannot be found or started a plug in specific message will be presented to the user most likely a pop up window reporting a ClassNotFoundException If the applet or Java Beans component cannot be found most likely it has been packaged incorrectly Client side classes such as applets must be packaged in the root of the Web mod ule not in the WEB INF classes directory So the DigitalClock applet con tained in the bookstore2 application is packaged at the same level as the JSP pages 101 102 JAVASERVER PAGES TECHNOLOGY The Duke s Bookstore page banner jsp that creates the banner displays a dynamic digital clock generated by DigitalCl
184. be familiar with This section also surveys a number of other interesting proposals including the HTML lookalike standard XHTML page 195 and the meta standard for describing the information an XML document contains RDF page 196 There are also standards efforts that extend XML s capabilities such as XLink and XPointer Finally there are a number of interesting standards and standards proposals that build on XML including Synchronized Multimedia Integration Language SMIL page 197 Mathematical Markup Language MathML page 197 Scal able Vector Graphics SVG page 197 and DrawML page 198 as well as a number of eCommerce standards The remainder of this section gives you a more detailed description of these ini tiatives To help keep things straight it s divided into e Basic Standards page 188 e Schema Standards page 192 e Linking and Presentation Standards page 194 e Knowledge Standards page 196 e Standards That Build on XML page 197 Skim the terms once so you know what s here and keep a copy of this document handy so you can refer to it whenever you see one of these terms in something you re reading Pretty soon you ll have them all committed to memory and you ll be at least conversant with XML Basic Standards These are the basic standards you need to be familiar with They come up in pretty much any discussion of XML BASIC STANDARDS SAX Simple API for XML This API was a
185. book information should be retrieved from the database This parameter is saved as the attribute name bid and passed to the param tag Notice that the query tag obtains its data source from the context attribute bookDS set in the context listener lt c set var bid value param Add gt lt sql query var books gt select from PUBLIC books where id lt sql param value bid gt lt sql query gt The update tag is used to update a database row The transaction tag is used to perform a series of SQL statements atomically The JSP page receipt jsp page uses both tags to update the database inventory for each purchase Since a shopping cart can contain more than one book the transaction tag is used to wrap multiple queries and updates First the page establishes that there is sufficient inventory then the updates are performed lt c set var sufficientInventory value true gt lt sql transaction gt lt c forEach var item items sessionScope cart items gt lt c set var book value item item gt lt c set var bookId value book bookId gt lt sql query var books sql select from PUBLIC books where id gt lt sql param value bookId gt lt sql query gt lt jsp useBean id inventory class database BookInventory gt lt c forEach var bookRow begin 0 items books rowsByIndex gt lt jsp useBean id bookRow type java lang Object gt lt jsp setProperty na
186. brary Descriptors A tag library descriptor TLD is an XML document that describes a tag library A TLD contains information about a library as a whole and about each tag con tained in the library TLDs are used by a Web container to validate the tags and by JSP page development tools When you create an tag library in the IDE it creates a TLD file You customize a tag library by right clicking the TLD and choosing customize The code genera tion properties do not appear in the TLD but simply determine the location of TAG LIBRARY DESCRIPTORS generated tag handlers and the tag library JAR The properties of the tag library are listed in Table 5 1 Table 5 1 Tag Library Properties Version The tag library s version JSP Version The JSP specification version that the tag library requires Optional name that could be used by a JSP page authoring tool to create Short name names with a mnemonic value URI A URI that uniquely identifies the tag library Display name Optional name intended to be displayed by tools Small Icon Optional small icon that can be used by tools Large Icon Optional large icon that can be used by tools Description Optional tag specific information liste ner Bement A tag library can specify some classes that are event listeners see Handling Servlet Life Cycle Events page 52 The listeners are listed in the TLD as lis tener elements and the Web container will instantiate the l
187. business documents purchase orders invoices etc that are defined with XML Schema definitions For more information on UBL see http ww oasis open org commit tees ubl Summary XML is becoming a widely adopted standard that is being used in a dizzying variety of application areas Generating XML Data This section also takes you step by step through the process of constructing an XML document Along the way you ll gain experience with the XML compo nents you ll typically use to create your data structures Whiting a Simple XML File You ll start by writing the kind of XML data you could use for a slide presenta tion In this exercise you ll use your text editor to create the data in order to become comfortable with the basic format of an XML file You ll be using this file and extending it in later exercises 200 UNDERSTANDING XML Creating the File Using a standard text editor create a file called slideSample xm1 Note Here is a version of it that already exists s1ideSamp1eQ1 xm1 The brows able version is slideSamp1e 1 xm1 htm1 You can use this version to compare your work or just review it as you read this guide Witting the Declaration Next write the declaration which identifies the file as an XML document The declaration starts with the characters lt which is the standard XML identifier for a processing instruction You ll see other processing instructions later on in this tut
188. bute specified by attribute var In bookstore5 the XML document is parsed and saved to a context attribute in parseBooks jsp which is included by all JSP pages that need access to the document lt c if test applicationScope booklist null gt lt c import url books xml var xm1 gt lt xiparse xml xml var booklist scope application gt lt c if gt The out and set tags parallel the behavior described in Expression Tags page 159 for the XPath local expression language The out tag evaluates an XPath expression on the current context node and outputs the result of the evaluation to the current Jspwriter object The set tag evaluates an XPath expression and sets the result into a JSP scoped attribute specified by attribute var The JSP page bookdetails jsp selects a book element whose id attribute matches the request parameter bookId and sets the abook attribute The out tag then selects the book s title element and outputs the result lt x set var abook select applicationScope booklist books book id param bookId gt lt h2 gt lt x out select abook title gt lt h2 gt As you have just seen x set stores an internal XML representation of a node retrieved using an XPath expression it doesn t convert the selected node into a String and store it Thus x set is primarily useful for storing parts of docu ments for later retrieval If you want to store a String you need to use x out wit
189. c In addition to the property methods a JavaBeans component must define a con structor that takes no parameters The Duke s Bookstore application JSP pages enter jsp bookdetails jsp catalog jsp and showcart jsp use the database BookDB and data base BookDetails JavaBeans components BookDB provides a JavaBeans com ponent front end to the access object BookDBAO Both beans are used extensively by bean oriented custom tags see Custom Tags in JSP Pages page 113 The JSP pages showcart jsp and cashier jsp use cart ShoppingCart to repre sent a user s shopping cart The JSP pages catalog jsp showcart jsp and cashier jsp use the util Currency JavaBeans component to format currency in a locale sensitive manner The bean has two writable properties 1ocale and amount and one read able property format The format property does not correspond to any instance variable but returns a function of the locale and amount properties public class Currency private Locale locale private double amount public Currency locale null amount 0 0 public void setLocale Locale 1 locale 1 public void setAmount double a amount a public String getFormat NumberFormat nf WHY USE A JAVABEANS COMPONENT 105 NumberFormat getCurrencyInstance locale return nf format amount Why Use a JavaBeans Component A JSP page can create and use any type of Java programming language object wit
190. calling the response s encodeURL URL method on all URLs returned by a servlet This method includes the session ID in the URL only if cookies are disabled otherwise it returns the URL unchanged The doGet method of ShowCartServlet encodes the three URLs at the bottom of the shopping cart display page as follows out printInC lt p gt amp nbsp lt p gt lt strong gt lt a href response encodeURL request getContextPath catalog gt messages getStringC ContinueShopping lt a gt amp nbsp amp nbsp amp nbsp FINALIZING A SERVLET 79 lt a href response encodeURL request getContextPath cashier gt messages getString Checkout lt a gt amp nbsp amp nbsp amp nbsp lt a href response encodeURL request getContextPath showcart Clear clear gt messages getString ClearCart lt a gt lt strong gt If cookies are turned off the session is encoded in the Check Out URL as fol lows http localhost 80 bookstorel cashier jsessionid c0o07fszeb1 If cookies are turned on the URL is simply http localhost 80 bookstorel cashier Finalizing a Serviet When a servlet container determines that a servlet should be removed from ser vice for example when a container wants to reclaim memory resources or when it is being shut down it calls the destroy method of the Servlet inter face In this method you release any resources
191. cart jsp displays the number of items in a shopping cart as follows lt c out value sessionScope cart numberOfItems gt The set tag sets the value of an attribute in any of the JSP scopes page request session application If the attribute does not already exist it is created 160 JAVASERVER PAGES STANDARD TAG LIBRARY The JSP scoped attribute can be set either from attribute value lt c set var foo scope Session value gt or from the body of the tag lt c set var foo gt Sheree For example the following sets a page scoped attribute named bookID with the value of the request parameter named Remove lt c set var bookId value param Remove gt If you were using the RT version of the library the statement would be lt c_rt set var bookId value lt request getParameter Remove gt gt To remove a scoped attribute you use the remove tag When the bookstore JSP page receipt jsp is invoked the shopping session is finished so the cart ses sion attribute is removed as follows lt c remove var cart scope session gt The JSTL expression language reduces the need for scripting However page authors will still have to deal with situations where some attributes of non JSTL tags must be specified as expressions in the page s scripting language The stan dard JSP element jsp useBean is used to declare a scripting variable that can be used in a scripting language expression or scrip
192. cation client e Writes and compiles the source code e Specifies the deployment descriptor for the client e Bundles the class files and deployment descriptor into the JAR file Application Assembler The application assembler is the company or person who receives application component JAR files from component providers and assembles them into a JZEE application EAR file The assembler or deployer can edit the deployment descriptor directly or use tools that correctly add XML tags according to interactive selections A software developer performs the following tasks to deliver an EAR file containing the J2EE application e Assembles EJB JAR and WAR files created in the previous phases into a J2EE application EAR file APPLICATION DEPLOYER AND ADMINISTRATOR e Specifies the deployment descriptor for the J2EE application e Verifies that the contents of the EAR file are well formed and comply with the J2EE specification Application Deployer and Administrator The application deployer and administrator is the company or person who con figures and deploys the J2EE application administers the computing and net working infrastructure where J2EE applications run and oversees the runtime environment Duties include such things as setting transaction controls and secu rity attributes and specifying connections to databases During configuration the deployer follows instructions supplied by the applica tion component provider to resolv
193. cation using the classification scheme and a con cept a taxonomy element within the classification scheme For example the following code sets up a classification for the organization within the NAICS taxonomy The second and third arguments of the createClassification method are the name and value of the concept Create and add classification Classification classification blcm createClassification cScheme Snack and Nonalcoholic Beverage Bars 722213 Collection classifications new ArrayList classifications add classification org addClassifications classifications Services also use classifications so you can use similar code to add a classifica tion to a Service object Adding Services and Service Bindings to an Organization Most organizations add themselves to a registry in order to offer services so the JAXR API has facilities to add services and service bindings to an organization Like an Organization object a Service object has a name and a description Also like an Organization object it has a unique key that is generated by the registry when the service is registered It may also have classifications associated with it A service also commonly has service bindings which provide information about how to access the service A ServiceBinding object normally has a description 363 364 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR an access URI and a specification link which provides the li
194. ccess the Internet an intranet or an extranet A Web server hosts Web sites provides support for HTTP and other protocols and executes server side programs such as CGI scripts or servlets that perform certain functions In the J2EE architecture a Web server provides services to a Web container For example a Web container typically relies on a Web server to provide HTTP message handling The J2EE architecture assumes that a Web container is hosted by a Web server from the same vendor so does not specify the contract between these two entities A Web server may host one or more Web containers Web service An application that exists in a distributed environment such as the Internet A Web service accepts a request performs its function based on the request and returns a response The request and the response can be part of the same operation or they can occur separately in which case the consumer does not need to wait for a response Both the request and the response usually take the form of XML a portable data interchange format and are delivered over a wire protocol such as HTTP well formed An XML document that is syntactically correct It does not have any angle brackets that are not part of tags all tags have an ending tag or are them selves self ending and all tags are fully nested Knowing that a document is well formed makes it possible to process it A well formed document may 454 not be valid however To determine th
195. ce list sitting in mem ory The following code fragment adds a new coffee with the name Kona and a price of 13 50 to the price list document Because we want to add the new coffee right before the coffee whose name is Mocha Java the first step is to get a list of the coffee elements and iterate through the list to find Mocha Java 245 246 INTRODUCTION TO WEB SERVICES Using the Node interface included in the org w3c dom package the code then cre ates a Node object for the new coffee element and also new nodes for the name and price elements The name and price elements contain character data so the code creates a Text object for each of them and appends the text nodes to the nodes representing the name and price elements Node rootNode NodeList list document getDocumentElementQ document getElementsByTagName coffee Loop through the list for Cint i 0 i lt list getLengthQ i thisCoffeeNode list item i Node thisNameNode thisCoffeeNode getFirstChildQ if CthisNameNode null continue if CthisNameNode getFirstChildQ null continue if C thisNameNode getFirstChildQ instanceof org w3c dom Text continue String data thisNameNode getFirstChildQ getNodeValue if C data equalsC Mocha Java continue We re at the Mocha Java node Create and insert the new element Node newCoffeeNode document createElement coffee Node newNameNode docu
196. ceListServlet because the web xml file at lt INSTALL gt j2eetutorial examples cb jaxm service WEB INF maps the given endpoint to that servlet Extracting the Price List This section demonstrates 1 retrieving the price list that is contained in response the SOAPMessage object returned by the method ca11 and 2 return ing the price list as a PriceListBean The code creates an empty Vector object that will hold the coffee name and price elements that are extracted from response Then the code uses response to access its SOAPBody object which holds the message s content Notice that the SOAPEnve lope object is not accessed separately because it is not needed for cre ating Name objects as it was in the previous section Vector list new Vector SOAPBody responseBody response getSOAPPart getEnvelope getBodyQ The next step is to retrieve the SOAPBodyElement object The method getCh ildElements returns an Iterator object that contains all of the child elements of the element on which it is called so in the following lines of code it1 con tains the SOAPBodyElement object bodyE1 which represents the price list element Iterator itl responseBody getChi ldElements while Citl hasNextQ SOAPBodyElement bodyEl CSOAPBodyElement it1 nextQ The Iterator object it2 holds the child elements of bodyE1 which represent coffee elements Calling the method next on it2 retrieves the first coffee ele ment in bodyE1 As
197. cedure call is implemented as a request response SOAP message The other key to interoperability is JAX RPC s support for WSDL A WSDL description being an XML document that describes a Web service in a standard way makes the description portable WSDL documents and their uses will be discussed more later Ease of Use Given the fact that JAX RPC is based on a remote procedure call RPC mecha nism it is remarkably developer friendly RPC involves a lot of complicated infrastructure or plumbing but JAX RPC mercifully makes the underlying implementation details invisible to both the client and service developer For example a Web services client simply makes Java method calls and all the inter nal marshalling unmarshalling and transmission details are taken care of auto matically On the server side the Web service simply implements the services it offers and like the client does not need to bother with the underlying implemen tation mechanisms 251 252 INTRODUCTION TO WEB SERVICES Largely because of its ease of use JAX RPC is the main Web services API for both client and server applications JAX RPC focuses on point to point SOAP messaging the basic mechanism that most clients of Web services use Although it can provide asynchronous messaging and can be extended to provide higher quality support JAX RPC concentrates on being easy to use for the most com mon tasks Thus JAX RPC is a good choice for applications
198. chronized void setShuttingDown boolean flag shuttingDown flag protected synchronized boolean isShuttingDown return shuttingDown An example of the destroy method using these fields to provide a clean shut down follows public void destroy Check to see whether there are still service methods running and if there are tell them to stop if CnumServices Q gt 0 setShuttingDown true Wait for the service methods to stop whileCnumServices gt 0 try Thread sleepCinterval catch CInterruptedException e 82 JAVA SERVLET TECHNOLOGY Creating Polite Long Running Methods The final step in providing a clean shutdown is to make any long running meth ods behave politely Methods that might run for a long time should check the value of the field that notifies them of shutdowns and should interrupt their work if necessary public void doPost for i 0 CCi lt lotsOfStuffToDo amp amp isShuttingDown Q i try partOfLongRunningOperation i catch CInterruptedException e Further Information For further information on Java Servlet technology see e Resources listed on the Web site http java sun com prod ucts servlet e The Java Servlet 2 3 Specification A JavaServer Pages Technology Stephanie Bodoff J AVASERVER Pages JSP technology allows you to easily create Web content that has both static
199. class subelement of the tag element The tei class element for IteratorTEI would be as follows lt tei class gt iterator IteratorTEI lt tei class gt Cooperating Tags Tags cooperate by sharing objects JSP technology supports two styles of object sharing The first style requires that a shared object be named and stored in the page con text one of the implicit objects accessible to both JSP pages and tag handlers To access objects created and named by another tag a tag handler uses the page Context getAttribute name scope method 135 136 CUSTOM TAGS IN JSP PAGES In the second style of object sharing an object created by the enclosing tag han dler of a group of nested tags is available to all inner tag handlers This form of object sharing has the advantage that it uses a private namespace for the objects thus reducing the potential for naming conflicts To access an object created by an enclosing tag a tag handler must first obtain its enclosing tag with the static method TagSupport findAncestorWith Class from class or the TagSupport getParent method The former method should be used when a specific nesting of tag handlers cannot be guaran teed Once the ancestor has been retrieved a tag handler can access any statically or dynamically created objects Statically created objects are members of the parent Private objects can also be created dynamically Such objects can be stored in a tag handler with the setValue m
200. coffee addChi ldElement priceName4 price4 addTextNode 5 00 message saveChanges catch Exception e e printStackTraceQ 400 THE COFFEE BREAK APPLICATION return message Retuming the Order Confimation ConfirmationServlet creates the confirmation message that is returned to the call method that is invoked in OrderRequest It is very similar to the code in PriceListServlet except that instead of building a price list its onMessage method builds a confirmation with the order number and shipping date The onMessage method for this servlet uses the SOAPMessage object passed to it by the doPost method to get the order number sent in OrderRequest Then it builds a confirmation message with the order ID and shipping date The shipping date is calculated as today s date plus two days public SOAPMessage onMessage SOAPMessage message SOAPMessage confirmation null try retrieve the orderID element from the message received SOAPBody sentSB message getSOAPPartQ getEnvelope getBodyQ Iterator sentIt sentSB getChildElementsQ SOAPBodyElement sentSBE CSOAPBodyElement sentIt nextQ Iterator sentIt2 sentSBE getChildElements SOAPElement sentSE SOAPElement sentIt2 nextQ get the text for orderID to put in confirmation String sentID sentSE getValueQ create the confirmation message confirmation fac createMessage SOAPPart sp confirmation getSOAPPart SOAPEn
201. com blueprints Accessing Databases from Web Applications Data that is shared between Web components and persistent between invocations of a Web application is usually maintained in a database Web applications use the JDBC 2 0 API to access relational databases In the JDBC API databases are accessed via DataSource objects A DataSource has a set of properties that identify and describe the real world data source that it represents These proper ties include information like the location of the database server the name of the database the network protocol to use to communicate with the server and so on Applications access a data source using a connection and a DataSource object can be thought of as a factory for connections to the particular data source that the DataSource instance represents In a basic DataSource implementation a 40 INTRODUCTION TO WEB APPLICATIONS call to the method DataSource getConnection returns a connection object that is a physical connection to the data source If a DataSource object is registered with a JNDI naming service an application can use the JNDI API to access that DataSource object which can then be used to connect to the data source it represents DataSource objects that implement connection pooling also produce a connec tion to the particular data source that the DataSource class represents The con nection object that the method DataSource getConnection returns is a handle to a PooledC
202. compo nent s deployment settings An enterprise bean module deployment descriptor for example declares transaction attributes and security authorizations for an enterprise bean Because deployment descriptor information is declarative it can be changed without modifying the bean source code At run time the J2EE server reads the deployment descriptor and acts upon the component accord ingly A J2EE module without an application deployment descriptor can be deployed as a stand alone module The four types of J2EE modules are e Enterprise JavaBeans modules contain class files for enterprise beans and an EJB deployment descriptor EJB modules are packaged as JAR files with a jar extension e Web modules contain JSP files class files for servlets GIF and HTML files and a Web deployment descriptor Web modules are packaged as JAR files with a war Web ARchive extension e Resource adapter modules contain all Java interfaces classes native libraries and other documentation along with the resource adapter deployment descriptor Together these implement the Connector architec ture see J2EE Connector Architecture page 22 for a particular EIS Resource adapter modules are packages as JAR files with a rar Resource adapter ARchive extension e Application client modules contain class files and an application client deployment descriptor Application client modules are packaged as JAR files with a jar extension Development Ro
203. ctually a product of collaboration on the XML DEV mailing list rather than a product of the W3C It s included here because it has the same final characteristics as a W3C recommendation You can also think of this standard as the serial access protocol for XML This is the fast to execute mechanism you would use to read and write XML data in a server for example This is also called an event driven protocol because the technique is to register your handler with a SAX parser after which the parser invokes your callback methods whenever it sees a new XML tag or encounters an error or wants to tell you anything else DOM Document Object Model The Document Object Model protocol converts an XML document into a collec tion of objects in your program You can then manipulate the object model in any way that makes sense This mechanism is also known as the random access protocol because you can visit any part of the data at any time You can then modify the data remove it or insert new data J DOM and dom4j While the Document Object Model DOM provides a lot of power for docu ment oriented processing it doesn t provide much in the way of object oriented simplification Java developers who are processing more data oriented struc tures trather than books articles and other full fledged documents frequently find that object oriented APIs like JOOM and dom4j are easier to use and more suited to their needs 1
204. d 1 The Coffee Break server uses JAXM messaging to communicate with one of its distributors It has been dealing with this distributor for some time and has previously made the necessary arrangements for doing request response JAXM messaging The two parties have agreed to exchange four kinds of XML messages and have set up the DTDs those messages will fol low The Coffee Break server uses JAXR to send a query searching for coffee distributors that support JAX RPC to the Registry Server The Coffee Break server requests price lists from each of the coffee distrib utors The server makes the appropriate remote procedure calls and waits for the response which is a JavaBeans component representing a price list The JAXM distributor returns price lists as XML documents Upon receiving the responses the Coffee Break server processes the price lists from the JavaBeans components returned by calls to the distributors The Coffee Break Server creates a local database of distributors When an order is placed suborders are sent to one or more distributors using the distributor s preferred protocol JAX RPC DISTRIBUTOR SERVICE 385 J AX RPC Distributor Service The Coffee Break server is a client of the JAX RPC distributor service To exam ine the code for the service in the IDE mount the lt INSTALL gt j2eetutorial examples cb jaxrpc directory The service sup ports two operations fetching the price list and placing an orde
205. d protocols that provide the functionality for developing multitiered Web based applications Java 2 Platform Micro Edition J2ME A highly optimized Java runtime environment targeting a wide range of con sumer products including pagers cellular phones screenphones digital set top boxes and car navigation systems Java 2 Platform Standard Edition J2SE The core Java technology platform Java API for XML Messaging JAXM An API that provides a standard way to send XML documents over the Inter net from the Java platform It is based on the SOAP 1 1 and SOAP with Attachments specifications which define a basic framework for exchanging XML messages JAXM can be extended to work with higher level messag ing protocols such as the one defined in the ebXML electronic business XML Message Service Specification by adding the protocol s functionality on top of SOAP Java API for XML Processing JAXP An API for processing XML documents JAXP leverages the parser stan dards SAX and DOM so that you can choose to parse your data as a stream 439 of events or to build a tree structured representation of it The latest versions of JAXP also support the XSLT XML Stylesheet Language Transforma tions standard giving you control over the presentation of the data and enabling you to convert the data to other XML documents or to other for mats such as HTML JAXP also provides namespace support allowing you to work with schemas that mi
206. d the world Because 16 bits covers 32 768 codes Unicode is large enough to include all the world s languages with the exception of ideographic languages that have a different character for every concept like Chinese For more info see http www uni code org Universal Description Discovery and Integration UDDI project An industry initiative to create a platform independent open framework for describing services discovering businesses and integrating business ser vices using the Internet as well as a registry It is being developed by a ven dor consortium Universal Standard Products and Services Classification UNSPSC A schema that classifies and identifies commodities It is used in sell side and buy side catalogs and as a standardized account code in analyzing expenditure unparsed entity A general entity that contains something other than XML By its nature an unparsed entity contains binary data URI Uniform Resource Identifier A globally unique identifier for an abstract or physical resource A URL is a kind of URI that specifies the retrieval proto col http or https for Web applications and physical location of a resource host name and host relative path A URN is another type of URI 451 URL Uniform Resource Locator A standard for writing a textual reference to an arbitrary piece of data in the World Wide Web A URL looks like proto col host localinfo where protocol specifies a protocol for fetching t
207. d using the rules associated with the global expres sion language In addition to the standard XPath syntax the JSTL XPath engine supports the following scopes to access Web application data within an XPath expression e foo e param e header e cookie e initParam e pageScope e requestScope e sessionScope e applicationScope These scopes are defined in exactly the same way as their counterparts in the JSTL expression language discussed in Implicit Objects page 156 Table 6 5 shows some examples of using the scopes Table 6 5 Example XPath Expressions sessionScope profile The session scoped attribute named profile The String value of the mycom productId context parameter initParam mycom productId The XML tags are illustrated in another version bookstore5 of the Duke s Bookstore application This version replaces the database with an XML repre sentation books xm1 of the bookstore database To build and install this ver sion of the application follow the directions in The Example JSP Pages page 150 replacing bookstore4 with bookstore5 Since the XML tags require an XPath evaluator which is provided in two librar ies jaxen full jar and saxpath jar included with the JSTL tag library CORE TAGS Core Tags The core XML tags provide basic functionality to easily parse and access XML data The parse tag parses an XML document and saves the resulting object in the scoped attri
208. de The Name object for the 305 306 WEB SERVICES MESSAGING WITH JAXM new SOAPElement object symbol is initialized with only a local name which is allowed for child elements Name name envelope createName symbol SOAPElement symbol gltp addChildElement name symbol addTextNodeC SUNW You might recall that the headers and content in a SOAPPart object must be in XML format The JAXM API takes care of this for you building the appropriate XML constructs automatically when you call methods such as addBodyE lement addChildElement and addTextNode Note that you can call the method addTextNode only on an element such as bodyElement or any child elements that are added to it You cannot call addTextNode on a SOAPHeader or SOAPBody object because they contain elements not text The content that you have just added to your SOAPBody object will look like the following when it is sent over the wire lt SOAP ENV Envelope xmIns SOAP ENV http schemas xmlsoap org soap envelope lt SOAP ENV Body gt lt m GetLastTradePrice xmlns m http wombat ztrade com gt lt symbo1l gt SUNW lt symbo1 gt lt m GetLastTradePrice gt lt SOAP ENV Body gt lt SOAP ENV Envelope gt Let s examine this XML excerpt line by line to see how it relates to your JAXM code Note that an XML parser does not care about indentations but they are generally used to indicate element levels and thereby make it easier for a human reader t
209. default value to use if a value is not specified in the docu ment FIXED fixed Value The value to use If the document specifies any value at all it must be the same Finally save a copy of the DTD as slideshow1b dtd for use when experiment ing with attribute definitions DEFINING ATTRIBUTES AND ENTITIES IN THE DTD 219 Defining Entities in the DTD So far you ve seen predefined entities like amp amp and you ve seen that an attribute can reference an entity It s time now for you to learn how to define enti ties of your own Note The XML you ll create here is contained in slideSampleQ6 xm1 The browsable version is s1ideSamp1eQ6 xm1 htm1 Add the text highlighted below to the DOCTYPE tag in your XML file lt DOCTYPE slideshow SYSTEM slideshow dtd lt ENTITY product WonderWidget gt lt ENTITY products WonderWidgets gt gt The ENTITY tag name says that you are defining an entity Next comes the name of the entity and its definition In this case you are defining an entity named product that will take the place of the product name Later when the product name changes as it most certainly will you will only have to change the name one place and all your slides will reflect the new value The last part is the substitution string that replaces the entity name whenever it is referenced in the XML document The substitution string is defined in quotes which are not included when th
210. different target registries JAXR also enables value added capabili ties beyond those of the underlying registries The current version of the JAXR specification includes detailed bindings between the JAXR information model and both the ebXML Registry and the UDDI version 2 specifications You can find the latest version of the specifica tion at http java sun com xml downloads jaxr htm At this release JAXR implements the level 0 capability profile defined by the JAXR specification This level allows access to both UDDI and ebXML regis tries at a basic level At this release JAXR supports access only to UDDI version 2 registries Currently several public UDDI version 2 registries exist JAXR ARCHITECTURE The Sun ONE Studio internal UDDI Server Registry provides a UDDI version 2 registry that you can use to test your JAXR applications in a private environment The Registry does not support messages defined in the UDDI Version 2 0 Repli cation Specification Several ebXML registries are under development and one is available at the Center for E Commerce Infrastructure Development CECID Department of Computer Science Information Systems The University of Hong Kong HKU For information see http ww cecid hku hk Release PRO9APR2002 htm1 A JAXR provider for ebXML registries is available in open source at http ebxmlrr sourceforge net J AXR Architec ture The high level architecture of JAXR consists of the following
211. ds A DTD makes it possible to validate the structure of relatively simple XML doc uments but that s as far as it goes A DTD can t restrict the content of elements and it can t specify complex rela tionships For example it is impossible to specify with a DTD that a lt heading gt for a lt book gt must have both a lt title gt and an lt author gt while a lt heading gt for a lt chapter gt only needs a lt title gt Ina DTD once you only get to specify the struc ture of the lt heading gt element one time There is no context sensitivity This issue stems from the fact that a DTD specification is not hierarchical For a mailing address that contained several parsed character data PCDATA ele ments for example the DTD might look something like this lt ELEMENT mailAddress name address zipcode gt lt ELEMENT name PCDATA gt lt ELEMENT address PCDATA gt lt ELEMENT zipcode PCDATA gt As you can see the specifications are linear That fact forces you to come up with new names for similar elements in different settings So if you wanted to add another name element to the DTD that contained the lt firstname gt lt mid dleInitial gt and lt lastName gt then you would have to come up with another iden tifier You could not simply call it name without conflicting with the lt name gt element defined for use in a lt mailAddress gt Another problem with the non hierarchical
212. e cutes the JSP page e Scripting elements are inserted into the JSP page s servlet class See JSP Scripting Elements page 95 for details e Elements of the form lt jsp XXX gt are converted into method calls to JavaBeans components or invocations of the Java Servlet API For a JSP page named pageName the source for a JSP page s servlet is kept in the file lt S1AS7_HOME gt domains domainl1 serverl1 applications j2ee modules context_root_n pageName jsp java Both the translation and compilation phases can yield errors that are only observed when the page is requested for the first time If an error occurs while the page is being translated for example if the translator encounters a mal formed JSP element the server will return a ParseException and the servlet class source file will be empty or incomplete If an error occurs while the JSP page is being compiled for example there is a syntax error in a scriptlet the server will return a JasperException and a mes sage that includes the name of the JSP page s servlet and the line where the error occurred Once the page has been translated and compiled the JSP page s servlet for the most part follows the servlet life cycle described in Servlet Life Cycle page 51 1 If an instance of the JSP page s servlet does not exist the container a Loads the JSP page s servlet class b Instantiates an instance of the servlet class c Initializes the servlet instanc
213. e ters 107 from runtime expres INDEX 467 sions 108 using 105 life cycle 88 scripting elements See JSP scripting elements scriptlets See JSP scriptlets setting buffer size 90 shared objects 94 specifying scripting language 95 translation 88 89 enforcing constraints for custom tag at tributes 129 errors 89 JSP scripting elements 95 JSP scriptlets 96 drawbacks 111 JSP tag libraries 112 jsp fallback 101 jsp forward 100 jsp getProperty 109 jsp include 99 jsp param 100 101 jsp plugin 100 jsp setProperty 106 jspDestroy 91 jspInit 91 JTA 19 L linking XML 194 listener classes 52 defining 52 examples 52 468 INDEX listener interfaces 52 local name 313 provider 339 M MathML 197 message accessing elements 304 creating 259 303 311 getting the content 308 populating the attachment part 261 populating the SOAP part 260 sending 262 315 MessageFactory object 259 311 getting 311 messaging one way 257 297 provider 256 297 309 getting a connection 258 when to use 300 request response 257 296 methods addChi 1dElement 305 addClassifications 363 addExternalLink 368 addServiceBindings 364 addServices 364 addTextNode 305 call 308 340 createAttachmentPart 318 createClassification 363 367 createClassificationScheme 367 createExternalLink 367 createOrganization 362 createPostalAddress 371 createService 364 createServiceBinding 364 deleteOrganizations 365 findClassi ficationScheme ByN
214. e The timeZone tag estab 171 172 JAVASERVER PAGES STANDARD TAG LIBRARY lishes the time zone specified via the value attribute to be used by any nested formatDate tags In receipt jsp a pretend ship date is created and then formatted with the formatDate tag lt jsp useBean id now class java util Date gt lt jsp setProperty name now property time value lt now getTime 432000000 gt gt lt fmt message key ShipDate gt lt fmt formatDate value now type date dateStyle full gt SOL Tags The JSTL SQL tags are designed for quick prototyping and simple applications For production applications database operations are normally encapsulated in JavaBeans components Table 6 7 SQL Tags Function Tags setDataSource query dateParam Database param transaction update dateParam param The setDataSource tag is provided to allow you to set data source information for the database You can provide a JNDI name or DriverManager parameters to set the data source information All the Duke s Bookstore pages that have more than one SQL tag use the following statement to set the data source lt sql setDataSource dataSource jdbc BookDB gt SQL Tacs The query tag is used to perform an SQL query that returns a result set For parameterized SQL queries you use a nested param tag inside the query tag In catalog jsp the value of the Add request parameter determines which
215. e as shown here lt SL slideshow xmIns SL http ww example com slideshow gt lt SL s1 ideshow gt This definition sets up SL as a prefix that can be used to qualify the current ele ment name and any element within it Since the prefix can be used on any of the contained elements it makes the most sense to define it on the XML document s root element as shown here Note The namespace URI can contain characters which are not valid in an XML name so it cannot be used as a prefix directly The prefix definition associates an XML name with the URI which allows the prefix name to be used instead It also makes it easier to change references to the URI in the future When the prefix is used to qualify an element name the end tag also includes the prefix as highlighted here lt SL slideshow xmlns SL http www example com slideshow gt lt slide gt lt SL title gt Overview lt SL title gt lt slide gt lt SLis ideshow gt Finally note that multiple prefixes can be defined in the same element as shown here lt SL slideshow xmIns SL http ww example com slideshow xmIns xhtml urn gt lt SL slideshow gt With this kind of arrangement all of the prefix definitions are together in one place and you can use them anywhere they are needed in the document This example also suggests the use of URN to define the xhtm1 prefix instead of an URL That definition would conceivably allow the application
216. e Coffee Break Do not dismiss the output window You ll need its contents in the future Return to the Editing tab to continue running the examples After you run the JAXRPublish program but before you run JAXRDelete you can run JAXRQuery to look up the organization you published Running the J AXRQuery Example To run the JAXRQuery example Click the JAXRQuery file in the Filesystems tab In the property window for the file choose the Execution tab Click Arguments Enter a string in the value field such as coffee Right click the JAXRQuery file in the Filesystems tab and choose the Exe cute menu item nA A U Ne The program searches the registry for organizations whose names contain the string you specified Searching is not case sensitive RUNNING THE JAXRQUERYBYNAICSCLASSIFICATION EXAMPLE 377 Running the J AXRQueryByNAIC SC lassifk ation Example After you run the JAXRPublish program you can also run the JAXRQueryByNA ICSClassification example which looks for organizations that use the Snack and Nonalcoholic Beverage Bars classification the same one used for the orga nization created by JAXRPublish To run the program right click the JAXRQueryByNAICSClassification file in the Filesystems tab and choose the Execute menu item Running the J AXRDelete Example To run the JAXRDelete example you need to provide the key returned by the JAXRPublish program Perform the following steps 1 Click th
217. e HttpSessionListener interface are passed an HttpSessionEvent which contains an HttpSession Table 3 2 Servlet Life Cycle Events Object Listener Interface and Event Class javax servilet ServletContextListener and ServletContextEvent Initialization and destruction Web context See Accessing the Web Context page 75 Attribute added removed or replaced javax servilet ServletContextAttributeListener and ServletContextAttributeEvent Session See Maintaining Cli ent State page 76 Creation invalidation and timeout javax servlet http HttpSessionListener and HttpSessionEvent Attribute added removed or replaced javax servlet http HttpSessionAttributeListener and HttpSessionBindingEvent The listeners ContextListener class creates and removes the database helper and counter objects used in the Duke s Bookstore application The meth HANDLING SERVLET LIFE CYCLE EVENTS 53 ods retrieve the Web context object from ServletContextEvent and then store and remove the objects as servlet context attributes import database BookDB import javax servlet import util Counter public final class ContextListener implements ServletContextListener private ServletContext context null public void contextInitialized ServletContextEvent event context event getServletContextQ try BookDB bookDB new BookDB context setAttributeC bookDB bookDB catch Exception ex
218. e JNDI Java Servlet technology 18 See also servlets Java Transaction API See JTA JavaBeans Activation Framework See JAF JavaBeans components 8 272 benefits of using 105 creating in JSP pages 106 design conventions 103 in WAR files 28 methods 104 properties 103 retrieving in JSP pages 109 setting in JSP pages 106 using in JSP pages 105 JavaMail API 20 JavaServer Pages See JSP JavaServer Pages JSP technolo gy 18 See also JSP pages javax activation DataHandler object 317 javax servlet 48 javax servlet http 48 javax xml messaging package 290 javax xml messaging Provider Connection interface 296 javax xml registry package 349 javax xml registry infomodel package 349 javax xml registry 1lifeCycleM anagerURL connection property 466 INDEX 353 javax xml registry postalAd dressScheme connection property 354 370 javax xml registry queryMan agerURL connection property 353 javax xml registry securi ty authenticationMethod connec tion property 354 javax xml registry seman ticEquivalences connection prop erty 353 370 javax xml registry ud di maxRows connection property 354 javax xm1 soap package 290 javax xml soap SOAPConnection class 296 javax xml soap SOAPConnec tion call method 297 javax xm1 transform package 248 javax xml transform Source ob ject 314 JAXM 241 252 256 289 1 0 specification 290 API 290 Javadoc documentation 299 JAXM 1 1 specification 290 JAXP 20 241 314 JAXR
219. e Running tab in the main window 2 In the Output window tab for the JAXRPublish example select the organi zation key value from the program output It looks something like 2 2827a b1f2 c282 3fd27a5c1893 Right click in the window and choose the Copy menu item Click the JAXRDelete file in the Filesystems tab In the property window for the file choose the Execution tab Click Arguments Paste the key string you copied in step 2 into the value field Right click the JAXRDelete file in the Filesystems tab and choose the Exe cute menu item NYDN FB WW The program deletes the specified organization from the registry Running the J AXRQueryByWSDILC lassific ation Example To run the JAXRQueryByWSDLClassification example right click the file in the Filesystems tab and choose the Execute menu item 378 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR This example returns many results from the public registries and is likely to run for several minutes Publishing a Classification Scheme In order to publish organizations with postal addresses to public registries you must publish a classification scheme for the postal address first To run the JAXRSaveClassificationScheme program right click the file in the Filesystems tab and choose the Execute menu item The program returns a UUID string which you will use in the next section The public registries allow you to own more than one classification scheme
220. e by calling the jspInit method 2 The container invokes the _jspService method passing a request and response object If the container needs to remove the JSP page s servlet it calls the jspDestroy method 89 90 JAVASERVER PAGES TECHNOLOGY Execution You can control various JSP page execution parameters by using page directives The directives that pertain to buffering output and handling errors are discussed here Other directives are covered in the context of specific page authoring tasks throughout the chapter Buffering When a JSP page is executed output written to the response object is automati cally buffered You can set the size of the buffer with the following page direc tive lt page buffer none xxxkb gt A larger buffer allows more content to be written before anything is actually sent back to the client thus providing the JSP page with more time to set appropriate status codes and headers or to forward to another Web resource A smaller buffer decreases server memory load and allows the client to start receiving data more quickly Handling Enors Any number of exceptions can arise when a JSP page is executed To specify that the Web container should forward control to an error page if an exception occurs include the following page directive at the beginning of your JSP page lt page errorPage f7Je_name gt The Duke s Bookstore application page initdestroy jsp contains the directive
221. e collection s member type so that the IDE can gen erate a serializer for the member In this example the getPriceList method returns a PriceListBean a collec tion made up of PriceItemBean components The placeOrdermethod passes an OrderBean parameter which contains a collection of LineItemBean compo nents To specify serializers for LineItemBean and PriceItemBean perform these steps 1 Right click the Web service node for Supp1ierService a cube containing a sphere and choose Properties 2 In the properties sheet choose Serialization Classes and open the proper ties editor 3 In the properties editor add the beans LineItemBean and beans Pri ceItemBean classes 4 Click OK to close the properties editor 5 Close the properties sheet 417 418 THE COFFEE BREAK APPLICATION Generating the Service s WSDL File Senializers and other Helper Classes To generate these files and classes right click the Web service node for Supp1i erService and choose Generate Web Service The IDE creates the following e The SupplierService WSDL file represented by a rectangle with a sphere in the lower left corner e Serializers for the JavaBeans components placing these serializers in beans package e The SupplierServiceGenServer package which contains the other seri alizers and the helper classes Deploying the J AX RPC Service Right click the Web service node for SupplierService a cube containing a sphere and cho
222. e context path or the servlet path If the context path is catalog and for the aliases listed in Table 3 4 Table 3 5 gives some examples of how the URL will be broken down Table 3 4 Aliases Paten ferme LawnServlet JSPServlet Table 3 5 Request Path Elements Request Path Servlet Path Path Info catalog lawn index htm1 awn index html catalog help feedback jsp help feedback jsp null Query strings are composed of a set of parameters and values Individual param eters are retrieved from a request with the getParameter method There are two ways to generate query strings e A query string can explicitly appear in a Web page For example an HTML page generated by the CatalogServlet could contain the link lt a href bookstorel catalog Add 101 gt Add To Cart lt a gt Cata logServlet extracts the parameter named Add as follows String bookId request getParameter Add e A query string is appended to a URL when a form with a GET HTTP method is submitted In the Duke s Bookstore application CashierServ let generates a form then a user name input to the form is appended to the URL that maps to ReceiptServlet and finally ReceiptServlet extracts the user name using the getParameter method 61 62 JAVA SERVLET TECHNOLOGY Constructing Responses A response contains data passed between a server and the client All responses implement the ServletResponse interface This interface defines me
223. e external dependencies specify security set tings and assign transaction attributes During installation the deployer moves the application components to the server and generates the container specific classes and interfaces A deployer system administrator performs the following tasks to install and con figure a J2EE application e Adds the J2EE application EAR file created in the preceding phase to the J2EE server e Configures the J2EE application for the operational environment by mod ifying the deployment descriptor of the J2EE application e Verifies that the contents of the EAR file are well formed and comply with the J2EE specification e Deploys installs the J2EE application EAR file into the J2EE server J 2EE APIs The Sun ONE Application Server provides the following APIs to be used in J2EE applications Enterprise J avaBeans Technology An Enterprise JavaBeans EJB component or enterprise bean is a body of code with fields and methods to implement modules of business logic You can 17 18 OVERVIEW think of an enterprise bean as a building block that can be used alone or with other enterprise beans to execute business logic on the J2EE server There are three kinds of enterprise beans session beans entity beans and mes sage driven beans Enterprise beans often interact with databases One of the benefits of entity beans is that you do not have to write any SQL code or use the JDBC API directl
224. e gt 1 56 lt Price gt lt Order gt lt Order gt lt Product gt Peach lt Product gt lt Price gt 1 48 lt Price gt lt Order gt lt PO PurchaseLineItems gt Adding Content to the SOAPPart Object If the content you want to send is in a file JAXM provides an easy way to add it directly to the SOAPPart object This means that you do not access the SOAPBody object and build the XML content yourself as you did in the previous section To add a file directly to the SOAPPart object you use a javax xm trans form Source object from JAXP the Java API for XML Processing There are three types of Source objects SAXSource DOMSource and StreamSource A StreamSource object holds content as an XML document SAXSource and DOM Source objects hold content along with the instructions for transforming the content into an XML document The following code fragment uses JAXP API to build a DOMSource object that is passed to the SOAPPart setContent method The first two lines of code get a ADDING ATTACHMENTS DocumentBuilderFactory object and use it to create the DocumentBuilder object builder Then builder parses the content file to produce a Document object which is used to initialize a new DOMSource object DocumentBuilderFactory dbFactory DocumentBui lderFactory newInstanceQ DocumentBuilder builder dbFactory newDocumentBui lderQ Document doc builder parse file music order soap xml DOMSource domSource new DOMSou
225. e header and or content of a request or response Filters differ from Web components in that they usually do not themselves create responses but rather they modify or adapt the requests for a resource and modify or adapt responses from a resource A filter should not have any dependencies on a Web resource for which it is acting as a filter so that it can be composable with more than one type of Web resource filter chain A concatenation of XSLT transformations in which the output of one trans formation becomes the input of the next form based authentication An authentication mechanism in which a Web container provides an applica tion specific form for logging in This form of authentication uses Base64 encoding and can expose user names and passwords unless all connections are over SSL 437 ABCDEFGHIJKLMNOPQRSTUVWXYZ general entity An entity that is referenced as part of an XML document s content as dis tinct from a parameter entity which is referenced in the DTD A general entity can be a parsed entity or an unparsed entity group An authenticated set of users classified by common traits such as job title or customer profile Groups are also associated with a set of roles and every user that is a member of a group inherits all of the roles assigned to that group ABCDEFGHIJKLMNOPQRSTUVWXYZ Host element A representation of a virtual host HTML Hypertext Markup Language A markup language for hypertext documents on the In
226. e of a SOAP message with no attachments Except for the SOAP header all the parts listed are required I SOAP message A SOAP part 1 SOAP envelope a SOAP header optional b SOAP body MESSAGES SOAPMessage an XML document SOAPEnvelope SOAP Hes hemder Aeaedier ees SOAP Paull opilonmali Figure 10 1 SOAPMessage Object with No Attachments The SAAJ API provides the SOAPMessage class to represent a SOAP message SOAPPart to represent the SOAP part SOAPEnvelope to represent the SOAP envelope and so on When you create a new SOAPMessage object it will automatically have the parts that are required to be in a SOAP message In other words a new SOAPMessage object has a SOAPPart object that contains a SOAPEnve lope object The SOAPEn velope object in turn automatically contains an empty SOAPHeader object fol lowed by an empty SOAPBody object If you do not need the SOAPHeader object which is optional you can delete it The rationale for having it automatically included is that more often than not you will need it so it is more convenient to have it provided The SOAPHeader object may contain one or more headers with information about the sending and receiving parties and about intermediate destinations for the message Headers may also do things such as correlate a message to previous messages specify a level of service and contain routing and delivery informa tion The SOAPBody object which always f
227. e program invokes the createService method of a ServiceFactory object The parameter of the createService method is a QName object that represents the name of the service MyHel loService The WSDL file specifies this name as follows lt service name MyHel loService gt 2 From the Service object creates a Call object QName port new QName qnamePort Call call service createCall port A Call object supports the dynamic invocation of the remote procedures of a service To get a Call object the program invokes the Service object s createCall method The parameter of createCall is a QName object that represents the service definition interface MyHel loService RPC In the WSDL file the name of this interface is designated by the port Type element lt portType name MyHel 1loServiceRPC gt 3 Sets the target endpoint address of the Ca11 object call setTargetEndpointAddress endpoint This address is the URL of the service For a static stub client the IDE refers to the endpoint address as the SOAP RPC URL In the WSDL file this address is specified by the lt soap address gt element lt service name MyHel loService gt lt port name MyHel loServiceRPCPort binding tns MyHel loServiceRPCBinding gt lt soap address location http localhost 80 MyHel loService MyHel loSer vice gt lt port gt lt service gt 4 Sets these properties on the Call object SOAPACTION_USE_PR
228. e text is inserted into the document Just for good measure we defined two versions one singular and one plural so that when the marketing mavens come up with Wally for a product name you will be prepared to enter the plural as Wallies and have it substituted correctly Note Truth be told this is the kind of thing that really belongs in an external DTD That way all your documents can reference the new name when it changes But hey this is an example 220 UNDERSTANDING XML Now that you have the entities defined the next step is to reference them in the slide show Make the changes highlighted below to do that lt slideshow title WonderWwidget amp product Slide Show lt TITLE SLIDE gt lt slide type all1 gt lt title gt Wake up to Wenderwidgets amp products lt title gt lt slide gt lt OVERVIEW gt lt slide type all1 gt lt title gt Overview lt title gt lt item gt Why lt em gt Wenderwidgets amp products lt em gt are great lt item gt lt item gt lt item gt Who lt em gt buys lt em gt Wonderwidgets amp products lt item gt lt slide gt The points to notice here are that entities you define are referenced with the same syntax amp entityName that you use for predefined entities and that the entity can be referenced in an attribute value as well as in an element s contents When you echo this version of the file with an XML parser here is the k
229. e that PCDATA is first in the inline entity and that inline is first wherever we use it That is required by XML s definition of a mixed content DEFINING PARAMETER ENTITIES AND CONDITIONAL SECTIONS 227 model To be in accord with that model you also had to add an asterisk at the end of the title definition Save the DTD as slideshow2 dtd for use when experimenting with parameter entities Note The Modularized XHTML DTD defines both inline and Inline entities and does so somewhat differently Rather than specifying PCDATA em b al img Br their definitions are more like PCDATA em b a img Br Using one of those def initions therefore looks more like this lt ELEMENT title Inline gt Conditional Sections Before we proceed with the next programming exercise it is worth mentioning the use of parameter entities to control conditional sections Although you can not conditionalize the content of an XML document you can define conditional sections in a DTD that become part of the DTD only if you specify include If you specify ignore on the other hand then the conditional section is not included Suppose for example that you wanted to use slightly different versions of a DTD depending on whether you were treating the document as an XML docu ment or as a SGML document You could do that with DTD definitions like the following someExternal dtd lt INCLUDE XML only definitions gt lt IGNORE
230. e value field Right click the JAXRDeleteScheme file in the Filesystems tab and choose the Execute menu item NYDN FW The program deletes the specified classification scheme from the registry Getting a List of Your Registry Objects To get a list of the objects you own in the registry both organizations and classi fication schemes run the JAXRGetMyObjects program Right click the file in the Filesystems tab and choose the Execute menu item If you run this program with the Registry Server it returns all the standard UDDI taxonomies provided with the Registry Server not just the objects you have cre ated 381 382 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR Stopping the Intemal UDDI Server Registry If you started the internal UDDI Server Registry perform the following steps after you have finished using the examples 1 Select the Runtime tab of the Explorer 2 Expand the UDDI Server Registry node 3 Right click the Internal UDDI Registry node and choose the Stop Server menu item Further Information For more information about JAXR registries and Web services see the follow ing e Java Specification Request JSR 93 JAXR 1 0 http jcp org jsr detail 093 jsp e JAXR home page http java sun com xml jaxr index htm e Universal Description Discovery and Integration UDDIJ project http www uddi org e ebXML http www ebxml org e Open Source JAXR Provider for ebXML Registries htt
231. e1 1o client package dij import javax xml rpc Call import javax xml rpc Service import javax xml rpc JAXRPCException import javax xml namespace QName import javax xml rpc ServiceFactory import javax xml rpc ParameterMode DYNAMIC INVOCATION INTERFACE DII CLIENT EXAMPLE 285 public class DIIHello private static String qnameService MyHelloService private static String qnamePort MyHelloServiceRPC private static String endpoint http localhost 80 MyHel loService MyHel loService private static String BODY_NAMESPACE_VALUE urn MyHelloService wsd1 private static String ENCODING_STYLE_PROPERTY Javax xml rpc encodingstyle namespace uri private static String NS_XSD http www w3 org 2001 XMLSchema private static String URI_ENCODING http schemas xmlsoap org soap encoding public static void main String args try ServiceFactory factory ServiceFactory newlInstance Service service factory createService new QName qnameSer vice QName port new QName qnamePort Call call service createCall port call setTargetEndpointAddress endpoint call setProperty Cal1 SOAPACTION_USE_PROPERTY new Boolean true call setProperty Cal1 SOAPACTION_URI_PROPERTY call setProperty CENCODING_STYLE_PROPERTY URI_ENCODING QName QNAME_TYPE_STRING new QName NS_XSD string call setReturnType QNAME_TYPE_STRING
232. ean and can be deter mined at runtime The following isValid method checks that the value of attr is a valid Boolean value Note that since the value of attr1 can be com puted at runtime isValid must check whether the tag user has chosen to pro vide a runtime value public class TwaTEI extends TagExtraInfo public boolean isValid Tagdata data Object o data getAttributeC attr1 if Co null amp amp o TagData REQUEST_TIME_VALUE if CCCString o toLowerCase equals true CString o toLowerCase equalsC false return true else return false else return true 129 130 CUSTOM TAGS IN JSP PAGES Tags with Bodies Tag Handlers A tag handler for a tag with a body is implemented differently depending on whether the tag handler needs to interact with the body or not By interact we mean that the tag handler reads or modifies the contents of the body Tag Handler Does Not Interact with the Body If the tag handler does not need to interact with the body the tag handler should implement the Tag interface or be derived from TagSupport If the body of the tag needs to be evaluated the doStartTag method needs to return EVAL_BODY_INCLUDE otherwise it should return SKIP_BODY If a tag handler needs to iteratively evaluate the body it should implement the IterationTag interface or be derived from TagSupport It should return EVAL_BODY_AGAIN from the doStartTag and doAfterBody methods if it deter mines th
233. ecification and the SOAP with Attachments specification The complete JAXM API is presented in two packages e javax xml soap the package defined in the SOAP with Attachments API for Java SAAJ 1 1 specification This is the basic package for SOAP messaging which contains the API for creating and populating a SOAP message This package has all the API necessary for sending request response messages Request response messages are explained in SOAPConnection page 296 The current version is SAAJ 1 1_02 e javax xml messaging the package defined in the JAXM 1 1 specifica tion This package contains the API needed for using a messaging provider and thus for being able to send one way messages One way messages ire explained in ProviderConnection page 297 The current version is JAXM 1 1_01 Originally both packages were defined in the JAXM 1 0 specification The javax xml soap package was separated out and expanded into the SAAJ 1 1 specification so that now it has no dependencies on the javax xm1 messaging package and thus can be used independently The SAAJ API also makes it easier to create XML fragments which are especially helpful for developing JAX RPC implementations The javax xml messaging package defined in the JAXM 1 1 specification maintains its dependency on the java xml soap package because the soap package contains the API used for creating and manipulating SOAP messages In other words a client sending requ
234. ed Information Standards Their home site is http www oasis open org The DTD repository they sponsor is at http www XML org one way messaging A method of transmitting messages without having to block until a response is received OS principal A principal native to the operating system on which the Web services plat form is executing ABCDEFGHIJKLMNOPQRSTUVWXYZ parameter entity An entity that consists of DTD specifications as distinct from a general entity A parameter entity defined in the DTD can then be referenced at other points in order to prevent having to recode the definition at each location it is used parsed entity A general entity that contains XML and which is therefore parsed when inserted into the XML document as opposed to an unparsed entity parser A module that reads in XML data from an input source and breaks it up into chunks so that your program knows when it is working with a tag an attribute or element data A nonvalidating parser ensures that the XML data is well formed but does not verify that it is valid See also validating parser principal The identity assigned to a user as a result of authentication privilege A security attribute that does not have the property of uniqueness and that may be shared by many principals processing instruction Information contained in an XML structure that is intended to be interpreted by a specific application 445 programmatic security Security decisi
235. ed in detail in the tutorials for each API In addition to data portability and code portability Web services need to be scal able secure and efficient especially as they grow The Java 2 Platform Enter prise Edition is specifically designed to fill just such needs It facilitates the really hard part of developing Web services which is programming the infra structure or plumbing This infrastructure includes features such as security distributed transaction management and connection pool management all of which are essential for industrial strength Web services And because compo nents are reusable development time is substantially reduced Because XML and the Java platform work so well together they have come to play a central role in Web services In fact the advantages offered by the Java APIs for XML and the J2EE platform make them the ideal combination for deploying Web services The APIs described in this chapter complement and layer on top of the J2EE APIs These APIs enable the Java community developers and tool and container vendors to start developing Web services applications and products using stan dard Java APIs that maintain the fundamental Write Once Run Anywhere proposition of Java technology In the Sun ONE Application Server these APIs are found in the lt S1AS7_HOME gt share 1ib directory and are automatically loaded in the server s OVERVIEW OF THE JAVA APIS FOR XML 241 classpath In the S
236. eed to have the Sun ONE Application Server running in order to use JAXR Mounting the Filesystem Before you can compile the examples you must mount the filesystem To do so 1 Select the Filesystems tab of the Explorer 2 Choose Mount Filesystem from the File menu EDITING THE PROPERTIES FILE 373 3 Mount the following directory lt INSTALL gt j2eetutorial examples jaxr Editing the Properties File Before you compile the examples edit the file JAXRExamples properties as follows 1 Right click the file and choose the Edit menu item 2 Edit the following lines to specify the registry you wish to access For both the queryURL and the publishURL assignments comment out all but the registry you wish to access The default is the Sun ONE Studio internal UDDI Server Registry so if you will be using this registry on your own system you do not need to change this section Uncomment one pair of query and publish URLs IBM query url http uddi ibm com testregistry inquiryapi publish url https uddi ibm com testregistry protect publishapi Microsoft query url http test uddi microsoft com inquire publish url https test uddi microsoft com publish Registry Server query url http localhost 8089 registry server RegistryServerServlet publish url http localhost 8089 registry server RegistryServerServlet If the internal UDDI Server Registry is running on a system other than your own specify t
237. efaults for internal Registry registry username testuser registry password testuser If you will be using a public registry edit the following lines which con tain empty strings for the proxy hosts to specify your own proxy settings The proxy host is the system on your network through which you access the Internet you usually specify it in your Internet browser settings You can leave this value empty to use the internal UDDI Server Registry HTTP and HTTPS proxy host and port ignored by internal Registry http proxyHost http proxyPort 8080 https proxyHost https proxyPort 8080 The proxy ports have the value 8080 which is the usual one change this string if your proxy uses a different port For a public registry your entries usually follow this pattern http proxyHost proxyhost mydomain http proxyPort 8080 https proxyHost proxyhost mydomain https proxyPort 8080 Feel free to change any of the organization data in the remainder of the file This data is used by the publishing examples JAXRPublish and JAXRPub lishPostal STARTING THE INTERNAL UDDI SERVER REGISTRY 6 Save and close the file You can edit the JAXRExamples properties file at any time When you run the client examples they use the latest version of the file Starting the Intemal UDDI Server Registry If you plan to use the internal UDDI Server Registry perform the following steps 1 Select the Runtime tab of the Explorer 2
238. efix c gt This directive references the JSTL core tag library discussed in Chapter 6 When you use an absolute URI you do not have to add the taglib element to web xm1 the JSP container automatically locates the TLD inside the JSTL library imple mentation Making the Tag Library Implementation Available A tag library implementation can be made available to a Web application in two basic ways The classes implementing the tag handlers can be stored in an unpacked form in the WEB INF classes subdirectory of the Web application Alternatively if the library is distributed as a JAR it is stored the WEB INF 1ib directory of the Web application Types of Tags JSP custom tags are written using XML syntax They have a start tag and end tag and possibly a body lt tt tag gt body lt tt tag gt A custom tag with no body is expressed as follows lt tt tag gt Simple Tags A simple tag contains no body and no attributes lt tt simple gt 120 CUSTOM TAGS IN JSP PAGES Tags with Atinbutes A custom tag can have attributes Attributes are listed in the start tag and have the syntax attr value Attribute values serve to customize the behavior of a custom tag just as parameters are used to customize the behavior of a method You specify the types of a tag s attributes in a tag library descriptor see Tags with Attributes page 127 You can set an attribute value from a String constant or a runtime expression
239. elements In this section we con sider only elements For more information on attributes consult the namespace specification at http www w3 org TR REC xm 1 names Defning a Namespace ina DID In a DTD you define a namespace that an element belongs to by adding an attribute to the element s definition where the attribute name is xmlns xml namespace For example you could do that in slideshow dtd by adding an entry like the following in the title element s attribute list definition lt ELEMENT title inline gt lt ATTLIST title xmIns CDATA FIXED http www example com slideshow gt Declaring the attribute as FIXED has several important features e It prevents the document from specifying any non matching value for the xm1ns attribute e The element defined in this DTD is made unique because the parser understands the xmlns attribute so it does not conflict with an element USING NAMESPACES that has the same name in another DTD That allows multiple DTDs to use the same element name without generating a parser error e When a document specifies the xmlns attribute for a tag the document selects the element definition with a matching attribute To be thorough every element name in your DTD would get the exact same attribute with the same value Here though we re only concerned about the title element Note too that you are using a CDATA string to supply the URI In this case we ve speci
240. elopment environment That makes it easy to debug your programs and makes it useful for storing small amounts of data At the other end of the spectrum an XML front end to a database makes it possible to efficiently store large amounts of XML data as well So XML pro vides scalability for anything from small configuration files to a company wide data repository Wuy Is XML IMPORTANT Data Identification XML tells you what kind of data you have not how to display it Because the markup tags identify the information and break up the data into parts an email program can process it a search program can look for messages sent to particu lar people and an address book can extract the address information from the rest of the message In short because the different parts of the information have been identified they can be used in different ways by different applications Styla bility When display is important the stylesheet standard XSL page 191 lets you dictate how to portray the data For example the stylesheet for lt to gt you yourAddress com lt to gt can Say 1 Start a new line 2 Display To in bold followed by a space 3 Display the destination data Which produces To you yourAddress Of course you could have done the same thing in HTML but you wouldn t be able to process the data with search programs and address extraction programs and the like More importantly since XML is inherently style free y
241. elves create a response Instead a filter provides functionality that can be attached to any kind of Web resource As a consequence a filter should not have any dependencies on a Web resource for which it is acting as a filter so that PROGRAMMING FILTERS it can be composable with more than one type of Web resource The main tasks that a filter can perform are as follows e Query the request and act accordingly e Block the request and response pair from passing any further e Modify the request headers and data You do this by providing a custom ized version of the request e Modify the response headers and data You do this by providing a custom ized version of the response e Interact with external resources Applications of filters include authentication logging image conversion data compression encryption tokenizing streams and XML transformations and so on You can configure a Web resource to be filtered by a chain of zero one or more filters in a specific order This chain is specified when the Web application con taining the component is deployed and is instantiated when a Web container loads the component In summary the tasks involved in using filters include e Programming the filter e Programming customized requests and responses e Specifying the filter chain for each Web resource Programming Filters The filtering API is defined by the Filter FilterChain and FilterConfig interfaces in the ja
242. ementation These methods not only create a SOAPHeader object but also give it content You can use these methods because your SOAPMessage object is an EbXMLMessageImp1 object giving you access to the methods defined in EbXMLMessageImp1 message setSender new PartyC http grand products com message setReceiver new PartyC http whiz gizmos com You can view the Javadoc comments for the ebXML and SOAP RP profile implementations provided in Sun ONE Studio at the following location lt S1STUDIO_HOME gt jwsdp docs jaxm profi le com sun xml messaging If you are not using a profile or you want to set content for a header not covered by your profile s implementation you need to follow the steps shown in the next section Adding Content to the Header To add content to the header you need to create a SOAPHeaderElement object As with all new elements it must have an associated Name object which you cre ate using the message s SOAPEnvelope object The following code fragment retrieves the SOAPHeader object from envelope and adds a new SOAPHeaderElement object to it SOAPHeader header envelope getHeader Name headerName envelope createName Purchase Order PO http www sonata com order SOAPHeaderElement headerElement header addHeaderE 1ement headerName At this point header contains the SOAPHeaderElement object headerElement identified by the Name object headerName Note that the addHeaderElement
243. enames 118 listener 123 mapping name to location 118 tag 124 TagExtraInfo 129 taglib 118 tags 177 179 closing 179 empty 179 nesting 179 taxonomies finding with JAXR 363 ISO 3166 357 NAICS 357 377 UNSPSC 357 user defined 366 using to find organizations 358 The Java Message Service Tutori al 11 transactions Web components 58 TREX 193 U UBL 199 UDDI 263 266 327 getting access to public regis tries 351 registries 252 348 UDDI Server Registry 349 starting 375 stopping 382 Unavai lableException 59 Universal Description Discovery and Integration registry See UDDI registry Universal Standard Products and Services Classification See UNSPSC unparsed entity 222 UNSPSC 357 INDEX 473 yV value types 272 version 181 W W3C 193 241 269 286 WAR files 254 JavaBeans components in 28 Web clients 7 maintaining state across re quests 76 web clients 25 configuring 26 internationalizing 38 J2EE Blueprints 39 running 34 updating 35 Web components 9 accessing databases from 57 applets 9 concurrent access to shared re sources 56 development role 16 forwarding to other Web com ponents 74 including other Web resources 72 invoking other Web resources 72 mapping filters to 70 scope objects 55 sharing information 54 transactions 58 types 9 utility classes 9 Web context 75 web components 25 474 INDEX accessing databases from 39 JSP pages See JSP pages 26 servlets See servlets Web conta
244. ented software development methods Since her conversion to technical writing Stephanie has documented object ori ented databases application servers and enterprise application development methods She is a co author of The J2EE Tutorial Designing Enterprise Applications with the Java 2 Platform Enterprise Edition and Object Oriented Software Development The Fusion Method Java API for XML Messaging Introduction to Web Services Maydene Fisher has documented various Java APIs at Sun Microsystems for the last five years She authored two books on the JOBC API JDBC Data base Access with Java A Tutorial and Annotated Reference and JDBC API Tutorial and Reference Second Edition Universal Data Access for the Java 2 Platform Before joining Sun she helped document the object ori ented programming language ScriptX at Kaleida Labs and worked on Wall Street where she wrote developer and user manuals for complex financial 457 458 computer models written in C In previous lives she has been an English teacher a shopkeeper in Mendocino and a financial planner Java API for RPC based XML Dale Green is a staff writer with Sun Microsystems where he documents the J2EE platform and the Java API for RPC based XML In previous positi ns he programmed business applications designed databases taught technical classes and documented RDBMS products He wrote the Internationaliza tion and Reflection trails for the Java Tutorial C
245. enterprise information system The applications that comprise an enterprise s existing system for handling company wide information These applications provide an information infrastructure for an enterprise An enterprise information system offers a well defined set of services to its clients These services are exposed to cli ents as local and or remote interfaces Examples of enterprise information systems include enterprise resource planning systems mainframe transac tion processing systems and legacy database systems enterprise information system resource An entity that provides enterprise information system specific functionality to its clients Examples are a record or set of records in a database system a business object in an enterprise resource planning system and a transaction program in a transaction processing system entity A distinct individual item that can be included in an XML document by ref erencing it Such an entity reference can name an entity as small as a charac ter for example amp It which references the less than symbol or left angle bracket lt An entity reference can also reference an entire document or external entity or a collection of DTD definitions a parameter entity entity bean An enterprise bean that represents persistent data maintained in a database An entity bean can manage its own persistence or can delegate this function to its container An entity bean is identified by a prim
246. ention JSTL follows is to use the name var for any tag attribute that exports information about the tag For example the forEach tag exposes the current item of the shopping cart it is iterating over in the following way lt c forEach var item items sessionScope cart items gt lt c forEach gt The name var was selected to highlight the fact that the scoped variable exposed is not a scripting variable which is normally the case for attributes named id In situations where a tag exposes more than one piece of information the name var is used for the primary piece of information being exported and an appro priate name is selected for any other secondary piece of information exposed For example iteration status information is exported by the forEach tag via the attribute status CORE TAGS 159 Core Tags The core tags include those related to expressions flow control and a generic way to access URL based resources whose content can then be included or pro cessed within the JSP page Table 6 3 Core Tags Function Tags catch out remove set Expression Language Support choose when otherwise forEach forTokens if Flow Control import param redirect param url param URL Management Expression Tags The out tag evaluates an expression and outputs the result of the evaluation to the current JspWriter object It is the equivalent of the JSP syntax lt expression gt For example show
247. ents are contained in the cbservice package which is found in the directory lt INSTALL gt j2eetutorial examples cb WEB INF classes cbser vice JAX RPC CLIENT J AX RPC Client The JAX RPC client is generated directly from the Web service and is located in lt INSTALL gt j2eetutorial examples cb jaxrpc clientutil Since the JAX RPC client returns JavaBeans components defined in the clientutil package under the jaxrpc directory and the Coffee Break server class that accesses those components see CheckoutFormBean page 412 uses types defined in the cbservice package CheckoutFormBean converts clientutil types to equiva lent types defined in the cbservice package J AXM Client The Coffee Break server sends requests to its JAXM distributor Because the request response form of JAXM messaging is being used the client applications use the SOAPConnection method call to send messages SOAPMessage response con call request endpoint Accordingly the client code has two major tasks The first is to create and send the request the second is to extract the content from the response These tasks are handled by the classes lt INSTALL gt j2eetutorial examples cb WEB INF classes cbservice JAXMPriceListRequest and lt INSTALL gt j2eetutorial examples cb WEB INF classes cbservice JAX MOrderRequest Sending the Request This section covers the code for creating and sending the request for an updated price list This is done in the getPr
248. envelope msg getSOAPPart getEnvelope THE SOAPFAULTTEST EXAMPLE 337 SOAPBody body envelope getBody SOAPFault fault body addFaultQ fault setFaultCodeC Client fault setFaultString Message does not have necessary info fault setFaultActor http gizmos com order Detail detail fault addDetailQ Name entryName envelope createName order PO http gizmos com orders DetailEntry entry detail addDetailEntry CentryName entry addTextNode quantity element does not have a value Name entryName2 envelope createName confirmation PO http gizmos com confirm DetailEntry entry2 detail addDetailEntry CentryName2 entry2 addTextNode Incomplete address no zip code msg saveChanges Now retrieve the SOAPFault object and its contents after checking to see that there is one System out printIn Here is what the XML message looks like msg writeTo System out System out printInQd System out printInQ if body hasFaultQ fault body getFaultQ String code fault getFaultCode String string fault getFaultStringQ String actor fault getFaultActor System out printInC SOAP fault contains System out printiInC fault code code System out printInC fault string string if C actor null System out printIn fault actor 338 WEB SERVICES MESSAGING WITH JAXM actor detail
249. er The con tainer can be a standalone Web container or part of a J2EE server OVERVIEW OF JAX RPC A Web service can make itself available to potential clients by describing itself in a Web Services Description Language WSDL document A WSDL descrip tion is an XML document that gives all the pertinent information about a Web service including its name the operations that can be called on it the parameters for those operations and the location of where to send requests A consumer Web client can use the WSDL document to discover what the service offers and how to access it How a developer can use a WSDL document in the creation of a Web service is discussed later Interoperability Perhaps the most important requirement for a Web service is that it be interoper able across clients and servers With JAX RPC a client written in a language other than the Java programming language can access a Web service developed and deployed on the Java platform Conversely a client written in the Java pro gramming language can communicate with a service that was developed and deployed using some other platform What makes this interoperability possible is JAX RPC s support for SOAP and WSDL SOAP defines standards for XML messaging and the mapping of data types so that applications adhering to these standards can communicate with each other JAX RPC adheres to SOAP standards and is in fact based on SOAP messaging That is a JAX RPC remote pro
250. er and that the actor at http gizmos com orders is having the problem If the message were being routed only to its ultimate destination there would have been no need for setting a fault actor Also note that fault does not have a Detail object because it does not relate to the SOAPBody object The following code fragment creates a SOAPFau1t object that includes a Detail object Note that a SOAPFau1t object may have only one Detail object which is simply a container for DetailEntry objects but the Detail object may have multiple DetailEntry objects The Detail object in the following lines of code has two DetailEntry objects added to it SOAPFault fault body addFaultQ fault setFaultCodeC Client fault setFaultStringC Message does not have necessary info Detail detail fault addDetailQ 321 322 WEB SERVICES MESSAGING WITH JAXM Name entryName envelope createName order PO http gizmos com orders DetailEntry entry detail addDetailEntry CentryName entry addTextNode quantity element does not have a value Name entryName2 envelope createName confirmation PO http gizmos com confirm DetailEntry entry2 detail addDetailEntry CentryName2 entry2 addTextNode Incomplete address no zip code Retrieving Fault Information Just as the SOAPFau1t interface provides convenience methods for adding infor mation it also provides convenience methods for retrieving that information T
251. er in ways previously unimaginable For more information on the background and motivation of XML see this great article in Scientific American at http www sciam com 1999 0599issue 0599bosak html XML and Related Specs Digesting the Alphabet Soup Now that you have a basic understanding of XML it makes sense to get a high level overview of the various XML related acronyms and what they mean There is a lot of work going on around XML so there is a lot to learn The current APIs for accessing XML documents either serially or in random access mode are respectively SAX page 189 and DOM page 189 The speci fications for ensuring the validity of XML documents are DTD page 190 the 188 UNDERSTANDING XML original mechanism defined as part of the XML specification and various Schema Standards page 192 proposals newer mechanisms that use XML syn tax to do the job of describing validation criteria Other future standards that are nearing completion include the XSL page 191 standard a mechanism for setting up translations of XML documents for example to HTML or other XML and for dictating how the document is ren dered The transformation part of that standard XSLT XPATH page 191 is completed and covered in this tutorial Another effort nearing completion is the XML Link Language specification XML Linking page 194 which enables links between XML documents Those are the major initiatives you will want to
252. er text is or is not allowed between elements in the structure In the sample file you have been working with the slideshow element is an example of a data element it contains only subelements with no intervening text The item element on the other hand might be termed a document element because it is defined to include both text and subelements As you work through this tutorial you will see how to expand the definition of the title element to include HTML style markup which will turn it into a docu ment element as well Defning Atinbutes and Entities in the DID The DTD you ve defined so far is fine for use with the nonvalidating parser It tells where text is expected and where it isn t which is all the nonvalidating parser is going to pay attention to But for use with the validating parser the DTD needs to specify the valid attributes for the different elements You ll do that in this section after which you ll define one internal entity and one external entity that you can reference in your XML file Defining Atinbutes in the DID Let s start by defining the attributes for the elements in the slide presentation Note The XML written in this section is contained in slideshowlb dtd The browsable version is s1ideshow1b dtd htm1 Add the text highlighted below to define the attributes for the slideshow ele ment lt ELEMENT slideshow slide gt lt ATTLIST slideshow title CDATA REQUIRED date CDATA
253. er will typically create a thread to handle each request If you want to ensure that a servlet instance handles only one request at a time a servlet can implement the SingleThreadMode1l interface If a servlet implements this interface you are guaranteed that no two threads will exe cute concurrently in the servlet s service method A Web container can ACCESSING DATABASES implement this guarantee by synchronizing access to a single instance of the servlet or by maintaining a pool of Web component instances and dis patching each new request to a free instance Note This interface does not prevent synchronization problems that result from Web components accessing shared resources such as static class variables or exter nal objects When resources can be accessed concurrently they can be used in an inconsis tent fashion To prevent this you must control the access using the synchroniza tion techniques described in the Threads lesson in The Java Tutorial In the previous section we showed five scoped attributes shared by more than one servlet bookDB cart currency hitCounter and orderCounter The bookDB attribute is discussed in the next section The cart currency and counters can be set and read by multiple multithreaded servlets To prevent these objects from being used inconsistently access is controlled by synchronized methods For example here is the uti1 Counter class public class Counter private int counter publ
254. erarchical data structures Once again as with HTML whitespace is essentially irrelevant so you can for mat the data for readability and yet still process it easily with a program Unlike HTML however in XML you could easily search a data set for messages con WHAT Is XML 179 taining cool in the subject because the XML tags identify the content of the data rather than specifying its representation Tags and Atinbutes Tags can also contain attributes additional information included as part of the tag itself within the tag s angle brackets The following example shows an email message structure that uses attributes for the to from and subject fields lt message to you yourAddress com from me myAddress com subject XML Is Really Cool gt lt text gt How many ways is XML cool Let me count the ways lt text gt lt message gt As in HTML the attribute name is followed by an equal sign and the attribute value and multiple attributes are separated by spaces Unlike HTML however in XML commas between attributes are not ignored if present they generate an error Since you could design a data structure like lt message gt equally well using either attributes or tags it can take a considerable amount of thought to figure out which design is best for your purposes Designing an XML Data Structure page 233 includes ideas to help you decide when to use attributes and when to use tags
255. ere is the declaration from the Duke s Bookstore descriptor lt context param gt lt param name gt javax servlet jsp jstl fmt 1localizationContext lt param name gt lt param value gt messages BookstoreMessages lt param value gt lt context param gt message Tag The message tag is used to output localized strings The following tag from cat alog jsp lt h3 gt lt fmt message key Choose gt lt h3 gt is used to output a string inviting customers to choose a book from the catalog The param subtag provides a single argument for parametric replacement to the compound message or pattern in its parent message tag One param tag must be specified for each variable in the compound message or pattern Parametric replacement takes place in the order of the param tags Formatting Tags JSTL provides a set of tags for parsing and formatting locale sensitive numbers and dates The formatNumber tag is used to output localized numbers The following tag from showcart jsp lt fmt formatNumber value book price type Ccurrency gt is used to display a localized price for a book Note that since the price is main tained in the database in dollars the localization is somewhat simplistic because the formatNumber tag is unaware of exchange rates The tag formats currencies but does not convert them Analogous tags for formatting dates formatDate and parsing numbers and dates parseNumber parseDate are also availabl
256. ers defined immediately after doPost to read and write the headers in req It then gets the content of req as a stream and passes the headers and the input stream to the method MessageFactory createMessage The result is that the SOAPMessage object msg contains the request for a price list Note that in this case msg does not have any headers because the message sent in PriceListRe quest did not have any headers public void doPost HttpServletRequest req HttpServletResponse resp throws ServletException IOException try Get all the headers from the HTTP request MimeHeaders headers getHeaders req Get the body of the HTTP request InputStream is req getInputStreamQ Now internalize the contents of the HTTP request and create a SOAPMessage SOAPMessage msg msgFactory createMessage headers is Next the code declares the SOAPMessage object reply and populates it by call ing the method onMessage SOAPMessage reply null reply onMessage msg If reply has anything in it its contents are saved the status of resp is set to OK and the headers and content of reply are written to resp If reply is empty the status of resp is set to indicate that there is no content if reply null Need to call saveChanges because we re going to use the MimeHeaders to set HTTP response information These MimeHeaders are generated as part of the save JAXM SERVICE if Creply saveRequiredQ reply s
257. ers HitCounterFilter and filters OrderFilter and they are mapped to BookStoreServlet and ReceiptServlet respectively 6 Browse the listener property a Click the Listeners property and open the property editor b Notice that the listener class is 1isteners ContextListener 7 Browse the servlet definitions and their mappings a Click the Servlets property and open the property editor b Notice that there are 7 servlets listed defined and mapped to URLs 8 Browse the resource references a Select the Resources Property sheet a Click the Resource References property and open the property editor b Note the resource reference named jdbc BookDB Troubleshooting Because we have specified an error page you will see the message The appli cation is unavailable Please try later when an exception occurs You will have to look in the application server s log to determine the cause of the exception The log file is lt S1AS7_HOME gt domains domainl server1 logs server log You can view the log in the application server administration tool as follows 1 Start the administration console by opening the URL http local host 4848 in a browser 2 Select the server1 node 3 Select the Logging tab 4 Click the View Event Log link Here are the exceptions that can be returned and their causes e UnavailableException Returned if a servlet can t retrieve the Web context attribute representing the bookstore database This w
258. erver1 node 3 Expand the nodes Applications Web Apps To list the Web applications deployed on a server with the IDE 1 Select the Runtime tab in the Explorer 2 Expand the nodes Server Registry Installed Servers Sun ONE Applica tion Server 7 localhost 4848 serverl Deployed Web Modules Running Web Applications A Web application is executed when a Web browser references a URL that is mapped to component Once you have installed or deployed the He1101 applica tion you can run the Web application by pointing a browser at http lt host gt 80 hellol greeting UPDATING WEB MODULES Replace lt host gt with the name of the host running the application server If your browser is running on the same host as the application server you may replace lt host gt with localhost Updating Web Modules During development you will often need to make changes to Web applications The process for viewing those changes is to 1 Recompile the servlet class 2 Redeploy the application in the server 3 Reload the URL in the client To try this feature modify the servlet version of the Hello application For exam ple you could change the greeting returned by GreetingServlet to be lt h2 gt Hi my name is Duke What s yours lt h2 gt To update the file 1 Edit the file lt INSTALL gt j2eetutorial examples web hel1o01 WEB INF classes GreetingServlet java 2 Redeploy the Web module 3 Reload the URL in the b
259. es http forte sun com ffj documentation si1s41 websrvcs pdf e StockApp Example http wwws sun com software sundev jde examples index htm 288 BUILDING WEB SERVICES WITH JAX RPC 10 Web Services Messaging with J AXM Maydene Fisher and Kim Haase Tue Java API for XML Messaging JAXM makes it possible for developers to do XML messaging using the Java platform By simply making method calls using the JAXM API you can create and send XML messages over the Internet This chapter will help you learn how to use the JAXM API In addition to stepping you through how to use the JAXM API this chapter gives instructions for running the sample JAXM applications included with this tuto rial as a way to help you get started You may prefer to go through both the over view and tutorial before running the samples to make it easier to understand what the sample applications are doing or you may prefer to explore the samples first The overview gives some of the conceptual background behind the JAXM API to help you understand why certain things are done the way they are The tutorial shows you how to use the basic JAXM API giving examples and expla nations of the more commonly used features Finally the code examples in the last part of the tutorial show how to build an application 289 290 WEB SERVICES MESSAGING WITH JAXM The Structure of the J AXM API The JAXM API conforms to the Simple Object Access Protocol SOAP 1 1 sp
260. es get and set methods for the headers Content Type Content Id and Content Location These headers can be helpful in accessing a particular attachment when a message has multiple attachments For example to access the attachments that have particular headers you call the SOAPMessage method getAttachments and pass it the header or headers you are interested in The following code fragment shows one of the ways to use the method setCon tent The Java Object being added is a String which is plain text so the sec ond argument has to be text plain The code also sets a content identifier which can be used to identify this AttachmentPart object After you have added ADDING ATTACHMENTS content to attachment you need to add attachment to the SOAPMessage object which is done in the last line String stringContent Update address for Sunny Skies Inc to 10 Upbeat Street Pleasant Grove CA 95439 attachment setContent stringContent text plain attachment setContentId update_address message addAttachmentPart attachment The variable attachment now represents an AttachmentPart object that con tains the String stringContent and has a header that contains the String text plain It also has a Content Id header with update_address as its value And now attachment is part of message Let s say you also want to attach a JPEG image showing how beautiful the new location is In this case the second argume
261. esponse paradigm servlet container A container that provides the network services over which requests and responses are sent decodes requests and formats responses All servlet con tainers must support HTTP as a protocol for requests and responses but may also support additional request response protocols such as HTTPS servlet container distributed A servlet container that can run a Web application that is tagged as distribut able and that executes across multiple Java virtual machines running on the same host or on different hosts servlet context An object that contains a servlet s view of the Web application within which the servlet is running Using the context a servlet can log events obtain URL references to resources and set and store attributes that other servlets in the context can use servlet mapping Defines an association between a URL pattern and a servlet The mapping is used to map requests to servlets session An object used by a servlet to track a user s interaction with a Web applica tion across multiple HTTP requests session bean An enterprise bean that is created by a client and that usually exists only for the duration of a single client server session A session bean performs opera tions such as calculations or accessing a database for the client Although a session bean may be transactional it is not recoverable should a system crash occur Session bean objects can be either stateless or can ma
262. est response messages can use just the javax xm1 soap API A Web service or client that uses one way messaging will need to use API from both the javax xml soap and javax xml messaging packages Note In this document JAXM 1 1_01 API refers to the API in the javax xml messaging package SAAJ API refers to the API in the javax xml1 soap package JAXM API is a more generic term referring to all of the API used for SOAP messaging that is the API in both packages OVERVIEW OF JAXM 291 In addition to stepping you through how to use the JAXM API this chapter gives instructions for running the sample JAXM applications included with this tuto rial as a way to help you get started You may prefer to go through both the over view and tutorial before running the samples to make it easier to understand what the sample applications are doing or you may prefer to explore the samples first The overview gives some of the conceptual background behind the JAXM API to help you understand why certain things are done the way they are The tutorial shows you how to use the basic JAXM API giving examples and expla nations of the more commonly used features Finally the code examples in the last part of the tutorial show how to build an application Overview of J AXM This overview presents a high level view of how JAXM messaging works and explains concepts in general terms Its goal is to give you some terminology and a framework for t
263. etProperty name book property title gt lt h2 gt Finally the iterator tag described in detail later in the chapter sets a scripting variable name to each member of a collection lt tlt iterator name member type org Member group lt dept getMembers gt gt Cooperating Tags Custom tags can cooperate with each other through shared objects 121 122 CUSTOM TAGS IN JSP PAGES In the following example tag1 creates an object called obj1 which is then reused by tag2 lt tt tagl attrl obj1 valuel value gt lt tt itag2 attrl obj1l gt In the next example an object created by the enclosing tag of a group of nested tags is available to all inner tags Since the object is not named the potential for naming conflicts is reduced This example illustrates how a set of cooperating nested tags would appear in a JSP page lt tt outerTag gt lt tt innerTag gt lt tt outerTag gt The Duke s Bookstore page template jsp uses a set of cooperating tags to define the screens of the application These tags are described in A Template Tag Library page 141 Defining Tags To define a tag you need to e Declare the tag in a tag library descriptor e Develop a tag handler and helper classes for the tag This section describes the properties of TLDs and tag handlers and explains how to develop library descriptor elements and tag handlers for each type of tag intro duced in the previous section Tag Li
264. ethod and retrieved with the getValue method The following example illustrates a tag handler that supports both the named and private object approaches to sharing objects In the example the handler for a query tag checks whether an attribute named connection has been set in the doStartTag method If the connection attribute has been set the handler retrieves the connection object from the page context Otherwise the tag handler first retrieves the tag handler for the enclosing tag and then retrieves the connec tion object from that handler public class QueryTag extends BodyTagSupport private String connectionId public int doStartTag throws JspException String cid getConnectionQ if cid null there is a connection id use it connection Connection pageContext getAttribute cid else ConnectionTag ancestorTag CConnectionTag findAncestorwithClass this ConnectionTag class if CancestorTag null throw new JspTagException A query without a connection attribute must be nested within a connection tag connection ancestorTag getConnection EXAMPLES 137 The query tag implemented by this tag handler could be used in either of the fol lowing ways lt tt connection id con 1 gt lt tt connection gt lt tt query id balances connection con01 gt SELECT account balance FROM acct_table where customer_number lt request getCustno gt lt tt query gt lt tt
265. etween a client and a Web container should be pro tected The protection can be the prevention of tampering with the data or prevention of eavesdropping on the data ABCDEFGHIJKLMNOPQRSTUVWXYZ valid A valid XML document in addition to being well formed conforms to all the constraints imposed by a DTD It does not contain any tags that are not 452 permitted by the DTD and the order of the tags conforms to the DTD s spec ifications validating parser A parser that ensures that an XML document is valid as well as well formed See also parser virtual host Multiple hosts domain names mapped to a single IP ABCDEFGHIJKLMNOPOQRSTUVWXYZ W3C World Wide Web Consortium The international body that governs Internet standards WAR file Web application archive A JAR archive that contains a Web module warning A SAX parser warning is generated when the document s DTD contains duplicate definitions and similar situations that are not necessarily an error but which the document author might like to know about since they could be See also fatal error error Web application An application written for the Internet including those built with Java tech nologies such as JavaServer Pages and servlets as well as those built with non Java technologies such as CGI and Perl Web Application Archive WAR A hierarchy of directories and files in a standard Web application format contained in a packed file with an extension
266. exposed as XML based Web services using JAX RPC and J2EE component models Java Authentication and Authonzation Service The Java Authentication and Authorization Service JAAS provides a way for a J2EE application to authenticate and authorize a specific user or group of users to run it JAAS is a Java programing language version of the standard Pluggable Authenti cation Module PAM framework that extends the Java 2 Platform security archi tecture to support user based authorization SIMPLIFIED SYSTEMS INTEGRATION 23 Simplified Systems Integration The J2EE platform is a platform independent full systems integration solution that creates an open marketplace in which every vendor can sell to every cus tomer Such a marketplace encourages vendors to compete not by trying to lock customers into their technologies but by trying to outdo each other by providing products and services that benefit customers such as better performance better tools or better customer support The J2EE APIs enable systems and applications integration through the follow ing e Unified application model across tiers with enterprise beans e Simplified response and request mechanism with JSP pages and servlets e Reliable security model with JAAS e XML based data interchange integration with JAXP e Simplified interoperability with the J2EE Connector Architecture e Easy database connectivity with the JDBC API e Enterprise application integration
267. f you re new to the Java API for XML based RPC JAX RPC this chapter is the place to start The chapter starts by listing the supported types and then shows you how to build a simple Web service and three types of clients Types Supported By J AX RPC Behind the scenes JAX RPC maps types of the Java programming language to XML WSDL definitions For example JAX RPC maps the java lang String class to the xsd string XML data type Application developers don t need to know the details of these mappings but they should be aware that not every class in the Java 2 Standard Edition J2SE can be used as a method parameter or return type in JAX RPC J 2SE SDK Classes JAX RPC supports the following J2SE SDK classes java lang Boolean java lang Byte java lang Double java lang Float java lang Integer java lang Long java lang Short java lang String java math BigDecimal java math BigInteger java util Calendar java util Date PRIMITIVES 271 This release of JAX RPC also supports several implementation classes of the java util Collection interface See Table 9 1 Table 9 1 Supported Classes of the Java Collections Framework java util Collection Interface Implementation Classes ArrayList LinkedList Stack Vector HashMap Hashtable Properties TreeMap HashSet TreeSet Primitives JAX RPC supports the following primitive types of the Java programming lan guage boolean byte double float int long
268. fault is an error related to the SOAPBody object If for example the fault code is Client indicating that the message could not be processed because of a problem in the SOAPBody object the SOAPFault object must contain a Detail object that gives details about the problem If a SOAPFault object does not contain a Detail object it can be assumed that the SOAPBody object was processed successfully SOAP FAULTS Creating and Populating a SOAPFault Object You have already seen how to add content to a SOAPBody object this section will walk you through adding a SOAPFau1t object to a SOAPBody object and then add ing its constituent parts As with adding content the first step is to access the SOAPBody object SOAPEnvelope envelope msg getSOAPPart getEnvelope SOAPBody body envelope getBody With the SOAPBody object body in hand you can use it to create a SOAPFault object with the following line of code SOAPFault fault body addFaultQ The following code uses convenience methods to add elements and their values to the SOAPFau1t object fault For example the method setFaultCode creates an element adds it to fault and adds a Text node with the value Server fault setFaultCodeC Server fault setFaultActor http gizmos com orders fault setFaultStringC Server not responding The SOAPFau1t object fault created in the previous lines of code indicates that the cause of the problem is an unavailable serv
269. fee line It will need to publish a price list order form in HTML for its Web site But before that can be done the company needs to determine what prices it will charge The engineer writes an application that will multiply each wholesale price by 135 to arrive at the price that The Coffee Break will charge With a few modifica tions the list of retail prices will become the online order form The engineer uses JavaServer Pages JSP technology to create an HTML order form that customers can use to order coffee online From the JSP page she gets the name and price of each coffee and then she inserts them into an HTML table on the JSP page The customer enters the quantity of each coffee desired and clicks the Submit button to send the order Conclusion Although this scenario is simplified for the sake of brevity it illustrates how XML technologies can be used in the world of Web services With the availabil ity of the Java APIs for XML and the J2EE platform creating Web services and writing applications that use them have both gotten easier 267 268 INTRODUCTION TO WEB SERVICES Chapter 12 demonstrates a simple implementation of this scenario 9 Building Web Services With J AX RPC Dale Green J AX RPC stands for Java API for XML based RPC It s an API for building Web services and clients that use remote procedure calls RPC and XML Often used in a distributed client server model an RPC mechanism enables cl
270. ficationSchemes schemes The BulkResponse object returned by the saveClassificationSchemes method contains the key for the classification scheme which you need to retrieve if br getStatus JAXRResponse STATUS_SUCCESS System out printInC Saved ClassificationScheme Collection schemeKeys br getCollection Iterator keysIter schemeKeys iterator while keysIter hasNextQ javax xml registry infomodel Key key javax xml registry infomodel Key keysIter nextQ System out printInC The postalScheme key is key getIdQ System out printInC Use this key as the scheme uuid in the taxonomy file 2 In an XML file define a taxonomy structure that is compliant with the JAXR Predefined Concepts DTD Enter the ClassificationScheme ele ment in your taxonomy XML file by specifying the returned key ID value as the id attribute and the name as the name attribute For the code frag ment above for example the opening tag for the JAXRClassification Scheme element looks something like this all on one line lt JAXRClassi ficationScheme id uuid nnnnannnn nnnn nnnn nnnn nnnannnnnnnnn name MyScheme gt The ClassificationScheme id must be a UUID 3 Enter each JAXRConcept element in your taxonomy XML file by specify ing the following four attributes in this order a id is the JAXRClassificationScheme id value followed by a sepa rator followed by the code of the JAXRConcept element USING
271. fied an URL But you could also specify a URN possi bly by specifying a prefix like urn instead of http URNs are currently being researched They re not seeing a lot of action at the moment but that could change in the future Referencing a Namespace When a document uses an element name that exists in only one of the DTDs or schemas it references the name does not need to be qualified But when an ele ment name that has multiple definitions is used some sort of qualification is a necessity Note In point of fact an element name is always qualified by it s default namespace as defined by name of the DTD file it resides in As long as there as is only one definition for the name the qualification is implicit You qualify a reference to an element name by specifying the xm1ns attribute as shown here lt title xmlns http www example com slideshow gt Overview lt title gt The specified namespace applies to that element and to any elements contained within it Defining a Namespace Prefix When you only need one namespace reference it s not such a big deal But when you need to make the same reference several times adding xmlns attributes becomes unwieldy It also makes it harder to change the name of the namespace at a later date 231 232 UNDERSTANDING XML The alternative is to define a namespace prefix which as simple as specifying xmulns a colon and the prefix name before the attribute valu
272. first access the SOAPBody object using the mes sage to get the envelope and the envelope to get the body Then you access its SOAPBodyE lement object because that is the element to which content was added in the example In a later section you will see how to add content directly to the SOAPBody object in which case you would not need to access the SOAPBodyE1e ment object for adding content or for retrieving it To get the content which was added with the method SOAPElement addTextNode you call the method Node getValue Note that getValue returns the value of the immediate child of the element that calls the method Therefore in the following code fragment the CLIENT WITH A MESSAGING PROVIDER 309 method getValue is called on bodyElement the element on which the method addTextNode was called In order to access bodyElement you need to call the method getChildElement on body Passing bodyName to getChildElement returns a java util Itera tor object that contains all of the child elements identified by the Name object bodyName You already know that there is only one so just calling the method next on it will return the SOAPBodyElement you want Note that the method Iterator next returns a Java Object so it is necessary to cast the Object it returns to a SOAPBodyElement object before assigning it to the variable bodyElement SOAPPart sp response getSOAPPartQ SOAPEnvelope env sp getEnvelope SOAPBody sb env getBody
273. g a taglib directive in the page before any custom tag is used lt taglib uri WEB INF template tld prefix tt gt The uri attribute refers to a URI that uniquely identifies the tag library descrip tor TLD described in Tag Library Descriptors page 122 This URI can be direct or indirect The prefix attribute defines the prefix that distinguishes tags defined by a given tag library from those provided by other tag libraries Tag library descriptor file names must have the extension t1d TLD files are stored in the WEB INF directory of the WAR or in a subdirectory of WEB INF You can reference a TLD directly and indirectly The following taglib directive directly references a TLD filename lt taglib uri WEB INF template tld prefix tt gt You can also directory reference a TLD by referencing the library in which the TLD is contained lt taglib uri WEB INF lib template jar prefix tt gt This taglib directive uses a short logical name to indirectly reference the TLD lt taglib uri template prefix tt gt You map a logical name to an absolute location in the Web application deploy ment descriptor To map the logical name template to the absolute location WEB INF template t1d you add a tag library element to web xm1 MAKING THE TAG LIBRARY IMPLEMENTATION AVAILABLE 119 You can also reference a TLD in a tag1ib directive with an absolute URI lt taglib uri http java sun com jstl core pr
274. g point as in Java e String with single and double quotes is escaped as and is escaped as e Null null is escaped as Operators The EL provides the following operators e Arithmetic and div and mod e Logical and amp amp or not e Relational eq ne lt 1t gt gt lt ge gt le Comparisons may be made against other values or against boolean string integer or floating point literals e Empty The empty operator is a prefix operation that can be used to deter mine if a value is nul or empty Consult the JSTL 1 0 Specification for the precedence and effects of these opera tors 158 JAVASERVER PAGES STANDARD TAG LIBRARY Tag Collaboration Tags usually collaborate with their environment in implicit and explicit ways Implicit collaboration is done via a well defined interface that allows nested tags to work seamlessly with the ancestor tag exposing that interface The JSTL itera tor tags support this mode of collaboration Explicit collaboration happens when a tag exposes information to its environ ment Traditionally this has been done by exposing a scripting variable with a JSP scoped attribute providing the actual object Because JSTL has an expres sion language there is less need for scripting variables So the JSTL tags both the EL and RT versions expose information only as JSP scoped attributes no scripting variables are used The conv
275. g the ben efits of another level of componentization to JSP pages 112 JAVASERVER PAGES TECHNOLOGY For example recall the scriptlet used to loop through and display the contents of the Duke s Bookstore shopping cart lt Iterator i cart getItems iteratorQ while i hasNextQ ShoppingCartItem item CShoppingCartItem i nextQ lt tr gt lt td align right bgcolor fffFFF gt lt i tem getQuantityQ gt lt td gt An iterate custom tag eliminates the code logic and manages the scripting variable item that references elements in the shopping cart lt logic iterate id item collection lt cart getItems gt gt lt tr gt lt td align right bgcolor ffffff gt lt i tem getQuantity gt lt td gt lt logic iterate gt Custom tags are packaged and distributed in a unit called a tag library The syn tax of custom tags is the same as that used for the JSP elements namely lt pre fix tag gt for custom tags however prefix is defined by the user of the tag library and tag is defined by the tag developer Custom Tags in JSP Pages page 113 explains how to use and develop custom tags Further Information For further information on JavaServer Pages technology see e Resources listed on the Web site http java sun com products jsp e The JavaServer Pages 1 2 Specification 5 Custom Tags in J SP Pages Stephanie Bodoff Tue standard JSP tags for invoking operations o
276. geFactory creates including m in the previous line of code will be basic SOAP messages This means that they will have no pre defined headers Part of the flexibility of the JAXM API is that it allows a specific usage of a SOAP header For example protocols such as ebXML can be built on top of SOAP messaging to provide the implementation of additional headers thus enabling additional functionality This usage of SOAP by a given standards group or industry is called a profile See the JAXM tutorial section Profiles page 299 for more information on profiles 259 260 INTRODUCTION TO WEB SERVICES In the second way to create a MessageFactory object you use the Provider Connection method createMessageFactory and give it a profile The SOAP Message objects produced by the resulting MessageFactory object will support the specified profile For example in the following code fragment in which schemaURI is the URI of the schema for the desired profile m2 will support the messaging profile that is supplied to createMessageFactory MessageFactory messageFactory2 con createMessageFactory lt schemaURI gt SOAPMessage m2 messageFactory2 createMessage Each of the new SOAPMessage objects m and m2 automatically contains the required elements SOAPPart SOAPEnvelope and SOAPBody plus the optional element SOAPHeader which is included for convenience The SOAPHeader and SOAPBody objects are initially empty and the following section
277. generic 1 0 findBusiness addAttribute envelope createName maxRows 100 SOAPElement businessName findBusiness addChi ldElement envelope createName name businessName addTextNode args 1 The next line of code creates the Java Object that represents the destination for this message It gets the value of the property named URL from the system property file Object endpoint new URLEndpoint System getProperties getProperty C URL The following line of code saves the changes that have been made to the mes sage This method will be called automatically when the message is sent but it does not hurt to call it explicitly msg saveChanges Next the message msg is sent to the destination that endpoint represents which is the test UDDI registry The method ca11 will block until it gets a SOAPMes sage object back at which point it returns the reply SOAPMessage reply connection call msg endpoint In the next two lines the first prints out a line giving the URL of the sender the test registry and the second prints out the returned message as an XML docu ment System out printInC Received reply from endpoint reply writeTo System out THE UDDIPING EXAMPLE The remaining code makes the reply more user friendly It gets the content from certain elements rather than printing out the whole XML document as it was sent over the wire Because the content is in the SOAPBody object the first
278. ght otherwise have naming conflicts Java API for XML Registries JAXR An API for accessing different kinds of XML registries Java API for XML based RPC JAX RPC An API for building Web services and clients that use remote procedure calls RPC and XML Java Naming and Directory Interface JNDD An API that provides naming and directory functionality Java Secure Socket Extension JSSE A set of packages that enable secure Internet communications Java Transaction API JTA An API that allows applications to access transactions Java Web Services Developer Pack Java WSDP An environment containing key technologies to simplify building of Web services using the Java 2 Platform JavaBeans component A Java class that can be manipulated in a visual builder tool and composed into applications A JavaBeans component must adhere to certain property and event interface conventions JavaMail An API for sending and receiving email JavaServer Pages JSP An extensible Web technology that uses template data custom elements scripting languages and server side Java objects to return dynamic content to a client Typically the template data is HTML or XML elements and in many cases the client is a Web browser JavaServer Pages Standard Tag Library JSTL A tag library that encapsulates core functionality common to many JSP applications JSTL has support for common structural tasks such as iteration and conditio
279. gnored That is the reason that the copyright message appears to start on the next line after the lt item gt element instead of on the same line the first character echoed is actually the newline that follows the comment Summarizing Entities An entity that is referenced in the document content whether internal or exter nal is termed a general entity An entity that contains DTD specifications that are referenced from within the DTD is termed a parameter entity More on that later An entity which contains XML text and markup and which is therefore parsed is known as a parsed entity An entity which contains binary data like images is known as an unparsed entity By its very nature it must be external We ll be discussing references to unparsed entities in the next section of this tutorial REFERENCING BINARY ENTITIES Referencing Binary Entities This section discusses the options for referencing binary files like image files and multimedia data files Using a MIME Data Type There are two ways to go about referencing an unparsed entity like a binary image file One is to use the DTD s NOTATION specification mechanism How ever that mechanism is a complex non intuitive holdover that mostly exists for compatibility with SGML documents We will have occasion to discuss it in a bit more depth when we look at the DTDHandler API but suffice it for now to say that the combination of the recently defined XML namespaces
280. gram development time rather than at execution time as with a JDBC driver standalone client A client that does not use a messaging provider and does not run in a con tainer ABCDEFGHIJKLMNOPQRSTUVWXYZ tag A piece of text that describes a unit of data or element in XML The tag is distinguishable as markup as opposed to data because it is surrounded by angle brackets lt and gt To treat such markup syntax as data you use an entity reference or a CDATA section template A set of formatting instructions that apply to the nodes selected by an XPATH expression 450 transaction An atomic unit of work that modifies data A transaction encloses one or more program statements all of which either complete or roll back Transac tions enable multiple users to access the same data concurrently transaction isolation level The degree to which the intermediate state of the data being modified by a transaction is visible to other concurrent transactions and data being modi fied by other transactions is visible to it transaction manager Provides the services and management functions required to support transac tion demarcation transactional resource management synchronization and transaction context propagation translet Pre compiled version of a transformation ABCDEFGHIJKLMNOPQRSTUVWXYZ Unicode A standard defined by the Unicode Consortium that uses a 16 bit code page which maps digits to characters in languages aroun
281. gt some_text lt b gt lt i gt The Finished Product Here is the completed version of the XML file lt xml version 1 encoding utf 8 gt lt A SAMPLE set of slides gt lt slideshow title Sample Slide Show date Date of publication author Yours Truly gt lt TITLE SLIDE gt lt slide type all1 gt lt title gt Wake up to WonderWidgets lt title gt lt slide gt lt OVERVIEW gt lt slide type all1 gt lt title gt Overview lt title gt lt item gt Why lt em gt WonderWidgets lt em gt are great lt item gt lt item gt lt item gt Who lt em gt buys lt em gt WonderWidgets lt item gt lt slide lt slideshow gt Save a copy of this file as slideSamp1e01 xm1 so you can use it as the initial data structure when experimenting with XML programming operations Whiting Processing Instruc tions It sometimes makes sense to code application specific processing instructions in the XML data In this exercise you ll add a processing instruction to your slideSample xml file WRITING PROCESSING INSTRUCTIONS Note The file you ll create in this section is slideSamp1e 2 xm1 The browsable version is s ideSamp1e02 xm1 htm1 As you saw in Processing Instructions page 182 the format for a processing instruction is lt target data gt where target is the target application that is expected to do the processing and data is the instruction or information for
282. hat the parser does for each line For simplicity calls to the method ignorab1eWhiteSpace are not included lt priceList gt parser calls startElement lt coffee gt parser calls startElement lt name gt Mocha Java lt name gt parser calls startElement characters and endElement lt price gt 11 95 lt price gt parser calls startElement characters and endElement lt coffee gt parser calls endElement The default implementations of the methods that the parser calls do nothing so you need to write a subclass implementing the appropriate methods to get the functionality you want For example suppose you want to get the price per pound for Mocha Java You would write a class extending DefaultHandler the default implementation of ContentHandler in which you write your own imple mentations of the methods startElement and characters You first need to create a SAXParser object from a SAXParserFactory object You would call the method parse on it passing it the price list and an instance of your new handler class with its new implementations of the methods startEle ment and characters In this example the price list is a file but the parse method can also take a variety of other input sources including an InputStream object a URL and an InputSource object SAxXParserFactory factory SAXParserFactory newInstance SAXParser saxParser factory newSAxXParser saxParser parse priceList xml handler The result
283. he SAAJ Simple example perform the following steps 1 Mount the following filesystem lt INSTALL gt j2eetutorial examples jaxm saaj simple 2 An information dialog may appear stating that ReceivingServlet java cannot be converted to a servlet Click OK 3 Specify the following context root for the web module saaj simple 4 Right click the WEB INF node and choose Deploy from the menu THE JAXM TRANSLATOR EXAMPLE 5 Right click the WEB INF node and choose Execute from the menu If this doesn t work open a web browser and enter the following URL localhost 80 saaj simple index htm A web page appears with the following text This is a simple example of a roundtrip SAAJ message exchange Click here to send the message If you click the link another page appears with the following text Sent message check sent msg and received reply check reply msg You can find the files sent msg and reply msg in the following directory lt S1AS7_HOME gt domains domainl serverl config The J AXM Translator Example The JAXM Translator example uses a simple translation service to translate a given word into different languages If you have given the correct proxy host and proxy port the word you supply will be translated into French German and Ital ian Running this example generates the files request msg and reply msg in the server configuration directory Make sure you have followed the instructions
284. he UDDI test registry and the proxy host and proxy port of the sender If you are not sure what the values for these are you need to consult your system administrator or other person with that information Examining UddiPing We will go through the file UddiPing java a few lines at a time The first four lines of code import the packages used in the application import javax xml soap import javax xml messaging import java util import java io The next few lines begin the definition of the class UddiPing which starts with the definition of its main method The first thing it does is check to see if two arguments were supplied If not it prints a usage message and exits public class UddiPing public static void main String args try if Cargs length 2 System err printInC Usage MyUddiPing properties file business name System exit 1 THE UDDIPING EXAMPLE The following lines create a java util Properties file that contains the sys tem properties and the properties from the file uddi properties that is in the uddiping directory Properties myprops new Properties myprops load new FileInputStream args Properties sysprops System getPropertiesQ Enumeration it myprops propertyNames while C Cit hasMoreElements String s String it nextElementQ sysprops setProperty s myprops getProperty s The next four lines create a SOAPMessage object First the code gets a
285. he explanations and code examples that are presented in the tutorial section The overview looks at JAXM from three perspectives e Messages e Connections e Messaging providers Messages JAXM messages follow SOAP standards which prescribe the format for mes sages and also specify some things that are required optional or not allowed With the JAXM API you can create XML messages that conform to the SOAP specifications simply by making Java API calls The Structure of an XML Document Note For more complete information on XML documents see Understanding XML page 177 292 WEB SERVICES MESSAGING WITH JAXM An XML document has a hierarchical structure with elements subelements sub subelements and so on You will notice that many of the SAAJ classes and inter faces represent XML elements in a SOAP message and have the word element or SOAP or both in their names An element is also referred to as a node Accordingly the SAAJ API has the interface Node which is the base class for all the classes and interfaces that rep resent XML elements in a SOAP message There are also methods such as SOAPElement addTextNode Node detachNode and Node getValue which you will see how to use in the tutorial section What Is in a Message The two main types of SOAP messages are those that have attachments and those that do not Messages with No Attachments The following outline and Figure 10 1 show the very high level structur
286. he following code fragment shows what you might write to retrieve fault infor mation from a message you received In the code fragment newmsg is the SOAP Message object that has been sent to you Because a SOAPFau1t object must be part of the SOAPBody object the first step is to access the SOAPBody object Then the code tests to see if the SOAPBody object contains a SOAPFau1t object If so the code retrieves the SOAPFau1t object and uses it to retrieve its contents The convenience methods getFaultCode getFaultString and getFaultActor make retrieving the values very easy SOAPBody body newmsg getSOAPPart getEnvelope getBodyQ if body hasFaultQ SOAPFault newFault body getFaultQ String code newFault getFaultCodeQ String string newFault getFaultStringQ String actor newFault getFaultActorQ Next the code prints out the values it just retrieved Not all messages are required to have a fault actor so the code tests to see if there is one Testing whether the variable actor is nul works because the method getFaultActor returns null if a fault actor has not been set System out printInC SOAP fault contains System out printIn fault code code System out printIn fault string string if C actor null System out printinC fault actor actor CODE EXAMPLES 323 The final task is to retrieve the Detail object and get its DetailEntry objects The code uses the SOAPFault objec
287. he fully qualified host name instead of localhost Do not use https for the publishURL The IBM and Microsoft registries both have a considerable amount of data in them that you can perform queries on Moreover you do not have to register if you are only going to perform queries We have not included the URLs of the SAP registry feel free to add them If you want to publish to any of the public registries the registration pro cess for obtaining access to them is not difficult see Preliminaries Get ting Access to a Registry page 351 Each of them however allows you 374 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR to have only one organization registered at a time If you publish an orga nization to one of them you must delete it before you can publish another Since the organization that the JAXRPublish example publishes is ficti tious you will want to delete it immediately anyway The internal UDDI Server Registry gives you more freedom to experi ment with JAXR You can publish as many organizations to it as you wish However this registry comes with an empty database so you must publish organizations to it yourself before you can perform queries on the data Edit the following lines to specify the user name and password you obtained when you registered with the registry The default is the internal UDDI Server Registry default password Specify username and password if needed testuser testuser are d
288. he implementation of JAXR in the Sun ONE Application Server uses a simple file based approach to provide taxonomies to the JAXR client These files are read at run time when the JAXR provider starts up The taxonomy structure for the implementation of JAXR in the Sun ONE Appli cation Server is defined by the JAXR Predefined Concepts DTD which is declared both in the file jaxrconcepts dtd and in XML schema form in the file jaxrconcepts xsd The file jaxrconcepts xm contains the taxonomies for the implementation of JAXR in the Sun ONE Application Server All these files are contained in the file lt S1STUDIO_HOME gt jwsdp common 1lib jaxr ri jar The jaxr ri jar file also includes files that define the well known tax onomies that the implementation of JAXR in the Sun ONE Application Server uses naics xml 1so3166 xml and unspsc xml USING TAXONOMIES IN JAXR CLIENTS 367 The entries in the jaxrconcepts xm file look like this lt PredefinedConcepts gt lt JAXRClassificationScheme id schId name schName gt lt JAXRConcept id schId conCode name conName parent parentId code conCode gt lt JAXRConcept gt lt JAXRClassificationScheme gt lt PredefinedConcepts gt The taxonomy structure is a containment based structure The element Pre definedConcepts is the root of the structure and must be present The JAXR ClassificationScheme element is the parent of the structure and the JAXRConcept elements are children and gr
289. he jsp forward element lt jsp forward page main jsp gt Note that if any data has already been returned to a client the jsp forward ele ment will fail with an I1legalStateException jsp param Hement When an include or forward element is invoked the original request object is provided to the target page If you wish to provide additional data to that page you can append parameters to the request object with the jsp param element lt jsp include page gt lt jsp param name paraml value valuel gt lt jsp include gt Including an Applet You can include an applet or JavaBeans component in a JSP page by using the jsp plugin element This element generates HTML that contains the appropri ate client browser dependent constructs lt object gt or lt embed gt that will result in the download of the Java Plug in software if required and client side compo nent and subsequent execution of any client side component The syntax for the jsp plugin element is as follows lt jsp plugin type bean applet code objectCode codebase objectCodebase align alignment archive archiveList height height hspace hspace INCLUDING AN APPLET jreversion Jjreversion name componentName vspace vspace width width nspluginurl url jepluginurl url gt lt jsp params gt lt jsp param name paramName value paramValue gt lt jsp params gt lt jsp fall
290. he object such as HTTP or FTP host specifies the Internet name of the targeted host and localinfo is a string often a file name passed to the pro tocol handler on the remote host URL path The part of a URL passed by an HTTP request to invoke a servlet A URL path consists of the Context Path Servlet Path Path Info where e Context Path is the path prefix associated with a servlet context that this servlet is a part of If this context is the default context rooted at the base of the Web server s URL namespace the path prefix will be an empty string Otherwise the path prefix starts with a character but does not end with a character e Servlet Path is the path section that directly corresponds to the mapping which activated this request This path starts with a character e Path Info is the part of the request path that is not part of the Context Path or the Servlet Path URN Uniform Resource Name A unique identifier that identifies an entity but doesn t tell where it is located A system can use a URN to look up an entity locally before trying to find it on the Web It also allows the Web location to change while still allowing the entity to be found user security An individual or application program identity that has been authenticated A user can have a set of roles associated with that identity which entitles them to access all resources protected by those roles user data constraint Indicates how data b
291. he organization name For example the following code fragment 357 358 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR performs a case sensitive search for organizations whose names contain qString Collection findQualifiers new ArrayListQ findQualifiers add FindQualifier CASE_SENSITIVE_MATCH Collection namePatterns new ArrayListQ namePatterns add qString Find orgs with name containing qString BulkResponse response bqm findOrganizations findQualifiers namePatterns null null null null Collection orgs response getCollection Finding Organizations by Classifc ation To find organizations by classification you need to establish the classification within a particular classification scheme and then specify the classification as an argument to the findOrganizations method The following code fragment finds all organizations that correspond to a particu lar classification within the NAICS taxonomy You can find the NAICS codes at http www census gov epcd naics naicscod txt ClassificationScheme cScheme bqm findClassi ficationSchemeByName null1 ntis gov naics Classification classification blcm createClassification cScheme Snack and Nonalcoholic Beverage Bars 722213 Collection classifications new ArrayListQ classifications add classification make JAXR request BulkResponse response bqm findOrganizations null null classifications null null null Co
292. hen you create a DataHandler object initialized with the URL object and pass it to the method createAttachmentPart URL url new URLC http greatproducts com gizmos img jpg DataHandler dh new DataHandler ur1 AttachmentPart attachment message createAttachmentPart dh attachment setContentIdC gyro_image message addAttachmentPart attachment You might note two things about the previous code fragment First it sets a header for Content ID with the method setContentId This method takes a String that can be whatever you like to identify the attachment Second unlike the other methods for setting content this one does not take a String for Con tent Type This method takes care of setting the Content Type header for you which is possible because one of the things a DataHandler object does is deter mine the data type of the file it contains Accessing an AttachmentPart Object If you receive a message with attachments or want to change an attachment to a message you are building you will need to access the attachment When it is given no argument the method SOAPMessage getAttachments returns a java util Iterator object over all the AttachmentPart objects in a message The following code prints out the content of each AttachmentPart object in the SOAPMessage object message java util Iterator it message getAttachments while Cit hasNext Q AttachmentPart attachment AttachmentPart it nextQ Object content a
293. her The output window should display mm dd yy today s date mm dd yy 60 days from today Mocca 4 00 Wake Up Call 5 50 French Roast 5 00 Kona 6 50 Registering the J AX RPC Service 1 Start the UDDI Registry a Select the Runtime tab of the Explorer b Expand the UDDI Server Registry node c Right click the Internal UDDI Registry node and choose Start Server 2 Register the service with the Registry Server a Select the Filesystems tab of the Explorer b In the jaxrpc subdirectory expand the registry package c Execute the OrgPublisher program d The registration process can take some time so wait until you see the following output before proceeding Created connection to registry Got registry service query manager and life cycle manager Established security credentials Organization saved Organization key is XXXXXXXX 420 THE COFFEE BREAK APPLICATION Later on you can remove the JAX RPC service from the registry by executing OrgRemover Deploying the J AXM Service To build and deploy the JAXM service 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples cb jaxm service 2 Right click the WEB INF directory and choose Deploy Testing the J AXM Service To test the JAXM service you run the test programs TestPriceListRequest or TestOrderRequest in the lt INSTALL gt j2eetutorial examples cb jaxm test directory Note The test programs assume that you have deployed the JAXM
294. her than directly to the target document updating the address book then automatically changes any links that use it XML Base This standard defines an attribute for XML documents that defines a base address that is used when evaluating a relative address specified in the docu ment So for example a simple file name would be found in the base address directory XPointer In general the XLink specification targets a document or document segment using its ID The XPointer specification defines mechanisms for addressing into the internal structures of XML documents without requiring the author of the document to have defined an ID for that segment To quote the spec it provides for reference to elements character strings and other parts of XML documents whether or not they bear an explicit ID attribute For more information on the XML _ Linking standards see http www w3 org XML Linking XHTML The XHTML specification is a way of making XML documents that look and act like HTML documents Since an XML document can contain any tags you care to define why not define a set of tags that look like HTML That s the thinking behind the XHTML specification at any rate The result of this specification is a document that can be displayed in browsers and also treated as XML data The data may not be quite as identifiable as pure XML but it will be a heck of a lot easier to manipulate than standard HTML because
295. hin a declaration or scriptlet The following scriptlet creates the bookstore shopping cart and stores it as a session attribute lt ShoppingCart cart C ShoppingCart session getAttributeC cart If the user has no cart create a new one if cart null cart new ShoppingCart session setAttribute cart cart gt If the shopping cart object conforms to JavaBeans conventions JSP pages can use JSP elements to create and access the object For example the Duke s Book store pages bookdetails jsp catalog jsp and showcart jsp replace the scriptlet with the much more concise JSP useBean element lt jsp useBean id cart class cart ShoppingCart scope session gt Creating and Using a JavaBeans Component You declare that your JSP page will use a JavaBeans component using either one of the following formats lt jsp useBean id beanName class fully_qualified_classname scope scope gt 106 JAVASERVER PAGES TECHNOLOGY or lt jsp useBean id beanName class fully_qualified_classname scope scope gt lt jsp setProperty gt lt jsp useBean gt The second format is used when you want to include jsp setProperty state ments described in the next section for initializing bean properties The jsp useBean element declares that the page will use a bean that is stored within and accessible from the specified scope which can be application session request or page If no such bean e
296. hin c set The x out tag converts the node to a String and c set gt then stores the String as a 167 168 JAVASERVER PAGES STANDARD TAG LIBRARY scoped attribute For example bookdetails jsp stores a scoped attribute con taining a book price which is later fed into a fmt tag as follows lt c set var price gt lt x out select abook price gt lt c set gt lt h4 gt lt fmt message key ItemPrice gt lt fmt formatNumber value price type currency gt The other option which is more direct but requires that the user have more knowledge of XPath is to coerce the node to a String manually using XPath s string function lt x set var price select string abook price gt How Contol Tags The XML flow control tags parallel the behavior described in Flow Control Tags page 161 for the XPath expression language The JSP page catalog jsp uses the forEach tag to display all the books con tained in booklist as follows lt x forEach var book select app1icationScope booklist books gt lt tr gt lt c set var bookId gt lt x out select book id gt lt c set gt lt td bgcolor ffffaa gt lt ciurl var url value bookdetails gt lt C iparam name bookId value bookId gt lt Ciparam name Clear value 0 gt lt c url gt lt a href lt c out value url gt gt lt strong gt lt x out select book title gt amp nbsp lt strong gt lt a gt lt td gt lt
297. hings that are more usefully defined as elements the title element and things that are more suitable as attributes the type attribute The visibility heuristic is pri marily at work here The title is something the audience will see So it is an ele ment The type on the other hand is something that never gets presented so it is an attribute Another way to think about that distinction is that an element is a container like a bottle The type is a characteristic of the container is it tall or short wide or narrow The title is a characteristic of the contents water milk or tea These are not hard and fast rules of course but they can help when you design your own XML structures Adding HIML Style Text Since XML lets you define any tags you want it makes sense to define a set of tags that look like HTML The XHTML standard does exactly that in fact You ll see more about that towards the end of the SAX tutorial For now type the WRITING A SIMPLE XML FILE 203 text highlighted below to define a slide with a couple of list item entries that use an HTML style lt em gt tag for emphasis usually rendered as italicized text lt TITLE SLIDE gt lt slide type all1 gt lt title gt Wake up to WonderWidgets lt title gt lt slide gt lt OVERVIEW gt lt slide type all1 gt lt title gt Overview lt title gt lt item gt Why lt em gt WonderWidgets lt em gt are great lt item gt lt item gt Who l
298. htm1 e The JSTL 1 0 Specification Understanding XML Eric Armstrong Tiss chapter describes the Extensible Markup Language XML and its related specifications It also gives you practice in writing XML data so you become comfortably familiar with XML syntax Note The XML files mentioned in this chapter can be found in lt J2EE_HOME gt doc tutorial examples xml samples Introduction to XML This section covers the basics of XML The goal is to give you just enough infor mation to get started so you understand what XML is all about You ll learn about XML in later sections of the tutorial We then outline the major features that make XML great for information storage and interchange and give you a general idea of how XML can be used What Is XML XML is a text based markup language that is fast becoming the standard for data interchange on the Web As with HTML you identify data using tags identifiers enclosed in angle brackets like this lt gt Collectively the tags are known as markup 177 178 UNDERSTANDING XML But unlike HTML XML tags identify the data rather than specifying how to dis play it Where an HTML tag says something like display this data in bold font lt b gt lt b gt an XML tag acts like a field name in your program It puts a label on a piece of data that identifies it for example lt message gt lt message gt Note Since identifying the d
299. hyphens NMTOKEN underscores and colons NMTOKENS A space separated list of names The name of a DTD specified notation which describes a NOTATION 2 0 non XML data format such as those used for image files This is a rapidly obsolescing specification which will be discussed in greater length towards the end of this section 217 218 UNDERSTANDING XML When the attribute type consists of a parenthesized list of choices separated by vertical bars the attribute must use one of the specified values For an example add the text highlighted below to the DTD lt ELEMENT slide title item gt lt ATTLIST slide type tech exec all IMPLIED gt lt ELEMENT title PCDATA gt lt ELEMENT item PCDATA item gt This specification says that the slide element s type attribute must be given as type tech type exec or type al1 No other values are acceptable DTD aware XML editors can use such specifications to present a pop up list of choices The last entry in the attribute specification determines the attributes default value if any and tells whether or not the attribute is required Table 7 4 shows the possible choices Table 7 4 Attribute Specification Parameters REQUIRED The attribute value must be specified in the document IMPLIED The value need not be specified in the document If it isn t the application will have a default value it uses defaultValue The
300. ial http java sun com products jndi tutorial index htm Java Transaction API The Java Transaction API JTA provides a standard interface for demarcating transactions The J2EE architecture provides a default auto commit to handle transaction commits and rollbacks An auto commit means that any other appli cations viewing data will see the updated data after each database read or write operation However if your application performs two separate database access operations that depend on each other you will want to use the JTA API to demarcate where the entire transaction including both operations begins rolls back and commits 19 20 OVERVIEW JavaMail API J2EE applications can use the JavaMail API to send e mail notifications The JavaMail API has two parts an application level interface used by the applica tion components to send mail and a service provider interface The J2EE plat form includes JavaMail with a service provider that allows application components to send Internet mail JavaBeans Activation Framework The JavaBeans Activation Framework JAF is included because JavaMail uses it It provides standard services to determine the type of an arbitrary piece of data encapsulate access to it discover the operations available on it and create the appropriate JavaBeans component to perform those operations Java API for XML Processing The Java API for XML Processing JAXP supports the processing of XM
301. iated with those services Iterator orgIter orgs iteratorQ while CorgIter hasNext Organization org Organization orgIter nextQ Collection services org getServices Iterator svcIter services iterator while svcIter hasNextQ Service svc Service svcIter nextQ Collection serviceBindings svc getServiceBindings Iterator sbIter serviceBindings iteratorQ while sbIter hasNextQ ServiceBinding sb ServiceBinding sbIter nextQ MANAGING REGISTRY DATA Managing Registry Data If a client has authorization to do so it can submit data to a registry modify it and remove it It uses the BusinessLifeCycleManager interface to perform these tasks Registries usually allow a client to modify or remove data only if the data is being modified or removed by the same user who first submitted the data Getting Authonzation from the Registry Before it can submit data the client must send its user name and password to the registry in a set of credentials The following code fragment shows how to do this String username myUserName String password myPassword Get authorization from the registry PasswordAuthentication passwdAuth new PasswordAuthentication username password toCharArray Set creds new HashSet creds add passwdAuth connection setCredentials creds Creating an Organization The client creates the organization and populates it with data before saving it
302. ibute values JSTL EXPRESSION LANGUAGE In the JSTL RT tag library expressions are specified in the page s scripting lan guage This is exactly how things currently work in current tag libraries In the JSTL EL tag library expressions are specified in the JSTL expression lan guage An expression is a String literal in the syntax of the EL When using the EL tag library you cannot pass a scripting language expression for the value of an attribute This rule makes it possible to validate the syntax of an expression at translation time J SIL Expression Language The JSTL expression language is responsible for handling both expressions and literals Expressions are enclosed by the characters For example lt c if test beanl a lt 3 gt Any value that does not begin with is treated as a literal that is parsed to the expected type using the PropertyEditor for the expected type lt c if test true gt Literal values that contain the characters must be escaped as follows lt mytags example attrl an expression is true gt Atinbutes Attributes are accessed by name with an optional scope Properties of attributes are accessed using the operator and may be nested arbitrarily The EL unifies the treatment of the and operators Thus expr a expr b is equivalent to expr a Lexpr b To evaluate expr a expr b evaluate expr a into value a and evaluate expr b into value b e If value a is a
303. ic Counter counter Q public synchronized int getCounter Q return counter public synchronized int setCounter Cint c counter C return counter public synchronized int incCounter return counter Accessing Databases Data that is shared between Web components and is persistent between invoca tions of a Web application is usually maintained by a database Web components use the JDBC 2 0 API to access relational databases The data for the bookstore application is maintained in a database and accessed through the helper class 58 JAVA SERVLET TECHNOLOGY database BookDB For example ReceiptServlet invokes the BookDB buy Books method to update the book inventory when a user makes a purchase The buyBooks method invokes buyBook for each book contained in the shopping cart To ensure the order is processed in its entirety the calls to buyBook are wrapped in a single JDBC transaction The use of the shared database connec tion is synchronized via the get release Connection methods public void buyBooks ShoppingCart cart throws OrderException Collection items cart getItems Iterator i items iteratorQ try getConnection con setAutoCommit false while i hasNextQ ShoppingCartItem sci CShoppingCartItem i nextQ BookDetails bd BookDetails sci getItemQ String id bd getBookIdQ int quantity sci getQuantityQ buyBook id quantity con commit con setAu
304. iceList method of JAXMPriceListRequest which follows the DTD price list dtd The getPriceList method begins by creating the connection that will be used to send the request Then it gets the default MessageFactory object so that it can create the SOAPMessage object msg SOAPConnectionFactory scf SOAPConnectionFactory newlInstance SOAPConnection con scf createConnection MessageFactory mf MessageFactory newInstance SOAPMessage msg mf createMessage 403 404 THE COFFEE BREAK APPLICATION The next step is to access the message s SOAPEnvelope object which will be used to create a Name object for each new element that is created It is also used to access the SOAPBody object to which the message s content will be added SOAPPart part msg getSOAPPart SOAPEnvelope envelope part getEnvelope SOAPBody body envelope getBodyQ The file price list dtd specifies that the top most element inside the body is request prices and that it contains the element request The text node added to request is the text of the request being sent Every new element that is added to the message must have a Name object to identify it which is created by the Envelope method createName The following lines of code create the top level element in the SOAPBody object body The first element created in a SOAPBody object is always a SOAPBodyElement object Name bodyName envelope createName request prices RequestPrices
305. id orgKey getIdQ System out printInC Organization key was id J AXM Distnbutor Service The JAXM distributor service and the Coffee Break have made arrangements regarding their exchange of XML documents These arrangements include what kinds of messages they will send the form of those messages and what kind of JAXM messaging they will do If they had agreed to do one way messaging they would also have had to use messaging providers that talk to each other and had to use the same profile In this scenario the parties have agreed to use request response messaging so a messaging provider is not needed The Coffee Break server sends two kinds of messages e Requests for current wholesale coffee prices e Customer orders for coffee The JAXM coffee supplier responds with two kinds of messages e Current price lists e Order confirmations 394 THE COFFEE BREAK APPLICATION All of the messages they send conform to an agreed upon XML structure which is specified in a DTD for each kind of message This allows them to exchange messages even though they use different document formats internally The four kinds of messages exchanged by the Coffee Break server and the JAXM distributor are specified by the following DTDs e request prices dtd e price list dtd e coffee order dtd e confirm dtd These DTDs may be found at lt INSTALL gt j2eetutorial examples cb jaxm dtds The dtds directory also contains a sample of what the
306. ied to findOrganizations because nu11 is supplied for the third fifth and sixth parameters those criteria are not used to limit the search The first second and fourth arguments are all Collection objects with findQualifiers and namePatterns being defined here The only element in findQualifiers is a String specifying that no organization be returned unless its name is a case sensitive match to one of the names in the namePatterns parameter This parameter which is also a Collection object SAMPLE SCENARIO with only one element says that businesses with Coffee in their names are a match The other Collection object is classifications which was defined when The Coffee Break registered itself The previous code fragment in which the industry for The Coffee Break was provided is an example of defining clas sifications BusinessQueryManager bqm rs getBusinessQueryManager Define find qualifiers Collection findQualifiers new ArrayListQ findQualifiers add FindQualifier CASE_SENSITIVE_MATCH Collection namePatterns new ArrayListQ namePatterns add Coffee Find orgs with name containing Coffee Find using only the name and the classifications BulkResponse response bqm findOrganizations findQualifiers namePatterns null classifications null null Collection orgs response getCollection JAXR also supports using an SQL query to search a registry This is done using a DeclarativeQueryM
307. iented Web services with the Java API for XML based RPC JAX RPC e Defining message oriented Web services with the Java API for XML Messaging JAXM and Soap with Attachments API for Java SAAJ e Publishing and discovering RPC oriented Web services The Java API for XML Registries JAXR e Case Study The Coffee Break Application chapter describes an application that ties together most of the APIs discussed in this tutorial About the Examples If you are viewing this online you need to download The J2EE Tutorial for the Sun ONE Platform from http java sun com j2ee 1 3 download html tutorial Once you have unzipped the tutorial bundle the example source code is in the lt INSTALL gt j2eetutorial examples directory with subdirectories for each of the technologies Note that lt INSTALL gt is the directory in which you unzipped the bundle To build the examples you need a copy of Sun ONE Studio 4 update 1 Enter prise Edition for Java You download a free trial copy of this edition of Studio from http wwws sun com software sundev jde index htm To deploy and run the examples you need a copy of Sun ONE Application Server 7 Platform Edition or Standard Edition Sun ONE Application Server 7 Platform Edition is free for development and deployment but does not allow remote management Sun ONE Application Server 7 Standard Edition is free for development and evaluation and supports remote management You can down lo
308. ients to execute procedures on other systems In JAX RPC a remote procedure call is represented by an XML based protocol such as SOAP The SOAP specification defines envelope structure encoding rules and a convention for representing remote procedure calls and responses These calls and responses are transmitted as SOAP messages over HTTP In this release JAX RPC relies on SOAP 1 1 and HTTP 1 1 Although JAX RPC relies on complex protocols the API hides this complexity from the application developer On the server side the developer specifies the remote procedures by defining methods in an interface written in the Java pro gramming language The developer also codes one or more classes that imple ment those methods Client programs are also easy to code A client creates a proxy a local object representing the service and then simply invokes methods on the proxy With JAX RPC clients and Web services have a big advantage the platform independence of the Java programming language In addition JAX RPC is not restrictive a JAX RPC client can access a Web service that is not running on the Java platform and vice versa This flexibility is possible because JAX RPC uses technologies defined by the World Wide Web Consortium W3C HTTP SOAP 269 270 BUILDING WEB SERVICES WITH JAX RPC and the Web Service Description Language WSDL WSDL specifies an XML format for describing a service as a set of endpoints operating on messages I
309. iew Controller design pattern The Dispatcher servlet is the controller It examines the request URL creates and initializes model JavaBeans components and dis patches requests to view JSP pages The JavaBeans components contain the business logic for the application they call the Web services and perform com putations on the data returned from the services The JSP pages format the data 402 THE COFFEE BREAK APPLICATION stored in the JavaBeans components The mapping between JavaBeans compo nents and pages is summarized in Table 12 1 Table 12 1 Model and View Components JSP Page JavaBeans Component Update order data orderForm ShoppingCart Update delivery and billing data checkoutForm CheckoutFormBean Display order confirmation checkoutAck OrderConfi rmations To browse the code for the Coffee Break server in the IDE mount the filesystem lt INSTALL gt j2eetutorial examples cb cbservice Service Oriented J avaBeans Components The Coffee Break server uses the following JavaBeans components to represent data returned from the JAX RPC and JAXM Web services e AddressBean shipping information for customer e ConfirmationBean order id and ship date e CustomerBean customer contact information e LineItemBean order item e OrderBean order id customer address list of line items total price e PriceItemBean price list entry coffee name and wholesale price e PriceListBean price list The compon
310. ildren with that name In this example however you need to retrieve all elements and keep drilling down until you get to the elements that contain text content Here is the basic pattern that is repeated for drilling down Iterator iterl replyBody getChildElements while Citerl hasNextQ SOAPBodyElement bodyElement CSOAPBodyElement iterl nextQ Iterator iter2 bodyElement getChildElementsQ while Citer2 hasNextQ 331 332 WEB SERVICES MESSAGING WITH JAXM The method getChildElements returns the elements in the form of a java util Iterator object You access the child elements by calling the method next on the Iterator object The method Iterator hasNext can be used in a while loop because it returns true as long as the next call to the method next will return a child element The loop ends when there are no more child elements to retrieve An immediate child of a SOAPBody object is a SOAPBodyElement object which is why calling iterl next returns a SOAPBodyElement object Children of SOAP BodyElement objects and all child elements from there down are SOAPElement objects For example the call iter2 next returns the SOAPElement object child2 Note that the method Iterator next returns an Object which has to be narrowed cast to the specific kind of object you are retrieving Thus the result of calling iter1 next is cast to a SOAPBodyElement object whereas the results of calling iter2 next iter3 next and so on are
311. ile to specify the correct pathname for the postalconcepts xml file 1 Right click the file postal properties and choose the Edit menu item 2 Specify the correct pathname for the postalconcepts xml1 file On a UNIX system the pathname may be relative but on a Windows system it must be absolute and must be specified using double backslashes For example you might enter the following all on one line com sun xml registry userlTaxonomyFi lenames D Sun AppServer7 docs tutorial examples jaxr postalconcepts xml Running the J AXRPublishPostal Example The JAXRPublishPostal example uses the postal properties file to set the system property com sun xml registry userTaxonomyFi lenames to the cor rect location of the postalconcepts xm1 file You need to specify this file and the UUID string of the classification scheme as command line arguments 1 Click the JAXRPublishPostal file in the Filesystems tab 2 In the property window for the file choose the Execution tab 3 Click Arguments then double click the ellipsis to bring up the property editor 4 Enter the pathname of the postal properties file and the UUID string of the classification scheme On a Windows system you must specify the full pathname For example you might specify the following all on one line D MyTutorial j2eetutorial examples jaxr postal properties uuid f2be7262 aff2 be76 b3fa ddd3e4e600Ff5 379 380 5 6 PUBLISHING AND DISCOVERING
312. ill occur if the PointBase server hasn t been started In the log you will see the following 12 Feb 2003 12 28 14 INFO 4944 CORE3282 stdout Couldn t create connection SQL server rejected establishment of SQL connection PointBase 12 Feb 2003 12 28 14 INFO 4944 CORE3282 stdout SERVLET LIFE CYCLE Couldn t create databaseCouldn t open connection to data base SQL server rejected establishment of SQL connection PointBase If you have the database server running but the application server can t communicate with it due to firewall interference then you will see the fol lowing error 12 Feb 2003 16 15 14 INFO C 1952 CORE3282 stdout Couldn t create connection nul1 12 Feb 2003 16 15 14 INFO C 1952 CORE3282 stdout Couldn t create databaseCouldn t open connection to data base null If you have not defined a data source that references the PointBase data base see Defining a Data Source in Sun ONE Application Server 7 page 43 you will see the following 13 Feb 2003 10 32 23 INFO C 3128 CORE3282 stdout Couldn t create connection BookDB not found e BookNotFoundException Returned if a book can t be located in the bookstore database This will occur if the PointBase database server has crashed e BooksNotFoundException Returned if the bookstore data can t be retrieved This will occur if the PointBase database server has crashed Serviet Life Cycle The life cycle of a servlet is c
313. ilter you retrieve them from the FilterConfig object passed to init The Duke s Bookstore application uses the filters HitCounterFilter and OrderFilter to increment and log the value of a counter when the entry and receipt servlets are accessed In the doFilter method both filters retrieve the servlet context from the filter configuration object so that they can access the counters stored as context attributes After the filters have completed application specific processing they invoke doFilter on the filter chain object passed into the original doFilter method The elided code is discussed in the next section public final class HitCounterFilter implements Filter private FilterConfig filterConfig null public void init FilterConfig filterConfig throws ServletException this filterConfig filterConfig public void destroy this filterConfig null public void doFilter ServletRequest request ServletResponse response FilterChain chain throws IOException ServletException if CfilterConfig null return StringWriter sw new StringWriterQ PrintWriter writer new PrintWriter sw Counter counter Counter filterConfig getServletContext getAttribute hitCounter writer printiInQd PROGRAMMING CUSTOMIZED REQUESTS AND RESPONSES writer printIn writer printInC The number of hits is counter incCounter writer printIn Log the resulting string w
314. ilter and OrderFilter which were discussed in Filtering Requests and Responses page 64 The filters store a counter as a context attribute Recall from Controlling Concurrent Access to Shared Resources page 56 that the counter s access methods are synchronized to prevent incompatible operations by servlets that are running concurrently A filter retrieves the counter object with the context s getAttribute method The incremented value of the counter is recorded with the context s 10g method public final class HitCounterFilter implements Filter private FilterConfig filterConfig null public void doFilter ServletRequest request ServletResponse response FilterChain chain throws IOException ServletException StringWriter sw new StringWriterQ PrintWriter writer new PrintWriter sw ServletContext context filterConfig getServletContextQ Counter counter Counter context getAttributeC hitCounter 76 JAVA SERVLET TECHNOLOGY writer printInC The number of hits is counter incCounter context 1og sw getBuffer toStringO Maintaining Client State Many applications require a series of requests from a client to be associated with one another For example the Duke s Bookstore application saves the state of a user s shopping cart across requests Web based applications are responsible for maintaining such state called a session because the HTTP protocol is stateless To support applications
315. in embedded URLs that point to other Web components For example ShowCart Servlet indirectly invokes the CatalogServlet through the embedded URL bookstorel catalog A Web component can also directly invoke another resource while it is execut ing There are two possibilities it can include the content of another resource or it can forward a request to another resource To invoke a resource available on the server that is running a Web component you must first obtain a RequestDispatcher object using the getRequestDis patcher URL method You can get a RequestDispatcher object from either a request or the Web con text however the two methods have slightly different behavior The method takes the path to the requested resource as an argument A request can take a rel ative path that is one that does not begin with a but the Web context requires an absolute path If the resource is not available or if the server has not imple mented a RequestDispatcher object for that type of resource getRequestDis patcher will return null Your servlet should be prepared to deal with this condition Including Other Resources in the Response It is often useful to include another Web resource for example banner content or copyright information in the response returned from a Web component To INCLUDING OTHER RESOURCES IN THE RESPONSE include another resource invoke the include method of a RequestDispatcher object include request
316. in Changing Server Permissions page 325 before you begin To deploy and run the JAXM Translator example perform the following steps 1 Mount the following filesystem lt INSTALL gt j2eetutorial examples jaxm jaxm translator 2 An information dialog may appear stating that ReceivingServlet java cannot be converted to a servlet Click OK 3 Specify the following context root for the web module jaxm translator 4 Right click the WEB INF node and choose Deploy from the menu 5 Right click the WEB INF node and choose Execute from the menu If this doesn t work open a web browser and enter the following URL 342 WEB SERVICES MESSAGING WITH JAXM localhost 80 jaxm translator index htm A web page with the header Translator Sample Application appears 6 Enter the proxy host and port for your system in the text fields provided 7 Enter the text to be translated in the field provided 8 Choose the In SOAPBody or As Attachments radio button and click Trans late 9 A web page appears with the word translated into the three languages 10 Use the browser s back button to run the example again Check reply msg after getting the reply in the SOAP body and again after get ting the reply as an attachment to see the difference in what is sent as a reply You can find the files request msg and reply msg in the following directory lt S1AS7_HOME gt domains domain1 serverl1 config The J AXM Tags Example The JA
317. inating redundancies 236 EMPTY 214 encoding 181 endpoint 308 enterprise beans 9 development role 16 types 10 Enterprise Information Systems See EIS entities 181 defining in DTD 219 external 236 included in line 183 parameter 225 parsed 222 predefined 207 reference 236 referencing binary 223 referencing external 221 unparsed 222 useful 220 INDEX 463 examples downloading ix location ix exceptions mapping to web resources 32 web components 32 Extensible Markup Language See XML F fault code 320 retrieving information 322 string 320 Filter 65 filter chains 65 71 filters 64 defining 65 mapping to Web components 70 mapping to Web resources 70 71 72 overriding request methods 67 overriding response methods 67 response wrapper 67 findClassificationSchemeByName method 363 367 findConcepts method 359 findOrganization method 357 forward 74 fully qualified 305 G GenericServlet 48 getChildElements method 331 464 INDEX getParameter 60 getRequestDispatcher 72 getServletContext 75 getSession 76 H headers 300 adding content 312 Content Id 316 Content Location 316 Content Type 316 HTML 178 HTTP 269 setting proxies 354 HTTP protocol 427 HTTP requests 60 428 methods 428 query strings 61 See also requests URLs 60 HTTP responses 62 428 See also responses status codes 32 428 mapping to web resources 32 HttpServlet 48 HttpServletRequest 60 HttpServletResponse 62 HttpSession 76 I I
318. ind of thing you ll see Wake up to WonderWidgets Note that the product name has been substituted for the entity reference To finish save a copy of the file as s ideSamp1eQ6 xml Additional Useful Entities Here are several other examples for entity definitions that you might find useful when you write an XML document lt ENTITY ldquo amp 147 gt lt Left Double Quote gt lt ENTITY rdquo amp 148 gt lt Right Double Quote gt lt ENTITY trade amp 153 gt lt Trademark Symbol TM gt lt ENTITY rtrade amp 174 gt lt Registered Trademark R gt lt ENTITY copyr amp 169 gt lt Copyright Symbol gt DEFINING ATTRIBUTES AND ENTITIES IN THE DTD 221 Referencing Extemal Entities You can also use the SYSTEM or PUBLIC identifier to name an entity that is defined in an external file You ll do that now Note The XML defined here is contained in slideSamp1eQ7 xm1 and in copy right xml The browsable versions are slideSamp1leQ 7 xm1 htm and copy right xm1 htm1 To reference an external entity add the text highlighted below to the DOCTYPE statement in your XML file lt DOCTYPE slideshow SYSTEM slideshow dtd lt ENTITY product WonderWidget gt lt ENTITY products WonderwWidgets gt lt ENTITY copyright SYSTEM copyright xm1 gt gt This definition references a copyright message contained in a file named copy right xm1 Create that file
319. iners 13 loading and initializing serv lets 51 Web module 28 Web resources mapping filters to 70 71 72 web resources 28 Web services 239 250 251 creating 253 discovering 266 RPC based 250 writing a client application 254 Web Services Description Lan guage See WSDL web xml file 405 well formed 203 204 World Wide Web Consortium See W3C WSDL 251 266 270 287 documents 252 using to find organizations 358 377 X XHTML 195 202 XLink 194 XML 20 177 240 269 270 comments 180 content 181 designing a data structure 233 documents 216 292 elements 292 linking 194 prolog 181 registries establishing security cre dentials 361 transforming a DOM tree to 248 XML Base 195 XML data 216 XML Schema 193 XML Stylesheet Language Trans formations See XSLT XPATH 191 XPointer 195 XSL 191 247 XSLT 191 242 247 XTM 196
320. ines are what the SOAPBodyElement gltp in your code represents Get LastTradePrice is its local name m is its namespace prefix and http wombat ztrade com is its namespace URI JAXM code Name name envelope createName symbol SOAPElement symbol gltp addChildElement name symbol addTextNodeC SUNW 308 WEB SERVICES MESSAGING WITH JAXM XML it produces lt symbo1l gt SUNW lt symbol gt The String SUNW is the message content that your recipient the stock quote service receives Sending a Message A standalone client uses a SOAPConnection object and must therefore use the SOAPConnection method call to send a message This method takes two argu ments the message being sent and the destination to which the message should go This message is going to the stock quote service indicated by the URL object endpoint java net URL endpoint new URL http wombat ztrade com quotes SOAPMessage response con call message endpoint Your message sent the stock symbol SUNW the SOAPMessage object response should contain the last stock price for Sun Microsystems which you will retrieve in the next section A connection uses a fair amount of resources so it is a good idea to close a con nection as soon as you are through using it con close Getting the Content of a Message The initial steps for retrieving a message s content are the same as those for giv ing content to a message You
321. intain con versational state across methods and transactions If a session bean main tains state then the EJB container manages this state if the object must be removed from memory However the session bean object itself must manage its own persistent data 449 SGML Standard Generalized Markup Language The parent of both HTML and XML However while HTML shares SGML s propensity for embedding presentation information in the markup XML is a standard that allows infor mation content to be totally separated from the mechanisms for rendering that content SOAP Simple Object Access Protocol SOAP with Attachments API for Java SAAJ The basic package for SOAP messaging which contains the API for creating and populating a SOAP message SSL Secure Socket Layer A security protocol that provides privacy over the Internet The protocol allows client server applications to communicate in a way that cannot be eavesdropped or tampered with Servers are always authenticated and clients are optionally authenticated SQL Structured Query Language The standardized relational database language for defining database objects and manipulating data SQL J A set of standards that includes specifications for embedding SQL state ments in methods in the Java programming language and specifications for calling Java static methods as SQL stored procedures and user defined func tions An SQL checker can detects errors in static SQL statements at pro
322. io 4 Enterprise Edition for Java with Application Server 7 Tutorial 2 Right click Sun ONE Application Server 7 in the Installed Servers list and choose Add Admin Server 3 Type the host and port 4848 of the application server s admin server 4 Type the user name and password you provided when you installed the application server and click OK 5 Right click the admin server just created and choose Create a Server Instance 6 Type the host and port 80 of the application server and click OK 33 INTRODUCTION TO WEB APPLICATIONS 3 Verify that the Sun ONE Application Server 7 is the default server a In the Runtime pane of the Explorer expand the nodes Server Regis try Default Servers b Verify that beneath Default Servers there is a node for Web Tier Appli cations serverl host port If this node is not displayed 1 Right click Web Tier Applications and choose Set Default Server 2 Select the server instance you created in step 2 and click OK 4 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web hel lol 5 Expand the he1101 node 6 Right click the WEB INF directory and choose Deploy Listing Deployed Web Modules You can list deployed Web modules with the application server administration tool or the IDE To list all Web modules currently deployed on the application server with the administration tool 1 Open the URL http localhost 4848 admin in a browser 2 Select the s
323. ional block execution by the embedded when sub tags It renders the body of the first when tag whose test condition evaluates to true If none of the test conditions of nested when tags evaluate to true then the body of an otherwise tag is evaluated if present For example the following sample code shows how to render text based on a customer s membership category lt c choose gt lt c iwhen test customer category trial gt lt c when gt lt c when test customer category member gt lt c when gt lt c iwhen test customer category preferred gt lt c when gt lt c otherwise gt lt c otherwise gt lt c choose gt FLOW CONTROL TAGS The choose when and otherwise tags can be used to construct an if then else statement as follows lt c choose gt lt c when test count Q gt No records matched your selection lt c when gt lt c otherwise gt lt c out value count gt records matched your selection lt c otherwise gt lt c choose gt Iterator lags The forEach tag allows you to iterate over a collection of objects You specify the collection via the items attribute and the current item is available through a scope variable named by the item attribute A large number of collection types are supported by forEach including all implementations of java util Collection and java util Map If the items attribute is of type java util Map then
324. ions Java Beans component which is a list of the suborders comprising an order and the ship dates of each suborder J avaBeans Components RetailPric eList RetailPriceList is a list of retail price items A retail price item contains a cof fee name a wholesale price per pound a retail price per pound and a distributor This data is used for two purposes it contains the price list presented to the end user and is used by CheckoutFormBean when it constructs the suborders dis patched to coffee distributors It first performs a JAXR lookup to determine the JAX RPC service endpoints It then queries each JAX RPC service for a coffee price list Finally it queries the JAXM service for a price list The two price lists are combined and a retail price per pound is determined by adding a 35 markup to the wholesale prices Disc overing the J AX RPC Service Instantiated by RetailPriceList JAXRQueryByName connects to the registry server and searches for coffee distributors registered with the name JAXRPCCof feeDistributor in the executeQuery method The method returns a collection of organizations which contain services Each service is accessible via a service binding or URI RetailPriceList makes a JAX RPC call to each URI ShoppingC artitem ShoppingCart is a list of shopping cart items A shopping cart item contains a retail price item the number of pounds of that item and the total price for that item OrderC onfimation OrderCo
325. ip you can conceive of The bad news is that it takes a lot of work to implement and it takes a bit of learning to use Most of the alternatives provide for simpler structure definitions while incorporating the XML Schema datatype standard For more information on the XML Schema see the W3C specs XML Schema Structures and XML Schema Datatypes as well as other information accessi ble at http www w3c org XML Schema RELAX NG Regular Language description for XML Simpler than XML Structure Schema is an emerging standard under the aus pices of OASIS Organization for the Advancement of Structured Information Systems RELAX NG use regular expression patterns to express constraints on structure relationships and it is designed to work with the XML Schema datatyping mechanism to express content constraints This standard also uses XML syntax and it includes a DTD to RELAX converter NG stands for Next Generation It s a newer version of the RELAX schema mechanism that integrates TREX For more information on RELAX NG see http www oasis open org com mittees relax ng TREX Tree Regular Expressions for XML A means of expressing validation criteria by describing a pattern for the struc ture and content of an XML document Now part of the RELAX NG specifica tion 193 194 UNDERSTANDING XML For more information on TREX see http www thai opensource com trex SOX Schema for Object oriented X
326. istener classes and register them in a way analogous to listeners defined at the WAR level Unlike WAR level listeners the order in which the tag library listeners are registered is undefined The only subelement of the listener element is the listener class element which must contain the fully qualified name of the listener class Since the IDE does not have a listener property on the customizer you must manually add the listener element to the TLD as follows 1 Right click the TLD 2 Choose open 3 Uncomment the listener element at the bottom of the TLD 4 Replace the dummy listener class with your listener class 123 124 CUSTOM TAGS IN JSP PAGES Tag Properties Each tag in the library is described by giving its name and the class of its tag handler information on the scripting variables created by the tag and informa tion on the tag s attributes Scripting variable information can be given directly in the TLD or through a tag extra info class see Tags That Define Scripting Variables page 121 Each attribute declaration contains an indication of whether the attribute is required whether its value can be determined by request time expressions and the type of the attribute see Tag Attribute Properties page 128 Tag properties are listed in Table 5 2 Table 5 2 Tag Properties Name The unique tag name Tag Class The fully qualified name of the tag handler class Display Name Optional name intended to
327. istrators of the Coffee Break Server it is a protected Web resource In order to load the price list a user must authenti cate using basic authentication and the authenticated user must be in the admin role DEPLOYING AND RUNNING THE APPLICATION To view the security settings for cbservice 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples cb cbservice 2 Expand the WEB INF directory 3 Select the web xm1 file 4 Select the Security property sheet You will notice that the login configu ration is specified to be BASIC a security role admin is defined and a secu rity constraint allows the admin role to access the resources in the WRCol lection If you edit WRCol lection you will notice that it contains the URL loadPriceList Deploying and Running the Application The source code for the Coffee Break application is located in the directory lt INSTALL gt j2eetutorial examples cb Within the cb directory are subdirec tories for each Web application jaxm jaxrpc cbservice Add Web services JARs to the compilation classpath To do so Choose Options from the Tools menu Expand the Building node then the Compiler Types node Choose External Compilation Select the Expert tab Click the Class Path property and open the property editor Click Add JAR Zip In the file chooser navigate to the lt S1AS7_HOME gt share 1lib directory and choose the jaxr api jar and saaj api ja
328. it and inserting it into the out object you must use a scriptlet lt Object o beanName getPropName gt Note the differences between the expression and the scriptlet the expression has an after the opening and does not terminate with a semicolon as does the scriptlet 110 JAVASERVER PAGES TECHNOLOGY The Duke s Bookstore application demonstrates how to use both forms to retrieve the formatted currency from the currency bean and insert it into the page For example bookstore3 web showcart jsp uses the form lt jsp getProperty name Ccurrency property format gt whereas bookstore2 web showcart jsp uses the form lt Currency getFormat gt The Duke s Bookstore application page bookstore2 web showcart jsp uses the following scriptlet to retrieve the number of books from the shopping cart bean and open a conditional insertion of text into the output stream lt Print a summary of the shopping cart int num cart getNumberOfiItems if num gt 0 gt Although scriptlets are very useful for dynamic processing using custom tags see Custom Tags in JSP Pages page 113 to access object properties and per form flow control is considered to be a better approach For example bookstore3 web showcart jsp replaces the scriptlet with the following cus tom tags lt bean define id num name cart property numberOfItems gt lt logic greaterThan name num value 0 gt Figure 4 4 summ
329. it is possible to pass a given piece of data as an attribute of the tag or as the tag s body Generally speaking any data that is a simple string or can be generated by evaluating a simple expression is best passed as an attribute Tags That Define Scripting Vanables A custom tag can define a variable that can be used in scripts within a page The following example illustrates how to define and use a scripting variable that con tains an object returned from a JNDI lookup Examples of such objects include enterprise beans transactions databases environment entries and so on lt tt lookup id tx type UserTransaction name java comp UserTransaction gt lt tx beginQ gt In the Duke s Bookstore application several pages use bean oriented tags from Struts to define scripting variables For example bookdetails jsp uses the bean parameter tag to create the bookId scripting variable and set it to the value of the bookId request parameter The jsp setProperty statement also sets the bookId property of the bookDB object to the value of the bookId request parameter The bean define tag retrieves the value of the bookstore database property bookDetails and defines the result as the scripting variable book lt bean parameter id bookId name bookId gt lt jsp setProperty name bookDB property bookId gt lt bean define id book name bookDB property bookDetai ls type database BookDetails gt lt h2 gt lt jsp g
330. its location which can be useful when there are multiple attachments When a SOAPMessage object has one or more AttachmentPart objects its SOAPPart object may or may not contain message content Another way to look at SOAP messaging is from the perspective of whether or not a messaging provider is used which is discussed at the end of the section Messaging Providers page 298 CONNECTIONS SOAPFault H any MIME headers Figure 10 2 SOAPMessage Object with Two AttachmentPart Objects Connections All SOAP messages are sent and received over a connection The connection can go directly to a particular destination or to a messaging provider A messaging provider is a service that handles the transmission and routing of messages and provides features not available when you use a connection that goes directly to its ultimate destination Messaging providers are explained in more detail later 295 296 WEB SERVICES MESSAGING WITH JAXM The JAXM API supplies the following class and interface to represent these two kinds of connections e javax xml soap SOAPConnection a connection from the sender directly to the receiver a point to point connection e javax xml messaging ProviderConnection a connection to a mes saging provider SOAPC onnec tion A SOAPConnection object which represents a point to point connection is sim ple to create and use One reason is that you do not have to do any configuration to use
331. ity on top of SOAP Note The ebXML Message Service Specification is available from http www oasis open org committees ebxml msg Among other things it provides a more secure means of sending business messages over the Internet than the SOAP specifications do Typically a business uses a messaging provider service which does the behind the scenes work required to transport and route messages When a messaging provider is used all JAXM messages go through it so when a business sends a message the message first goes to the sender s messaging provider then to the recipient s messaging provider and finally to the intended recipient It is also possible to route a message to go to intermediate recipients before it goes to the ultimate destination Because messages go through it a messaging provider can take care of house keeping details like assigning message identifiers storing messages and keeping track of whether a message has been delivered before A messaging provider can also try resending a message that did not reach its destination on the first attempt at delivery The beauty of a messaging provider is that the client using JAXM technology JAXM client is totally unaware of what the provider is doing in the background The JAXM client simply makes Java method calls and the mes saging provider in conjunction with the messaging infrastructure makes every thing happen behind the scenes JAXM Though in the ty
332. ixed content model which allows item elements to be interspersed in text is about as good as we can do In addition to the limitations of the mixed content model mentioned above there is no way to further qualify the kind of text that can occur where PCDATA has 213 214 UNDERSTANDING XML been specified Should it contain only numbers Should be in a date format or possibly a monetary format There is no way to say in the context of a DTD Finally note that the DTD offers no sense of hierarchy The definition for the title element applies equally to a slide title and to an item title When we expand the DTD to allow HTML style markup in addition to plain text it would make sense to restrict the size of an item title compared to a slide title for example But the only way to do that would be to give one of them a different name such as item title The bottom line is that the lack of hierarchy in the DTD forces you to introduce a hyphenation hierarchy or its equivalent in your namespace All of these limitations are fundamental motivations behind the development of schema specification standards Special Element Values in the DTD Rather than specifying a parenthesized list of elements the element definition could use one of two special values ANY or EMPTY The ANY specification says that the element may contain any other defined element or PCDATA Such a spec ification is usually used for the root element of a gener
333. k the client program and choose Execute The detailed steps follow 1 In the Explorer make sure that the MyHelloService WSDL resides in the hel loservice package In a previous section Creating MyHelloService page 274 the IDE gen erated the WSDL file Later in this section the IDE reads the WSDL file for information it needs to create runtime classes for the client STATIC STUB CLIENT EXAMPLE 279 2 Right click the staticstub package and choose File New Web Ser vices Web Service Client The Web Service Client pane of the New wizard appears 3 In the wizard s Specify Web Service Client pane do the following a In the Name field enter MyStatic b In the Package field enter staticstub c For the Create From buttons choose Local WSDL File d Click Next 4 In the wizard s Select Local WSDL File pane choose the MyHel1loSer vice WSDL of the hel loservice package 5 Click Finish The MyStatic client node appears in the Explorer 6 In Explorer right click the MyStatic client node and choose Generate Cli ent Proxy This action creates the MyStatic Documents and MyStaticGenClient packages This example will not use the MyStatic Document package which contains JSP pages for testing the service The MyStaticGenClient package contains the stub class serializer classes and other helper classes required by the client at runtime This package also contains the MyHel 1oServiceRPC and MyHelloService_Imp1 classes
334. ks journals magazines and the like using XML SMIL Synchronized Multimedia Integration Language SMIL is a W3C recommendation that covers audio video and animations It also addresses the difficult issue of synchronizing the playback of such elements For more information on SMIL see http www w3 org TR REC smi 1 MathML Mathematical Markup Language MathML is a W3C recommendation that deals with the representation of mathe matical formulas For more information on MathML see http www w3 org TR REC MathML SVG Scalable Vector Graphics SVG is a W3C working draft that covers the representation of vector graphic images Vector graphic images that are built from commands that say things like draw a line square circle from point xi to point m n rather than encoding the image as a series of bits Such images are more easily scalable although they typically require more processing time to render For more information on SVG see http www w3 org TR WD SVG 197 198 UNDERSTANDING XML DrawML Drawing Meta Language DrawML is a W3C note that covers 2D images for technical illustrations It also addresses the problem of updating and refining such images For more information on DrawML see http ww w3 org TR NOTE drawm eCommerce Slandards These standards are aimed at using XML in the world of business to business B2B and business to consumer B2C commerce ICE Information and Content
335. le making changes to the section is unlikely to make any of the documents that depend on it come out wrong Small inline substi tutions can be more problematic though For example if productName is defined as an entity the name change can be to a different part of speech and that can pro duce Suppose the product name is something like HtmlEdit That s a verb So you write a sentence that becomes You can HtmlEdit your file after the entity substitution occurs That sentence reads fine because the verb fits well in that con text But if the name is eventually changed to HtmlEditor the sentence becomes You can HtmlEditor your file which clearly doesn t work Still even if such simple substitutions can sometimes get you in trouble they can potentially save a lot of time One alternative would be to set up entities named productNoun pro ductVerb productAdj and productAdverb Normalizing DTDs Just as you can normalize your XML document you can also normalize your DTD declarations by factoring out common pieces and referencing them with a parameter entity Factoring out the DTDs also known as modularizing or nor malizing gives the same advantages and disadvantages as normalized XML easier to change somewhat more difficult to follow You can also set up conditionalized DTDs If the number and size of the condi tional sections is small relative to the size of the DTD as a whole that can le
336. les Reusable modules make it possible to divide the application development and deployment process into distinct roles so that different people or companies can perform different parts of the process The first two roles involve purchasing and installing the J2EE product and tools Once software is purchased and installed J2EE components can be developed by J2EE PRODUCT PROVIDER application component providers assembled by application assemblers and deployed by application deployers In a large organization each of these roles might be executed by different individuals or teams This division of labor works because each of the earlier roles outputs a portable file that is the input for a sub sequent role For example in the application component development phase an enterprise bean software developer delivers EJB JAR files In the application assembly role another developer combines these EJB JAR files into a J2EE application and saves it in an EAR file In the application deployment role a sys tem administrator at the customer site uses the EAR file to install the J2EE appli cation into a J2EE server The different roles are not always executed by different people If you work for a small company for example or if you are prototyping a sample application you might perform the tasks in every phase J 2EE Product Provider The J2EE product provider is the company that designs and makes available for purchase the J2EE platform A
337. line URL http uddi ibm com testregistry inquiryapi URL http localhost 8089 registry server RegistryServerServlet http proxyHost http proxyPort 8080 The default URL is the IBM test registry If you wish change the value of URL to another registry location To use the Sun ONE Studio UDDI Server Registry comment out the IBM registry and remove the comment charac ter from the second line 3 After http proxyHost insert the hostname and domain of your proxy server if you access the Internet from behind a firewall The format is usu ally myhost mydomain 4 If necessary change the value http proxyPort to one appropriate for your location 8080 is the usual port number 5 Save and close the file 334 WEB SERVICES MESSAGING WITH JAXM If you will be using the Sun ONE Studio UDDI Server Registry start the registry if you have not already done so 1 Select the Runtime tab of the Explorer 2 Expand the UDDI Server Registry node 3 Right click the Internal UDDI Registry node and choose the Start Server menu item Compiling and Running UddiPing To run the program you need to specify two command line arguments the uddi properties file and the name of the business for which you want to get a description Make sure you have followed the instructions in Setting the Classpath page 324 To compile and run UddiPing perform the following steps 1 Click the UddiPing file in the Filesystems tab 2 In the pr
338. line and links between two existing documents that are defined in a third Easily Processed As mentioned earlier regular and consistent notation makes it easier to build a program to process XML data For example in HTML a lt dt gt tag can be delim ited by lt dt gt another lt dt gt lt dd gt or lt d1 gt That makes for some difficult pro gramming But in XML the lt dt gt tag must always have a lt dt gt terminator or else it will be defined as a lt dt gt tag That restriction is a critical part of the con straints that make an XML document well formed Otherwise the XML parser won t be able to read the data And since XML is a vendor neutral standard you can choose among several XML parsers any one of which takes the work out of processing XML data Hierarchical Finally XML documents benefit from their hierarchical structure Hierarchical document structures are in general faster to access because you can drill down to the part you need like stepping through a table of contents They are also eas ier to rearrange because each piece is delimited In a document for example you could move a heading to a new location and drag everything under it along with the heading instead of having to page down to make a selection cut and then paste the selection into a new location How CAN You USE XML How Can You Use XML There are several basic ways to make use of XML e Traditional data processing whe
339. lined JSP elements These elements are discussed in JavaBeans Components in JSP Pages page 103 You can also create a JavaBeans component in a decla ration or scriptlet and invoke the methods of a JavaBeans component in a scriptlet or expression Declarations scriptlets and expressions are described in JSP Scripting Elements page 95 Shared Objects The conditions affecting concurrent access to shared objects described in Con trolling Concurrent Access to Shared Resources page 56 apply to objects accessed from JSP pages that run as multithreaded servlets You can indicate how a Web container should dispatch multiple client requests with the following page directive lt page isThreadSafe true false gt When isThreadSafe is set to true the Web container may choose to dispatch multiple concurrent client requests to the JSP page This is the default setting If using true you must ensure that you properly synchronize access to any shared objects defined at the page level This includes objects created within declara tions JavaBeans components with page scope and attributes of the page scope object If isThreadSafe is set to false requests are dispatched one at a time in the order they were received and access to page level objects does not have to be controlled However you still must ensure that access to attributes of the app1i cation or session scope objects and to JavaBeans components with application or session
340. llection orgs response getCollection You can also use classifications to find organizations that offer services based on technical specifications that take the form of WSDL Web Services Description Language documents In JAXR a concept is used as a proxy to hold the infor mation about a specification The steps are a little more complicated than in the previous example because the client must find the specification concepts first then the organizations that use those concepts QUERYING A REGISTRY 359 The following code fragment finds all the WSDL specification instances used within a given registry You can see that the code is similar to the NAICS query code except that it ends with a call to findConcepts instead of findOrganiza tions String schemeName uddi org types ClassificationScheme uddiOrgTypes bqm findClassificationSchemeByName null schemeName Create a classification specifying the scheme and the taxonomy name and value defined for WSDL documents by the UDDI specification Classification wsdlSpecClassification blcm createClassification uddiOrgTypes wsdlSpec wsdlSpec Collection classifications new ArrayList classifications add wsd1SpecClassi fication Find concepts BulkResponse br bqm findConcepts null null classifications null null To narrow the search you could use other arguments of the findConcepts method search qualifiers names external iden
341. lmost identical to the sample program JAXRDelete java which is described in Removing Data from the Registry page 365 The makeConnection method is identical to the JAXRPublisher method of the same name The createOrgKey method is a utility method that takes one argument the string value extracted from the key file It obtains the RegistryService object and the BusinessLifeCycleManager object then creates a Key object from the string value The executeRemove method takes three arguments a username a password and the Key object returned by the createOrgKey method It uses the username and password arguments to establish its security credentials with the Registry Server just as the executePublish method does JAXM DISTRIBUTOR SERVICE 393 The method then wraps the Key object in a Collection and uses the Business LifeCycleManager object s deleteOrganizations method to delete the organi zation Collection keys new ArrayListQ keys add key BulkResponse response blcm deleteOrganizations keys The deleteOrganizations method returns the keys of the organizations it deleted so the executeRemove method then verifies that the correct operation was performed and displays the key for the deleted organization Collection retKeys response getCollection Iterator keyIter retKeys iterator javax xml registry infomodel Key orgKey null if keyIter hasNextQ orgKey javax xml registry infomodel Key keyIter nextQ
342. ls lists is strictly prohibited DOCUMENTATION IS PROVIDED AS IS AND ALL EXPRESS OR IMPLIED CONDITIONS REPRESENTATIONS AND WARRANTIES INCLUDING ANY IMPLIED WARRANTY OF MER CHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE DISCLAIMED EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID Copyright 2003 Sun Microsystems Inc 4150 Network Circle Santa Clara California 95054 Etats Unis Tous droits r serv s Droits du gouvernement am ricain utlisateurs gouvernmentaux logiciel commercial Les utilisateurs gouvernmentaux sont soumis au contrat de licence standard de Sun Micro systems Inc ainsi qu aux dispositions en vigueur de la FAR Federal Acquisition Regulations et des suppl ments a celles ci Cette distribution peut comprendre des composants d velopp s pardes tierces parties Sun Sun Microsystems le logo Sun Java JavaServer Pages Enterprise JavaBeans Java Naming and Directory Interface EJB JSP J2ZEE J2SE et le logo Java Coffee Cup sont des marques de fabrique ou des marques d pos es de Sun Microsystems Inc aux Etats Unis et dans d autres pays A moins qu autrement autoris le code de logiciel en tous les mat riaux techniques dans le pr sent arti cles y compris FAQs chantillons est fourni sous ce permis Les produits qui font l objet de ce manuel d entretien et les informations qu il contient sont r gis par la l gislation am ricaine en m
343. m the RegistryService object If it is using the registry for simple queries only it may need to obtain only a BusinessQue ryManager object Querying a Registry The simplest way for a client to use a registry is to query it for information about the organizations that have submitted data to it The BusinessQueryManager interface supports a number of find methods that allow clients to search for data using the JAXR information model Many of these methods return a BulkRe sponse a collection of objects that meets a set of criteria specified in the method arguments The most useful of these methods are e findOrganizations which returns a list of organizations that meet the specified criteria often a name pattern or a classification within a classi fication scheme e findServices which returns a set of services offered by a specified orga nization e findServiceBindings which returns the service bindings information about how to access the service that are supported by a specified service The JAXRQuery program illustrates how to query a registry by organization name and display the data returned The JAXRQueryByNAICSClassification and JAXRQueryByWSDLClassification programs illustrate how to query a registry QUERYING A REGISTRY using classifications All JAXR providers support at least the following taxono mies for classifications e The North American Industry Classification System NAICS See http www census gov epcd w
344. maps parameter names to a String of all val ues for that parameter obtained by calling ServletRequest getParame terValues String header a Map that maps header names to a single String header value obtained by calling ServletRequest getheader String headerValues a Map that maps header names to a String of all values for that parameter obtained by calling ServletRequest getHead ers String cookie a Map that maps cookie names to a single Cookie obtained by calling HttpServletRequest getCookie String initParam a Map that maps a parameter names to a single String param eter value obtained by calling ServletRequest getInitParame ter String When an expression references one of these objects by name the appropriate object is returned instead of the corresponding attribute For example page Context returns the PageContext object even if there is an existing pageCon JSTL EXPRESSION LANGUAGE 157 text attribute containing some other value Table 6 2 shows some examples of using these implicit objects Table 6 2 Example JSTL Expressions The context path obtained from HttpServ pageContext request contextPath ieekequiest The numberOfItems property of the ses sessionScope cart numberOfItems t p sion scoped attribute named cart The String value of the mycom productId parameter param mycom productId Literals e Boolean true and false e Long as in Java e Floatin
345. me inventory property quantity value lt Integer bookRow 7 gt gt lt c if test item quantity gt inventory quantity gt lt c set var sufficientInventory value false gt lt h3 gt lt font color red size 2 gt lt fmt message key OrderError gt There is insufficient inventory for lt i gt lt c out value bookRow 3 gt lt i gt lt font gt lt h3 gt lt c if gt 173 174 JAVASERVER PAGES STANDARD TAG LIBRARY lt c forEach gt lt c forEach gt lt c if test sufficientInventory true gt lt c forEach var item items sessionScope cart items gt lt c set var book value item item gt lt c set var bookId value book bookId gt lt sql query var books sql select from PUBLIC books where id gt lt sql param value bookId gt lt sql query gt lt c forEach var bookRow begin 0 items books rows gt lt sql update var books sql update PUBLIC books set inventory inventory where id gt lt sql param value item quantity gt lt sql param value bookId gt lt sql update gt lt c forEach gt lt c forEach gt lt h3 gt lt fmt message key ThankYou gt lt c out value param cardname gt lt h3 gt lt br gt lt c if gt lt sql transaction gt query Tag Result Interface The Result interface is used to retrieve information from objects returned from a query tag public inte
346. ment createElement name Text tnNode document createTextNode Kona newNameNode appendChi 1d tnNode Node newPriceNode document createElement price Text tpNode document createTextNode 13 50 newPriceNode appendChi Id tpNode newCoffeeNode appendChi 1d CnewNameNode newCoffeeNode appendChi 1d newPriceNode rootNode insertBefore newCoffeeNode thisCoffeeNode break Note that this code fragment is a simplification in that it assumes that none of the nodes it accesses will be a comment an attribute or ignorable white space You get a DOM parser that is validating the same way you get a SAX parser that is validating You call setValidating true on a DOM parser factory before THE XSLT API using it to create your DOM parser and you make sure that the XML document being parsed refers to its schema in the DOCTYPE declaration XML Namespaces All the names in a schema which includes those in a DTD are unique thus avoiding ambiguity However if a particular XML document references multiple schemas there is a possibility that two or more of them contain the same name Therefore the document needs to specify a namespace for each schema so that the parser knows which definition to use when it is parsing an instance of a par ticular schema There is a standard notation for declaring an XML Namespace which is usually done in the root element of an XML document In the following namespace dec laratio
347. ment which is entirely different from the title element defined in the slideshow DTD Because there is no hierarchy in the DTD these two definitions conflict Note The Modularized XHTML DTD also defines a title element that is intended to be the document title so we can t avoid the conflict by changing xhtml dtd the problem would only come back to haunt us later You could use XML namespaces to resolve the conflict You ll take a look at that approach in the next section Alternatively you could use one of the more hierar chical schema proposals described in Schema Standards page 192 The sim RESOLVING A NAMING CONFLICT 229 plest way to solve the problem for now though is simply to rename the title element in slideshow dtd Note The XML shown here is contained in slideshow3 dtd and slideSample09 xml which references copyright xm l and xhtm1l dtd The browsable versions are s1ideshow3 dtd htm1 slideSamp1eQ9 xm1 html copy right xm1 htm1 and xhtm1 dtd htm1 To keep the two title elements separate you ll create a hyphenation hierarchy Make the changes highlighted below to change the name of the title element in slideshow dtd to slide title lt ELEMENT slide Cimage slide title item gt lt ATTLIST slide type tech exec all IMPLIED gt lt Defines the inline declaration gt lt ENTITY xhtml SYSTEM xhtml dtd gt xhtml lt ELEMENT slide title inline gt
348. mpleGreeter 4 Right click SimpleGreeter and choose Open The Source Editor displays SimpleGreeter java which has two meth ods sayHello and sayGoodbye In a later step you will assign these methods to MyHelloService At runtime the service s remote clients will be able to invoke these methods 5 Right click the Source Editor and choose Compile 6 Close the Output window and the Source Editor 7 Right click the helloservice package and choose New gt Web Service s Web Service The Web Service pane of the New wizard appears 8 In the wizard s Specify Web Service pane do the following a In the Name field enter MyHelloService b In the Package field enter hel loservice c For the Create From buttons choose Java Methods d For the Architecture buttons choose Web centric e Click Next 9 In the wizard s Select Methods pane do the following a Expand the nodes in the hel loservice package until you see the meth ods beneath the SimpleGreeter class b Choose the sayHello and sayGoodbye methods c Click Finish SPECIFYING THE SOAP RPC URL 275 In the Explorer a Web service node a blue sphere in a cube for MyHel1oSer vice appears Specifying the SOAP RPC URL 1 Right click the MyHe11oService node choose Properties and examine the SOAP RPC URL property This URL is sometimes called the service endpoint address Remote cli ents of the service use this URL to locate the service In a later step
349. n the notation xmIns identifies nsName as a namespace and nsName is set to the URL of the actual namespace lt priceList xmlns nsName myDTD dtd xmIns otherNsName myOtherDTD dtd gt lt priceList gt Within the document you can specify which namespace an element belongs to as follows lt nsName price gt To make your SAX or DOM parser able to recognize namespaces you call the method setNamespaceAware true on your ParserFactory instance After this method call any parser that the parser factory creates will be namespace aware The XSLT API XML Stylesheet Language for Transformations XSLT defined by the W3C XSL Working Group describes a language for transforming XML documents into other XML documents or into other formats To perform the transformation you usually need to supply a style sheet which is written in the XML Stylesheet Language XSL The XSL style sheet specifies how the XML data will be dis played and XSLT uses the formatting instructions in the style sheet to perform the transformation 247 248 INTRODUCTION TO WEB SERVICES JAXP supports XSLT with the javax xm1 transform package which allows you to plug in an XSLT transformer to perform transformations The subpackages have SAX DOM and stream specific APIs that allow you to perform transfor mations directly from DOM trees and SAX events The following two examples illustrate how to create an XML document from a DOM tree and how to tra
350. n JavaBeans components and performing request dispatching simplify JSP page development and mainte nance JSP technology also provides a mechanism for encapsulating other types of dynamic functionality in custom tags which are extensions to the JSP lan guage Custom tags are usually distributed in the form of a tag library which defines a set of related custom tags and contains the objects that implement the tags Some examples of tasks that can be performed by custom tags include operations on implicit objects processing forms accessing databases and other enterprise services such as e mail and directories and performing flow control JSP tag libraries are created by developers who are proficient at the Java programming language and expert in accessing data and other services and are used by Web application designers who can focus on presentation issues rather than being concerned with how to access enterprise services As well as encouraging divi sion of labor between library developers and library users custom tags increase productivity by encapsulating recurring tasks so that they can be reused across more than one application 113 114 CUSTOM TAGS IN JSP PAGES Tag libraries are receiving a great deal of attention in the JSP technology com munity For more information about tag libraries and for pointers to some freely available libraries see http java sun com products jsp taglibraries html What Is a Custom Tag A cu
351. n as FIRSTNAME LASTNAME and EMAIL an RDF description could make it possible to transfer data to an application that wanted NAME and EMAILADDRESS Just think One day you may not need to type your name and address at every Web site you visit For the latest information on RDF see http ww w3 org TR REC rdf syn tax RDF Schema RDF Schema allows the specification of consistency rules and additional infor mation that describe how the statements in a Resource Description Framework RDF should be interpreted For more information on the RDF Schema recommendation see http www w3 org TR rdf schema X XML Topic Maps In many ways a simpler more readily usable knowledge representation than RDF the topic maps standard is one worth watching So far RDF is the W3C standard for knowledge representation but topic maps could possibly become the developer s choice among knowledge representation standards STANDARDS THAT BUILD ON XML For more information on XML Topic Maps http ww topic maps org xtm index htm1 For information on topic maps and the Web see http www topicmaps org Standards That Build on XML The following standards and proposals build on XML Since XML is basically a language definition tool these specifications use it to define standardized lan guages for specialized purposes Extended Document Standards These standards define mechanisms for producing extremely complex docu ments boo
352. n instance of SOAPConnectionFactory and uses it to create a connection Then it gets an instance of MessageFactory and uses it to create a message SOAPConnectionFactory scf SOAPConnectionFactory newInstance SOAPConnection connection scf createConnection MessageFactory msgFactory MessageFactory newInstance SOAPMessage msg msgFactory createMessage The new SOAPMessage object msg automatically contains a SOAPPart object that contains a SOAPEnvelope object The SOAPEnvelope object contains a SOAPBody object which is the element you want to access in order to add content to it The next lines of code get the SOAPPart object the SOAPEnvelope object and the SOAPBody object SOAPEnvelope envelope msg getSOAPPart getEnvelope SOAPBody body envelope getBody The following lines of code add an element with a fully qualified name and then add two attributes to the new element The first attribute has the name generic and the value 1 0 The second attribute has the name maxRows and the value 100 Then the code adds a child element with the name name and 329 330 WEB SERVICES MESSAGING WITH JAXM adds some text to it with the method addTextNode The text added is the busi ness name you will supply when you run the application SOAPBodyElement findBusiness body addBodyE1ement envelope createName find_business urn uddi org api findBusiness addAttribute envelope createName
353. n of JAXM messages For more information about messaging providers see Messaging Providers page 298 The Provider Administration tool is normally used by System Administrators but others may use it as well Exploring this tool gives you more of an idea of what a messaging provider needs to know For example a messaging provider maintains a list of the endpoints to which you can send messages You can add a new endpoint to this list using the Provider Administration tool If a message is not delivered successfully on the first try a messaging provider will continue attempting to deliver it You can specify the number of times the messaging pro vider should attempt delivery by supplying a retry limit Setting this limit is another thing you can do with the Provider Administration tool The following lists the ways you can use the tool to set a messaging provider s properties e To add modify or delete an endpoint e To change the number of retries the number of times the provider will try to send a message e To change the retry interval the amount of time the provider will wait before trying to send a message again e To change the directory where the provider logs messages e To set the number of messages per log file Conclusion JAXM provides a Java API that simplifies writing and sending XML messages You have seen how to use this API to write client code for JAXM request response messages and one way messages You have al
354. n the order in which fil ter mappings appear in the filter mapping list of a WAR You specify a filter mapping list for a Web module by e Declaring the filter using the Filters property This property creates a name for the filter and declares the filter s implementation class and initialization parameters e Mapping the filter to a Web resource in a Filter Mappings property This property maps a filter name to a Web resource by name or by URL pattern To add a filter and filter mapping properties in the IDE Mount the Web module as a filesystem Expand the WEB INF node Select the web xml file Select the Deployment tab in the property editor Select the Filters property and open the property editor Click Add Type the filter name and filter class Select the Filter Mappings property and to open the property editor Select the filter 10 Click Add 11 Type a URL pattern or servlet name to which the filter should be applied 12 Click OK twice For an example filter definition and mapping see The Example Servlets page 48 O AN DN FW WN If you want to log every request to a Web application you would map the hit counter filter to the URL pattern Table 3 6 summarizes the filter mapping list SPECIFYING FILTER MAPPINGS for the Duke s Bookstore application The filters are matched by URL pattern and each filter chain contains only one filter Table 3 6 Duke s Bookstore Filter Mapping
355. nables Tag Handlers A tag handler is responsible for creating and setting the object referred to by the scripting variable into a context accessible from the page It does this by using the pageContext setAttribute name value scope or pageCon text setAttribute name value methods Typically an attribute passed to the custom tag specifies the name of the scripting variable object this name can be retrieved by invoking the attribute s get method described in Using Scope Objects page 55 If the value of the scripting variable is dependent on an object present in the tag handler s context it can retrieve the object using the pageContext getAt tribute name scope method The usual procedure is that the tag handler retrieves a scripting variable per forms some processing on the object and then sets the scripting variable s value using the pageContext setAttribute name object method The scope that an object can have is summarized in Table 5 4 The scope con strains the accessibility and lifetime of the object Table 5 4 Scope of Objects Accessible From Lifetime Until the response has been sent back Current page to the user or the request is passed to a new page Current page and any included or Until the response has been sent back forwarded pages to the user request Current request and any subsequent session request from the same browser The life of the user s session subject to session lifetime
356. nals tags for manipulating XML documents internationaliza tion and locale specific formatting tags and SQL tags It also introduces a new expression language to simplify page development and provides an 440 API for developers to simplify the configuration of JSTL tags and the devel opment of custom tags that conform to JSTL conventions JAXR client A client program that uses the JAXR API to access a business registry via a JAXR provider JAXR provider An implementation of the JAXR API that provides access to a specific regis try provider or to a class of registry providers that are based on a common specification JDBC An API for database independent connectivity to a wide range of data sources JNDI See Java Naming and Directory Interface JSP See JavaServer Pages JSP action A JSP element that can act on implicit objects and other server side objects or can define new scripting variables Actions follow the XML syntax for elements with a start tag a body and an end tag if the body is empty it can also use the empty tag syntax The tag must use a prefix JSP action custom An action described in a portable manner by a tag library descriptor and a collection of Java classes and imported into a JSP page by a taglib direc tive A custom action is invoked when a JSP page uses a custom tag JSP action standard An action that is defined in the JSP specification and is always available to a JSP file without being impo
357. nd if the information guides XML processing but is never seen by a user then it may be better to model it as an attribute For example in order entry data for shoes shoe size would definitely be an element On the other hand a manu facturer s code number would be reasonably modeled as an attribute Consumer Provider Another way of thinking about the visibility heuristic is to ask who is the consumer and or provider of the information The shoe size is entered by a human sales clerk so it s an element The manufacturer s code number for a given shoe model on the other hand may be wired into the application or stored in a database so that would be an attribute If it were entered by the clerk though it should perhaps be an element Container vs Contents Perhaps the best way of thinking about elements and attributes is to think of an element as a container To reason by analogy the contents of the con tainer water or milk correspond to XML data modeled as elements Such data is essentially variable On the other hand characteristics of the con tainer blue or white pitcher can be modeled as attributes That kind of information tends to be more immutable Good XML style will in some consistent way separate each container s contents from its characteristics To show these heuristics at work In a slideshow the type of the slide executive or technical is best modeled as an attribute It is a characteristic of the slide
358. nd string pairs in a resource bundle look like here are a few lines from the file mes sages BookMessages java TitleCashier Cashier TitleBookDescription Book Description Visitor You are visitor number What What We re Reading Talk talks about how Web components can transform the way you develop applications for the Web This is a must read for any self respecting Web developer Start Start Shopping ACCESSING DATABASES FROM WEB APPLICATIONS 39 To get the correct strings for a given user a Web component retrieves the locale set by a browser language preference from the request opens the resource bun dle for that locale and then saves the bundle as a session attribute see Associat ing Attributes with a Session page 76 ResourceBundle messages ResourceBundle session getAttributeC messages if messages null Locale locale request getLocale messages ResourceBundle getBundle WebMessages locale session setAttribute messages messages A Web component retrieves the resource bundle from the session ResourceBundle messages ResourceBundle session getAttribute messages and looks up the string associated with the key TitleCashier as follows messages getString TitleCashier This has been a very brief introduction to internationalizing Web applications For more information on this subject see the Java BluePrints http java sun
359. nding a request response message for a client that does not use a messaging provider Then we ll do a walkthrough of a client that uses a messaging provider sending a one way message Both types of client may add attachments to a message so adding attachments is covered as a separate topic Finally we ll see what SOAP faults are and how they work The section Code Examples page 323 puts the code fragments you will pro duce into runnable applications which you can test yourself The JAXM part of the case study JAXM Distributor Service page 393 demonstrates how JAXM code can be used in a Web service showing both the client and server code Client withouta Messaging Provider An application that does not use a messaging provider is limited to operating in a client role and can send only request response messages Though limited it can make use of Web services that are implemented to do request response messag ing Getting a SOAPC onnection Object The first thing any JAXM client needs to do is get a connection either a SOAP Connection object or a ProviderConnection object The overview section Connections page 295 discusses these two types of connections and how they are used A client that does not use a messaging provider has only one choice for creating a connection which is to create a SOAPConnection object This kind of connec CLIENT WITHOUT A MESSAGING PROVIDER tion is a point to point connection meaning that it goe
360. ndler Tags with Atinbutes Defining Attributes in a Tag Handler For each tag attribute you must define a property and get and set methods that conform to the JavaBeans architecture conventions in the tag handler For exam ple the tag handler for the Struts logic present tag lt logic present parameter Clear gt 128 CUSTOM TAGS IN JSP PAGES contains the following declaration and methods protected String parameter null public String getParameter return this parameter public void setParameter String parameter this parameter parameter A tag attribute whose value is a String can name an attribute of one of the implicit objects available to tag handlers An implicit object attribute would be accessed by passing the tag attribute value to the set get Attribute method of the implicit object This is a good way to pass scripting variable names to a tag handler where they are associated with objects stored in the page context See Implicit Objects page 92 Tag Atribute Properties For each tag attribute you must specify whether the attribute is required whether the value can be determined by an expression and optionally the type of the attribute For static values the type is always java lang String If the value can be determined at run time by an expression they you must also specify the return type expected from any expression If a tag attribute is not required a tag handler should provide a
361. ndling e HTML forms e Templates e JavaBeans components e Logic processing The Duke s Bookstore application uses tags from the Struts bean and logic sublibraries The template tag library defines a set of tags for creating an application template The template is a JSP page with placeholders for the parts that need to change with each screen Each of these placeholders is referred to as a parameter of the template For example a simple template could include a title parameter for the top of the generated screen and a body parameter to refer to a JSP page for the custom content of the screen The template is created with a set of nested tags definition screen and parameter that are used to build a table of screen definitions for Duke s Bookstore and with an insert tag to insert parameters from the table into the screen Figure 5 1 shows the flow of a request through the following Duke s Bookstore Web components e template jsp which determines the structure of each screen It uses the insert tag to compose a screen from subcomponents e screendefinitions jsp which defines the subcomponents used by each screen All screens have the same banner but different title and body con tent specified by the JSP Pages column in Table 4 1 e Dispatcher a servlet which processes requests and forwards to tem plate jsp 115 116 CUSTOM TAGS IN JSP PAGES Web Container Dispatcher MEET A Servlet HttpServlet Reques
362. ne can occur zero or more times in succession The result of this specifi cation is known as a mixed content model because any number of item elements can be interspersed with the text Such models must always be defined with PCDATA specified first some number of alternate items divided by vertical bars and an asterisk at the end Save a copy of this DTD as slideSamplela dtd for use when experimenting with basic DTD processing Limitations of DTDs It would be nice if we could specify that an item contains either text or text fol lowed by one or more list items But that kind of specification turns out to be hard to achieve in a DTD For example you might be tempted to define an item like this lt ELEMENT item PCDATA C PCDATA item gt That would certainly be accurate but as soon as the parser sees PCDATA and the vertical bar it requires the remaining definition to conform to the mixed con tent model This specification doesn t so you get can error that says I1legal mixed content model for item Found amp x28 where the hex char acter 28 is the angle bracket the ends the definition Trying to double define the item element doesn t work either A specification like this lt ELEMENT item PCDATA gt lt ELEMENT item PCDATA item gt produces a duplicate definition warning when the validating parser runs The second definition is in fact ignored So it seems that defining a m
363. ne principal authorizes another principal to use its identity or privileges with some restrictions deployment The process whereby software is installed into an operational environment deployment descriptor An XML file provided with each module and application that describes how they should be deployed The deployment descriptor directs a deployment tool to deploy a module or application with specific container options and describes specific configuration requirements that a deployer must resolve digest authentication An authentication mechanism in which a Web application authenticates to a Web server by sending the server a message digest along its HTTP request message The digest is computed by employing a one way hash algorithm to a concatenation of the HTTP request message and the client s password The digest is typically much smaller than the HTTP request and doesn t contain the password 434 distributed application An application made up of distinct components running in separate runtime environments usually on different platforms connected via a network Typi cal distributed applications are two tier client server three tier client middleware server and multitier client multiple middleware multiple servers document root The top level directory of a WAR The document root is where JSP pages client side classes and archives and static Web resources are stored DOM Document Object Model A tree of objects with
364. nent 3 Select the Deployment Entries property and open the property editor 4 Click Edit 5 Under the Init Parameters table click Add 32 INTRODUCTION TO WEB APPLICATIONS 6 Type the parameter name and value 7 Click OK twice Error Mappings You can specify a mapping between the status code returned in an HTTP response or a Java programming language exception returned by any Web com ponent and a Web resource see Handling Errors page 54 To set up the map ping you must specify the Error Pages property for the Web deployment descriptor To add an error mapping in the IDE Mount the Web module as a filesystem Expand the WEB INF node Select the web xml file Select the Deployment tab in the property editor Select the Error Pages property and open the property editor Click Add Add an HTTP Error Code see HTTP Responses page 428 or Java Exception Type a DAMA WN 8 Enter the name of a resource to be invoked when the status code or excep tion is returned in the Error Page Field The name should have a leading forward slash Note You can also define error pages for a JSP page contained in a Web module If error pages are defined for both the Web module and a JSP page the JSP page s error page takes precedence For an example error page mapping see The Example Servlets page 48 References to Environment Entries Resource Environment Entries or Resources If your Web components
365. nfirmations is a list of order confirmation objects An order confirma tion contains order and confirmation objects 412 THE COFFEE BREAK APPLICATION CheckoutfFomBean CheckoutFormBean checks the completeness of information entered into check outForm If the information is incomplete the bean populates error messages and Dispatcher redisplays checkoutForm with the error messages If the infor mation is complete order requests are constructed from the shopping cart and the information supplied to checkoutForm and are sent to each distributor As each confirmation is received an order confirmation is created and added to OrderConfirmations Note that since the JAX RPC client returns JavaBeans components defined in the clientutil package CheckoutFormBean converts types returned from the JAX RPC client to equivalent types defined in the cbservice package if all0k String orderId CCNumber cbconfirmation new ConfirmationBean cbconfirmation setOrderId orderlId AddressBean cbaddress new AddressBean cbaddress setStreet street cbaddress setCity city cbaddress setState state cbaddress setZip zip CustomerBean cbcustomer new CustomerBean cbcustomer setFirstName firstName cbcustomer setLastName lastName cbcustomer setPhoneNumber areaCode phoneNumber cbcustomer setEmai lAddress email for Iterator d rpl getDistributors iterator d hasNextQ String distributor String
366. ng access to resources in a system Java WSDP requires three types of authentication basic form based and mutual and supports digest authentication authorization The process by which access to a method or resource is determined Autho rization depends upon the determination of whether the principal associated with a request through authentication is in a given security role A security role is a logical grouping of users defined by the person who assembles the application A deployer maps security roles to security identities Security identities may be principals or groups in the operational environment authorization constraint An authorization rule that determines who is permitted to access a Web resource collection ABCDEFGHIJKLMNOPQRSTUVWXYZ B2B Business to business basic authentication An authentication mechanism in which a Web server authenticates an entity with a user name and password obtained using the Web application s built in authentication mechanism binary entity See unparsed entity binding Construction of the code needed to process a well defined bit of XML data build file The XML file that contains one project that contains one or more targets A target is a set of tasks you want to be executed When starting Ant you can select which target s you want to have executed When no target is given the project s default is used build properties file A file named build properties that contains propertie
367. ng carts and so on Often these classes conform to the JavaBeans component architecture e Client side classes applets and utility classes The top level directory of a Web module is the document root of the application The document root is where JSP pages client side classes and archives and static Web resources are stored The document root contains a subdirectory called WEB INF which contains the following files and directories e web xml The Web application deployment descriptor e Tag library descriptor files see Tag Library Descriptors page 122 e classes A directory that contains server side classes servlets utility classes and JavaBeans components e lib A directory that contains JAR archives of libraries called by server side classes You can also create application specific subdirectories that is package directo ries in either the document root or the WEB INF classes directory CREATING A WEB MODULE 29 Creating a Web Module When you develop Web applications using the IDE it creates the necessary Web module structure for you It also creates or modifies the Web application deploy ment descriptor based on information entered into wizards and property sheets To create a Web module in the IDE 1 Select File New This opens the new wizard 2 Scroll to the JSP amp Servlet node and expand it 3 Select Web module 4 Click Next 5 Type the path to the directory for the Web module 6 Click Fini
368. ng conventions of client locales This section describes tags that support the internationalization of JSP pages JSTL defines tags for e Setting the locale for a page e Creating locale sensitive messages 170 JAVASERVER PAGES STANDARD TAG LIBRARY e Formatting and parsing data elements such as numbers currencies dates and times in a locale sensitive or customized manner Table 6 6 Internationalization Tags Function Tags setLocale Setting Locale requestEncoding bundle message param setBundle Messaging formatNumber formatDate Number and Date parseDate Formatting parseNumber setTimeZone timeZone Setting the Locale The setLocale tag is used to override the client specified locale for a page The requestEncoding tag is used to set the request s character encoding in order to be able to correctly decode request parameter values whose encoding is different from ISO 8859 1 Messaging Tags By default browser sensing capabilities for locales are enabled This means that the client determines via its browser settings which locale to use and allows page authors to cater to the language preferences of their clients bundle Tag You use the bundle tag to specify a resource bundle for a page To define a resource bundle for a Web application you specify the context param eter javax servlet jsp jstl fmt localizationContext in the Web appli FORMATTING TAGS cation deployment descriptor H
369. ngs tab Click the Path Settings link Add lt S1STUDIO_HOME gt jwsdp common lib jaxm runtime jar to the Classpath Suffix text area Click Save 7 Click the General tab 8 Apply the changes then stop and restart the server nA BW N nN To deploy and run the JAXM Provider perform the following steps 1 Mount the following filesystem lt S1STUDIO_HOME gt jwsdp services jaxm provider If you click on the file WEB INF provider xm1 you may notice that it is marked as having invalid XML If you open this file in a text editor right click and choose Validate XML from the menu you will see an error message about a missing DTD file Ignore this error message 2 Specify the following context root for the web module jaxm provider 3 Right click the WEB INF node and choose Deploy from the menu 344 WEB SERVICES MESSAGING WITH JAXM The J AXM Provider Administrator The JAXM Provider Administrator is a simple web based administrative tool for the JAXM provider The source files for the JAXM Provider Administrator are not in the tutorial examples directory Instead they are in lt S1STUDIO_HOME gt jwsdp services To deploy and run the JAXM Provider Administrator perform the following steps 1 Mount the following filesystem lt S1STUDIO_HOME gt jwsdp services jaxm provideradmin If you click on the file WEB INF provider xm1 you may notice that it is marked as having invalid XML If you open this file in a tex
370. nkage between a service binding and a technical specification that describes how to use the ser vice using the service binding The following code fragment shows how to create a collection of services add service bindings to a service then add the services to the organization It speci fies an access URI but not a specification link Because the access URI is not real and because JAXR by default checks for the validity of any published URI the binding sets its validateURI property to false Create services and service Collection services new ArrayListQ Service service blcm createService My Service Name InternationalString is blcm createInternationalString My Service Description service setDescription is Create service bindings Collection serviceBindings new ArrayListQ ServiceBinding binding blcm createServiceBinding is blcm createInternationalString My Service Binding Description binding setDescription is allow us to publish a bogus URL without an error binding setValidateURI false binding setAccessURI http TheCoffeeBreak com 8080 sb serviceBindings add binding Add service bindings to service service addServiceBindings serviceBindings Add service to services then add services to organization services add service org addServices services Saving an Organization The primary method a client uses to add or modify organization data is the
371. ns form the resulting XML document into HTML using an XSL style sheet Transforming a DOM Tre to an XML Document To transform the DOM tree created in the previous section to an XML document the following code fragment first creates a Transformer object that will perform the transformation TransformerFactory transFactory TransformerFactory newInstanceQ Transformer transformer transFactory newTransformer Using the DOM tree root node the following line of code constructs a DOM Source object as the source of the transformation DOMSource source new DOMSource document The following code fragment creates a StreamResult object to take the results of the transformation and transforms the tree into an XML file File newXML new FileC newXML xm1 FileOutputStream os new FileOutputStream CnewXML StreamResult result new StreamResult os transformer transform source result Transforming an XML Document to an HIML Document You can also use XSLT to convert the new XML document newXML xm1 to HTML using a style sheet When writing a style sheet you use XML Namespaces to reference the XSL constructs For example each style sheet has a THE XSLT API 249 root element identifying the style sheet language as shown in the following line of code lt xslistylesheet version 1 0 xmlns xsl http www w3 org 1999 XSL Transform gt When referring to a particular construct in the style sheet language you u
372. nt and a URL object that contains the URL specifying the endpoint of the receiver SOAPMessage response soapConnection call message endpoint An application that is using a messaging provider uses the ProviderConnection method send to send a message This method sends the message asynchronously meaning that it sends the message and returns immediately The response if any will be sent as a separate operation at a later time Note that this method takes only one parameter the message being sent The messaging provider will use header information to determine the destination providerConnection send message JAXR 263 JAXR The Publishing and Discovering Web Services with JAXR page 347 JAXR provides a convenient way to access standard business registries over the Inter net Business registries are often described as electronic yellow pages because they contain listings of businesses and the products or services the businesses offer JAXR gives developers writing applications in the Java programming lan guage a uniform way to use business registries that are based on open standards such as ebXML or industry consortium led specifications such as UDDI Businesses can register themselves with a registry or discover other businesses with which they might want to do business In addition they can submit material to be shared and search for material that others have submitted Standards groups have developed schemas for particula
373. nt passed to setContent must be image jpeg to match the content being added The code for adding an image might look like the following For the first attachment the Object passed to the method setContent was a String In this case it is a stream AttachmentPart attachment2 message createAttachmentPartQ byte jpegData ByteArrayInputStream stream new ByteArrayInputStream jpegData attachment2 setContent stream image jpeg message addAttachmentPart attachment The other two SOAPMessage createAttachment methods create an Attach mentPart object complete with content One is very similar to the Attachment Part setContent method in that it takes the same parameters and does essentially the same thing It takes a Java Object containing the content and a String giving the content type As with AttachmentPart setContent the Object may be a String a stream a javax xm1 transform Source object or a javax activation DataHandler object You have already seen an example of using a Source object as content The next example will show how to use a DataHand ler object for content The other method for creating an AttachmentPart object with content takes a DataHandler object which is part of the JavaBeans Activation Framework JAF Using a DataHandler object is fairly straightforward First you create a 317 318 WEB SERVICES MESSAGING WITH JAXM java net URL object for the file you want to add as content T
374. o cedure to call to get prices and also the URI where the request is to be sent Her code makes the appropriate remote procedure calls using JAX RPC API and gets back the responses from the distributors The Coffee Break has been doing busi ness with one distributor for a long time and has made arrangements with it to CONCLUSION exchange JAXM messages using agreed upon XML schemas Therefore for this distributor the engineer s code uses JAXM API to request current prices and the distributor returns the price list in a JAXM message Companing Prices and Ordering Coffees Upon receiving the response to her request for prices the engineer processes the price lists using SAX She uses SAX rather than DOM because for simply com paring prices it is more efficient To modify the price list she would have needed to use DOM After her application gets the prices quoted by the differ ent vendors it compares them and displays the results When the owner and business manager decide which suppliers to do business with based on the engineer s price comparisons they are ready to send orders to the suppliers The orders to new distributors are sent via JAX RPC orders to the established distributor are sent via JAXM Each supplier whether using JAX RPC or JAXM will respond by sending a confirmation with the order number and shipping date Selling Coffees on the Intemet Meanwhile The Coffee Break has been preparing for its expanded cof
375. o the OrderRequest placeOrder method Name orderIDName envelope createNameC orderID SOAPE lement orderID order addChi ldElement CorderIDName orderID addTextNode orderBean getId The next element customer has several child elements that give information about the customer This information is also extracted from the Customer com ponent of OrderBean Name childName envelope createName customer SOAPElement customer order addChi1dElement chi 1dName childName envelope createName last name SOAPElement lastName customer addChi 1ldElement chi 1dName lastName addTextNode orderBean getCustomer getLastName childName envelope createName first name SOAPE lement firstName customer addChi1dElement chi 1dName firstName addTextNode orderBean getCustomer 408 THE COFFEE BREAK APPLICATION getFirstName childName envelope createName phone number SOAPElement phoneNumber customer addChi1dElement childName phoneNumber addTextNode orderBean getCustomer getPhoneNumber childName envelope createName email address SOAPElement emailAddress customer addChi 1dElement chi ldName emai 1lAddress addTextNode orderBean getCustomer getEmailAddress Q The address element added next has child elements for the street city state and zip code This information is extracted from the Address component of OrderBean childName envelope createName
376. o understand JAXM code SOAPPart soapPart message getSOAPPartQ SOAPEnvelope envelope soapPart getEnvelope XML it produces lt SOAP ENV Envelope xmIns SOAP ENV http schemas xmlsoap org soap envelope Cintervening elements omitted lt SOAP ENV Envelope gt CLIENT WITHOUT A MESSAGING PROVIDER 307 The outermost element in this XML example is the SOAP envelope element indicated by SOAP ENV Envelope Envelope is the name of the element and SOAP ENV is the namespace prefix The interface SOAPEnvelope represents a SOAP envelope The first line signals the beginning of the SOAP envelope element and the last line signals the end of it everything in between is part of the SOAP envelope The second line has an attribute for the SOAP envelope element xm1ns stands for XML namespace and its value is the URI of the namespace associated with Envelope This attribute is automatically included for you JAXM code SOAPBody body envelope getBody XML it produces lt SOAP ENV Body gt lt SOAP ENV Body gt These two lines mark the beginning and end of the SOAP body represented in JAXM by a SOAPBody object JAXM code Name bodyName envelope createName GetLastTradePrice m http wombat ztrade com SOAPBodyElement gltp body addBodyElement bodyName XML it produces lt m GetLastTradePrice xmlns m http wombat ztrade com gt lt m GetLastTradePrice gt These l
377. ock Duke s Bookstore Netscape tp localhost8000 bookstore2 enter Ma Duke s Ya Bookstore Thursday March 1 2001 11 53 52 AM PST What We re Reading In Web Components for Web Developers author Webster Masterson a world renowned guru on web development talks about how web components can transform the way you develop applications for the web This is a must read for any self respecting web developer Start Shopping Copyright 200 Sun Microsystems Inc Figure 4 3 Duke s Bookstore with Applet The jsp plugin element used to download the applet follows lt jsp plugin type applet code DigitalClock class codebase bookstore2 jreversion 1 4 align center height 25 width 300 lt jsp plugin type applet code DigitalClock class codebase bookstore2 jreversion 1 4 align center height 25 width 300 nspluginurl http java sun com j2se 1 4 download htm1 jepluginurl http java sun com j2se 1 4 download html gt lt jsp params gt JAVABEANS COMPONENTS IN JSP PAGES 103 lt jsp param name language value lt request getLocale getLanguage gt gt lt jsp param name country value lt request getLocale getCountryQ gt gt lt jsp param name bgcolor value FFFFFF gt lt jsp param name fgcolor value CCQ066 gt lt jsp params gt lt jsp fallback gt lt p gt Unable to start plugin lt p gt lt jsp fallback gt lt jsp plugin gt Ja
378. od 316 setNamespaceAware method 247 setPostalAddresess method 371 Simple API for XML Parsing See SAX Simple Object Access Protocol See SOAP SingleThreadModel 56 472 INDEX SMIL 197 SOAP 250 251 269 286 290 body 307 adding content 313 envelope 307 faults 319 part 257 populating 260 specification 250 SOAP with Attachments API for Java See SAAJ SOAPBody object 257 293 305 307 313 Content Type header 316 SOAPBodyElement object 305 307 313 332 SOAPConnection object 258 296 308 getting 302 SOAPConnection call method 339 SOAPElTement object 306 332 SOAPEnve lope class 293 SOAPEnve lope interface 307 SOAPFactory class 305 SOAPFault object 319 336 creating and populating 321 elements Detail object 320 fault code 320 fault string 320 SOAPFaultt object fault actor 320 SOAPFaultTest 336 running 338 SOAPHeader object 293 305 312 SOAPHeaderElement object 312 SOAPMessage class 293 SOAPMessage object 257 304 311 SOAPMessage getAttachments method 318 SOAPPart class 293 SOAPPart object 294 306 314 adding content 314 SOAPPart setContent method 314 SOAP RP profile 299 SOX 194 specifications 181 SQL viii 18 standalone 181 applications 324 client 301 308 See also client standalone client See client standalone static stubs 277 stubs 277 stylesheet 183 SVG 197 system properties com sun xml registry user TaxonomyFi lenames 369 T tag handlers life cycle 146 tag library descriptors 122 fil
379. of calling the method parse depends of course on how the methods in handler were implemented The SAX parser will go through the file priceList xml line by line calling the appropriate methods In addition to the methods already mentioned the parser will call other methods such as start Document endDocument ignorablewhiteSpace and processingInstructions but these methods still have their default implementations and thus do nothing The following method definitions show one way to implement the methods characters and startElement so that they find the price for Mocha Java and print it out Because of the way the SAX parser works these two methods work together to look for the name element the characters Mocha Java and the price element immediately following Mocha Java These methods use three flags to keep track of which conditions have been met Note that the SAX parser 243 244 INTRODUCTION TO WEB SERVICES will have to invoke both methods more than once before the conditions for print ing the price are met public void startElement String elementName if CelementName equals name inName true else ifCelementName equalsC price amp amp inMochaJava inPrice true inName false public void characters char buf int offset int len String s new String buf offset len if CinName amp amp s equals Mocha Java inMochaJava true inName false else if CinPrice Sy
380. ollows the SOAPHeader object if there 293 294 WEB SERVICES MESSAGING WITH JAXM is one provides a simple way to send mandatory information intended for the ultimate recipient If there is a SOAPFau1t object see SOAP Faults page 319 it must be in the SOAPBody object Messages with Attachments A SOAP message may include one or more attachment parts in addition to the SOAP part The SOAP part may contain only XML content as a result if any of the content of a message is not in XML format it must occur in an attachment part So if for example you want your message to contain an image file or plain text your message must have an attachment part for it Note that an attachment part can contain any kind of content so it can contain data in XML format as well Figure 10 2 shows the high level structure of a SOAP message that has two attachments The SAAJ API provides the AttachmentPart class to represent the attachment part of a SOAP message A SOAPMessage object automatically has a SOAPPart object and its required subelements but because AttachmentPart objects are optional you have to create and add them yourself The tutorial section will walk you through creating and populating messages with and without attachment parts A SOAPMessage object may have one or more attachments Each Attachment Part object has a MIME header to indicate the type of data it contains It may also have additional MIME headers to identify it or to give
381. omponents component contract The contract between a component and its container The contract includes life cycle management of the component a context interface that the instance uses to obtain various information and services from its container and a list of services that every container must provide for its components component managed sign on Security information needed for signing on to the resource to the getCon nection method is provided by an application component 432 connection See resource manager connection connection factory See resource manager connection factory connector A standard extension mechanism for containers to provide connectivity to enterprise information systems A connector is specific to an enterprise information system and consists of a resource adapter and application devel opment tools for enterprise information system connectivity The resource adapter is plugged in to a container through its support for system level con tracts defined in the connector architecture Connector element A representation of the interface between external clients sending requests to a particular service container An entity that provides life cycle management security deployment and runtime services to components container managed sign on Security information needed for signing on to the resource to the getCon nection method is supplied by the container context attribute An object bound into the c
382. on Life Cycle A Web application consists of Web components static resource files such as images and helper classes and libraries The Web container provides many sup porting services that enhance the capabilities of Web components and make them easier to develop However because it must take these services into account the process for creating and running a Web application is different from that of traditional stand alone Java classes The process for creating deploying and executing a Web application can be summarized as follows 1 Develop the Web component code including possibly a deployment descriptor 2 Build the Web application components along with any static resources for example images and helper classes referenced by the component 3 Install or deploy the application into a Web container 4 Access a URL that references the Web application Developing Web component code is covered in the later chapters Steps 2 through 4 are expanded on in the following sections and illustrated with a Hello WEB APPLICATION LIFE CYCLE 27 World style presentation oriented application This application allows a user to enter a name into an HTML form Figure 2 1 and then displays a greeting after the name is submitted Figure 2 2 My name is Duke What is yours Zeus Figure 2 1 Greeting Form fntp localhostB000 hello2 greeting usemame Zeus C My name is Duke What is yours Submit Reset Hello Zeu
383. on gt lt detai l gt lt soap env Fault gt lt soap env Body gt lt soap env Envelope gt SOAP fault contains fault code Client fault string Message does not have necessary info fault actor http gizmos com order Detail entry quantity element does not have a value Detail entry Incomplete address no zip code Starting the Application Server The UddiPing and SOAPFaultTest examples are standalone programs that is they do not run in a container The remaining examples run in a container If you have not already done so start the Sun ONE Application Server now and specify it as the default server for Web Tier Applications The JAXM Simple Example The JAXM Simple example shows how to send and receive a message using the local provider Note that a local provider should not be confused with a messag ing provider The local provider is simply a mechanism for returning the reply to a message that was sent using the method SOAPConnection cal1 Note that a message sent by this method will always be a request response message Run ning this example generates the files sent msg and reply msg which you will find in the server instance configuration directory To deploy and run the JAXM Simple example perform the following steps 1 Mount the following filesystem lt INSTALL gt j2eetutorial examples jaxm jaxm simple 2 In the Mount Web Module dialog that appears click OK to display the alternate view of the web module
384. onnection object rather than being a physical connection An application uses the connection object just as it usually does and is generally unaware that it is in any way different Connection pooling has no effect what ever on application code except that a pooled connection as is true with all con nections should always be explicitly closed When an application closes a connection that is pooled the connection is returned to a pool of reusable con nections The next time DataSource getConnection is called a handle to one of these pooled connections will be returned if one is available Because connec tion pooling avoids creating a new physical connection every time one is requested it can help to make applications run significantly faster The Duke s Bookstore examples use the PointBase database shipped with Sun ONE Application Server 7 to maintain the catalog of books This section describes how to e Start the PointBase database server e Populate the database e Add the PointBase JDBC driver to the application server s classpath e Define a data source in the application server e Configure a Web application to reference the data source with a JNDI name e Map the JNDI name to the data source defined in the application server Starting the PointBase Database Server The Sun ONE Application Server 7 is distributed with a development version of the PointBase database server To start the server 1 Open a terminal window 2 Na
385. onnectionFactory object and using it to create a connection The first two lines use the Java Naming and Directory Interface JNDI API to retrieve the appropriate ProviderConnectionFactory object from the naming service where it has been registered with the name CoffeeBreakProvider When this logical name is passed as an argument the method lookup returns the Provider ConnectionFactory object to which the logical name was bound The value returned is a Java Object which must be narrowed to a ProviderConnection Factory object so that it can be used to create a connection The third line uses a JAXM method to actually get the connection Context ctx getInitialContextQ ProviderConnectionFactory pcFactory ProviderConnectionFactory ctx lookup CoffeeBreakProvider ProviderConnection con pcFactory createConnectionQ The ProviderConnection instance con represents a connection to The Coffee Break s messaging provider Creating a Message As is true with connections messages are created by a factory And similar to the case with connection factories MessageFactory objects can be obtained in two ways The first way is to get an instance of the default implementation for the MessageFactory class This instance can then be used to create a basic SOAPMes sage object MessageFactory messageFactory MessageFactory newlInstance SOAPMessage m messageFactory createMessage All of the SOAPMessage objects that messa
386. ons that are made by security aware applications Program matic security is useful when declarative security alone is not sufficient to express the security model of a application prolog The part of an XML document that precedes the XML data The prolog includes the declaration and an optional DTD public key certificate Used in client certificate authentication to enable the server and optionally the client to authenticate each other The public key certificate is a digital equivalent of a passport It is issued by a trusted organization called a certif icate authority CA and provides identification for the bearer ABCDEFGHIJKLMNOPQRSTUVWXYZ ABCDEFGHIJKLMNOPQRSTUVWXYZ RDF Resource Description Framework A standard for defining the kind of data that an XML file contains Such information could help ensure semantic integrity for example by helping to make sure that a date is treated as a date rather than simply as text RDF schema A standard for specifying consistency rules that apply to the specifications contained in an RDF reference See entity reference realm See security policy domain Also a string passed as part of an HTTP request during basic authentication that defines a protection space The pro tected resources on a server can be partitioned into a set of protection spaces each with its own authentication scheme and or authorization database registry An infrastructure that enables the building deployment
387. ontext associated with a servlet Context element A representation of a Web application that is run within a particular virtual host context root A name that gets mapped to the document root of a Web application credentials The information describing the security attributes of a principal CSS Cascading Style Sheet A stylesheet used with HTML and XML documents to add a style to all elements marked with a particular tag for the direction of browsers or other presentation mechanisms 433 ABCDEFGHIJKLMNOPQRSTUVWXYZ data The contents of an element generally used when the element does not con tain any subelements When it does the more general term content is gener ally used When the only text in an XML structure is contained in simple elements and elements that have subelements have little or no data mixed in then that structure is often thought of as XML data as opposed to an XML document document In general an XML structure in which one or more elements contains text intermixed with subelements See also data DDP Document Driven Programming The use of XML to define applications declaration The very first thing in an XML document which declares it as XML The minimal declaration is lt xml version 1 0 gt The declaration is part of the document prolog declarative security Mechanisms used in an application that are expressed in a declarative syntax in a deployment descriptor delegation An act whereby o
388. ontinued and co authored The J2EE Tutorial Java API for XML Registries Java WSDP Registry Server Kim Haase is a staff writer with Sun Microsystems where she documents the J2EE platform In previous positions she has documented compilers debuggers and floating point programming She currently writes about the Java Message Service and the Java API for XML Registries She is a co author of Java Message Service API Tutorial and Reference A actors 300 addChildElement method 305 addClassifications method 363 addExternalLink method 368 addServiceBindings method 364 addServices method 364 addTextNode method 305 ANY 214 applet containers 13 applets 7 9 applications standalone 324 archiving 186 attachment part populating 261 AttachmentPart class 294 AttachmentPart object 315 creating 316 headers 316 attachments 294 adding 315 attributes 179 201 300 307 defining in DTD 216 encoding 181 mustUnderstand 300 standalone 181 types 217 version 181 Index attribute specification parameters 218 authentication for XML registries 361 B binding 186 binding templates adding to an organization with JAXR 363 finding with JAXR 360 body adding content 305 BufferedReader 60 businesses contacts 361 creating with JAXR 361 finding by name with JAXR 357 376 using WSDL documents with JAXR 377 finding by classification with JAXR 358 377 keys 361 365 registering 263 removing with JAXR 365 377 459 460 INDE
389. ontrolled by the container in which the servlet has been deployed When a request is mapped to a servlet the container performs the following steps 1 If an instance of the servlet does not exist the Web container a Loads the servlet class b Creates an instance of the servlet class c Initializes the servlet instance by calling the init method Initialization is covered in Initializing a Servlet page 58 2 Invokes the service method passing a request and response object Ser vice methods are discussed in Writing Service Methods page 59 If the container needs to remove the servlet it finalizes the servlet by calling the servlet s destroy method Finalization is discussed in Finalizing a Servlet page 79 51 52 JAVA SERVLET TECHNOLOGY Handling Serviet Life Cycle Events You can monitor and react to events in a servlet s life cycle by defining listener objects whose methods get invoked when life cycle events occur To use listener objects you Define the listener class e Specify the listener class in the Web application deployment descriptor Defining The Listener Class You define a listener class as an implementation of a listener interface Servlet Life Cycle Events page 52 lists the events that can be monitored and the corre sponding interface that must be implemented When a listener method is invoked it is passed an event that contains information appropriate to the event For example the methods in th
390. operty window for the file choose the Execution tab 3 Click Arguments then double click the ellipsis to bring up the property editor 4 Enter the pathname of uddi properties a space and Oracle If you are using the Sun ONE Studio UDDI Server Registry enter a string from a business name that you know is in the registry On a Windows system for example you need to specify something like this all on one line D j2eetutorial examples jaxm uddiping uddi properties Oracle 5 Click OK If you are on a Windows system notice that the pathname appears in the field with double backslashes 6 Right click the UddiPing file in the Filesystems tab and choose the Exe cute menu item This command compiles the source file then executes the class file THE UDDIPING EXAMPLE 335 The program output window displays the response message as follows all on one line lt xml version 1 0 encoding UTF 8 gt lt Envelope xmlIns http schemas xmlsoap org soap envelope gt lt Body gt lt businessList generic 1 0 xmlns urn uddi org api operator www ibm com services uddi truncated false gt lt businessInfos gt lt businessInfo businessKey 26B46510 81E8 11D5 A4A5 Q004AC49CC1E gt lt name gt Oracle lt name gt lt description xml lang en gt oracle powers the internet lt description gt lt serviceInfos gt lt serviceInfos gt lt businessInfo gt lt businessInfo businessKey 2ACAA2D0 82A7 11D5 A4A5 Q004AC49CC1E gt l
391. or creating your own solutions OVERVIEW If you are new to J2EE enterprise application development this chapter is a good place to start Here you will learn development basics be introduced to the J2EE architecture and APIs become acquainted with important terms and concepts and find out how to approach J2EE application programming assembly and deployment WEB SERVICES SUPPORT Web Services Support Web services are Web based enterprise applications that use open XML based standards and transport protocols to exchange data with calling clients The J2EE platform provides the XML APIs and tools you need to quickly design develop test and deploy Web services and clients that fully interoperate with other Web services and clients running on Java based or non Java based plat forms It is easy to write Web services and clients with the J2EE XML APIs All you do is pass parameter data to the method calls and process the data returned or for document oriented web services send documents containing the service data back and forth No low level programming is needed because the XML API implementations do the work of translating the application data to and from an XML based data stream that is sent over the standardized XML based transport protocols These XML based standards and protocols are introduced in the next sections The translation of data to a standardized XML based data stream is what makes Web services and clients written wi
392. ore3 template jsp of the forwarded page Finally the servlet dispatches the request to template jsp public class Dispatcher extends HttpServlet public void doGet HttpServletRequest request HttpServletResponse response request setAttribute selectedScreen request getServletPathQ RequestDispatcher dispatcher request getRequestDispatcher template jsp if dispatcher null dispatcher forward request response public void doPost HttpServletRequest request HttpServletResponse response request setAttribute selectedScreen request getServletPath RequestDispatcher dispatcher request getRequestDispatcher template jsp if dispatcher null dispatcher forward request response Tag Handlers The template tag library contains four tag handlers DefinitionTag ScreenTag ParameterTag and InsertTag that demonstrate the use of coop erating tags DefinitionTag ScreenTag and ParameterTag comprise a set of nested tag handlers that share public and private objects DefinitionTag creates a public object named definition that is used by InsertTag In doStartTag DefinitionTag creates a public object named screens that contains a hash table of screen definitions A screen definition consists of a screen identifier and a set of parameters associated with the screen 143 144 CUSTOM TAGS IN JSP PAGES public int doStartTag HashMap screens null screens HashMap pageContext getAttribute screens
393. orial lt xml version 1 0 encoding utf 8 gt This line identifies the document as an XML document that conforms to version 1 0 of the XML specification and says that it uses the 8 bit Unicode character encoding scheme For information on encoding schemes see Java Encoding Schemes page 425 Since the document has not been specified as standalone the parser assumes that it may contain references to other documents To see how to specify a docu ment as standalone see The XML Prolog page 181 Adding a Comment Comments are ignored by XML parsers A program will never see them in fact unless you activate special settings in the parser Add the text highlighted below to put a comment into the file lt xml version 1 encoding utf 8 gt lt A SAMPLE set of slides gt Defining the Root Element After the declaration every XML file defines exactly one element known as the root element Any other elements in the file are contained within that element WRITING A SIMPLE XML FILE 201 Enter the text highlighted below to define the root element for this file slide show lt xml version 1 encoding utf 8 gt lt A SAMPLE set of slides gt lt s1lideshow gt lt slideshow gt Note XML element names are case sensitive The end tag must exactly match the start tag Adding Attributes to an Bement A slide presentation has a number of associated data items none of which req
394. ose Deploy Testing the J AX RPC Service To test the service you create a Web service client and run the TestOrder Caller and TestPriceFetcher programs Contained in the test package these programs are static stub clients For more information see the section Static Stub Client Example page 277 Note The test programs assume that you have deployed SupplierService on localhost If you are running the service on a different host you need to update the service URLs 1 Right click the clientutil package and choose File New Web Ser vices Web Service Client 2 In the wizard s Specify Web Service Client pane do the following a In the Name field enter Order b In the Package field enter clientuti1 c For the Create From buttons choose Local WSDL File d Click Next BUILDING DEPLOYING AND REGISTERING THE JAX RPC SERVICE 419 3 In the wizard s Select Local WSDL File pane expand the service pack age and choose the SupplierService WSDL node a rectangle with a sphere in the lower left corner 4 Click Finish 5 Right click the Order client node and choose Generate Client Proxy This action creates the OrderGenClient package which contains the stub class serializer classes and other helper classes required by the client at runtime 6 In the test package execute TestOrderCaller The output window should display orderlId 123 shippingDate mm dd yy tomorrow s date 7 Execute TestPriceFetc
395. ot related to the content of the message it is simply a message to unblock the cal method CONNECTIONS Because the signature for the javax xm soap SOAPConnection call method changed in the SAAJ 1 1 specification a JAXM implementation may elect not to implement the call method To allow for this there is a new exception on the SOAPConnectionFactory class stating that SOAPConnection is not imple mented which allows for a graceful failure Unlike a client with no messaging provider which is limited to using only a SOAPConnection object a client that uses a messaging provider is free to use a SOAPConnection object or a ProviderConnection object It is expected that ProviderConnection objects will be used most of the time ProviderC onnection A ProviderConnection object represents a connection to a messaging provider The next section explains more about messaging providers When you send a message via a ProviderConnection object the message goes to the messaging provider The messaging provider forwards the message following the mes sage s routing instructions until the message gets to the ultimate recipient s mes saging provider which in turn forwards the message to the ultimate recipient When an application is using a ProviderConnection object it must use the method ProviderConnection send to send a message This method transmits the message one way and returns immediately without having to block until it gets a response
396. other sources and do the right things with it The latest information on namespaces can be found at http www w3 org TR REC xml names XSL Extensible Stylesheet Language The XML standard specifies how to identify data not how to display it HTML on the other hand told how things should be displayed without identifying what they were The XSL standard has two parts XSLT the transformation standard described next and XSL FO the part that covers formatting objects also known as flow objects XSL FO gives you the ability to define multiple areas on a page and then link them together When a text stream is directed at the collection it fills the first area and then flows into the second when the first area is filled Such objects are used by newsletters catalogs and periodical publications The latest W3C work on XSL is at http ww w3 org TR WD xs1 XSLT XPATH Extensible Stylesheet Language for Transformations The XSLT transformation standard is essentially a translation mechanism that lets you specify what to convert an XML tag into so that it can be displayed for example in HTML Different XSL formats can then be used to display the same data in different ways for different uses The XPATH standard is an addressing 191 192 UNDERSTANDING XML mechanism that you use when constructing transformation instructions in order to specify the parts of the XML structure you want to transform Schema Standar
397. ou can use a completely different stylesheet to produce output in postscript TEX PDF or some new format that hasn t even been invented yet That flexibility amounts to what one author described as future proofing your information The XML documents you author today can be used in future document delivery systems that haven t even been imagined yet Inline Reusa bility One of the nicer aspects of XML documents is that they can be composed from separate entities You can do that with HTML but only by linking to other docu ments Unlike HTML XML entities can be included in line in a document The included sections look like a normal part of the document you can search 183 184 UNDERSTANDING XML the whole document at one time or download it in one piece That lets you mod ularize your documents without resorting to links You can single source a sec tion so that an edit to it is reflected everywhere the section is used and yet a document composed from such pieces looks for all the world like a one piece document Linkability Thanks to HTML the ability to define links between documents is now regarded as a necessity The next section of this tutorial XML and Related Specs Digest ing the Alphabet Soup page 187 discusses the link specification initiative This initiative lets you define two way links multiple target links expanding links where clicking a link causes the targeted information to appear in
398. ou do not have access to a SOAPEnvelope object and thus need an alternate means of creat ing Name objects In addition to a method for creating Name objects the SOAPFac tory class provides methods for creating Detail objects and SOAP fragments You will find an explanation of Detail objects in the SOAP Fault sections Overview page 319 and Creating and Populating a SOAPFault Object page 321 Name objects associated with SOAPBody and SOAPHeader objects must be fully qualified that is they must be created with a local name a prefix for the namespace being used and a URI for the namespace Specifying a namespace for an element makes clear which one is meant if there is more than one element with the same local name The code fragment that follows retrieves the SOAPBody object body from envelope creates a Name object for the element to be added and adds a new SOAPBodyElement object to body SOAPBody body envelope getBody Name bodyName envelope createName GetLastTradePrice m http wombat ztrade com SOAPBodyElement gltp body addBodyE1ement bodyName At this point body contains a SOAPBodyElement object identified by the Name object bodyName but there is still no content in gltp Assuming that you want to get a quote for the stock of Sun Microsystems Inc you need to create a child element for the symbol using the method addChildElement Then you need to give it the stock symbol using the method addTextNo
399. owing output Received reply from http uddi ibm com testregistry inquiryapi lt xml version 1 0 encoding UTF 8 gt lt Envelope xmIns http schemas xmlsoap org soap enve lope gt lt Body gt lt businessList generic 1 0 xmlns urn uddi org api operator www ibm com services uddi truncated false gt lt businessInfos gt lt businessInfo businessKey D7475060 BF58 11D5 A432 0004AC49CC1E gt lt name gt Microsoft Corporation lt name gt lt description xml lang en gt Computer Software and Hardware Manufacturer lt description gt lt servicelnfos gt lt serviceInfos gt lt businessInfo gt lt businessiInfos gt lt businessList gt lt Body gt lt Envelope gt Content extracted from the reply message Microsoft Corporation Computer Software and Hardware Manufacturer The SOAPFaultlest Example The code SOAPFaultTest java based on the code fragments in a preceding section SOAP Faults page 319 creates a message with a SOAPFault object It then retrieves the contents of the SOAPFau1t object and prints them out You will find the code for SOAPFau1tTest in the following directory lt INSTALL gt j2eetutorial examples jaxm fault Here is the file SOAPFaultTest java import javax xml soap import java util public class SOAPFaultTest public static void main String args try MessageFactory msgFactory MessageFactory newInstance SOAPMessage msg msgFactory createMessage SOAPEnvelope
400. ows lt scripting language declaration gt When the scripting language is the Java programming language variables and methods in JSP declarations become declarations in the JSP page s servlet class 95 96 JAVASERVER PAGES TECHNOLOGY The bookstore example page initdestroy jsp defines an instance variable named bookDBAO and the initialization and finalization methods jspInit and jspDestroy discussed earlier in a declaration lt private BookDBAO bookDBAO public void jspInitQ public void jspDestroy gt Sc riptlets A JSP scriptlet is used to contain any code fragment that is valid for the scripting language used in a page The syntax for a scriptlet is as follows lt scripting language statements gt When the scripting language is set to java a scriptlet is transformed into a Java programming language statement fragment and is inserted into the service method of the JSP page s servlet A programming language variable created within a scriptlet is accessible from anywhere within the JSP page The JSP page showcart jsp contains a scriptlet that retrieves an iterator from the collection of items maintained by a shopping cart and sets up a construct to loop through all the items in the cart Inside the loop the JSP page extracts prop erties of the book objects and formats them using HTML markup Since the while loop opens a block the HTML markup is followed by a scriptlet that closes the block
401. page Provides a single API to manage the various scoped attributes described in Using Scope Objects page 55 This API is used extensively when implementing tag handlers see Tag Handlers page 125 request subtype of javax servilet ServletRequest The request triggering the execution of the JSP page See Getting Information from Requests page 60 response subtype of javax serviet ServletResponse The response to be returned to the client Not typi cally used by JSP page authors session javax servilet http HttpSession The session object for the client See Maintaining Client State page 76 Application Specifi Objects When possible application behavior should be encapsulated in objects so that page designers can focus on presentation issues Objects can be created by devel JAVASERVER PAGES TECHNOLOGY opers who are proficient in the Java programming language and in accessing databases and other services There are four ways to create and use objects within a JSP page e Instance and class variables of the JSP page s servlet class are created in declarations and accessed in scriptlets and expressions e Local variables of the JSP page s servlet class are created and used in scriptlets and expressions e Attributes of scope objects see Using Scope Objects page 55 are created and used in scriptlets and expressions e JavaBeans components can be created and accessed using stream
402. parts e A JAXR client a client program that uses the JAXR API to access a busi ness registry via a JAXR provider e A JAXR provider an implementation of the JAXR API that provides access to a specific registry provider or to a class of registry providers that are based on a common specification A JAXR provider implements two main packages e javax xml registry which consists of the API interfaces and classes that define the registry access interface e javax xml registry infomodel which consists of interfaces that define the information model for JAXR These interfaces define the types of objects that reside in a registry and how they relate to each other The basic interface in this package is the RegistryObject interface Its subinter faces include Organization Service and ServiceBinding The most basic interfaces in the javax xml registry package are e Connection The Connection interface represents a client session with a registry provider The client must create a connection with the JAXR pro vider in order to use a registry e RegistryService The client obtains a RegistryService object from its connection The RegistryService object in turn enables the client to obtain the interfaces it uses to access the registry 349 350 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR The primary interfaces also part of the javax xml registry package are e BusinessQueryManager which allows the client to search a registry
403. pe envelope part getEnvelope SOAPBody body envelope getBody JAXM SERVICE 399 Name bodyName envelope createName price list PriceList http sonata coffeebreak com SOAPBodyElement list body addBodyElement bodyName Name coffeeN envelope createName coffee SOAPElement coffee 1ist addChildElement coffeeN Name coffeeNm1 envelope createName coffee name SOAPElement coffeeName coffee addChi ldElement coffeeNm1 coffeeName addTextNodeC Arabica Name priceNamel envelope createName price SOAPElement pricel coffee addChi ldElement priceNamel1 pricel addTextNode 4 50 Name coffeeNm2 envelope createName coffee name SOAPElement coffeeName2 coffee addChi 1dElement coffeeNm2 coffeeName2 addTextNode Espresso Name priceName2 envelope createName price SOAPElement price2 coffee addChi ldElement priceName2 price2 addTextNode 5 00 Name coffeeNm3 envelope createName coffee name SOAPElement coffeeName3 coffee addChi 1dElement coffeeNm3 coffeeName3 addTextNode Dorada Name priceName3 envelope createName price SOAPElement price3 coffee addChi ldElement priceName3 price3 addTextNode 6 00 Name coffeeNm4 envelope createName coffee name SOAPElement coffeeName4 coffee addChi 1dElement coffeeNm4 coffeeName4 addTextNode House Blend Name priceName4 envelope createName price SOAPElement price4
404. pecify Web Service pane do the following a In the Name field enter SupplierService b In the Package field enter service c For the Create From buttons choose Java Methods d For the Architecture buttons choose Web centric e Click Next BUILDING DEPLOYING AND REGISTERING THE JAX RPC SERVICE 6 In the wizard s Select Methods pane do the following a Expand the nodes in the service package until you see the methods beneath the Supplier class b Choose the getPriceList and placeOrder methods These are the methods that remote clients may call c Click Finish If the Collection of What window appears click Cancel In Sun ONE Studio 4 update 1 a bug prevents this operation from working correctly In the Explorer the IDE displays a Web service node a cube containing a sphere for the SupplierService Specifying the Senalizers The JAX RPC runtime system uses serializers when converting Java objects into XML data types The runtime system needs a serializer for every parameter and return type of the service s methods The IDE generates the serializers automati cally when you perform the Generate Web Service task as in the next section The IDE identifies the serializers it needs to generate by examining the classes of the parameters and return types However if such a class contains a collection the IDE cannot automatically identify the type of the collection s members In this case you must specify th
405. perty of a Java Beans component using the jsp setProperty element Table 4 3 Setting JavaBeans Component Properties lt jsp setProperty name beanName String constant property propName value string constant gt lt jsp setProperty name beanName Request parameter property propName param paramName gt lt jsp setProperty name beanName Request parameter property propName gt name matches bean property lt jsp setProperty name beanName property gt lt jsp setProperty name beanName Expression property propName value lt expression gt gt 1 beanName must be the same as that specified for the id attribute in a useBean element 2 There must be a setPropName method in the JavaBeans compo nent 3 paramName must be a request parameter name A property set from a constant string or request parameter must have a type listed in Table 4 4 Since both a constant and request parameter are strings the Web container automatically converts the value to the property s type the con version applied is shown in the table String values can be used to assign values to a property that has a PropertyEditor class When that is the case the setAs Text String method is used A conversion failure arises if the method throws 107 108 JAVASERVER PAGES TECHNOLOGY an I1legalArgumentException The value assigned to an indexed property must be an array and the rules just described a
406. pical scenario a business uses a messaging provider it is also possible to do JAXM messaging without using a messaging provider In this case the JAXM client called a standalone client is limited to sending point to point messages directly to a Web service that is implemented for request response messaging Request response messaging is synchronous meaning that a request is sent and its response is received in the same operation A request response message is sent over a SOAPConnection object via the method SOAP Connection call which sends the message and blocks until it receives a response A standalone client can operate only in a client role that is it can only send requests and receive their responses In contrast a JAXM client that uses a messaging provider may act in either the client or server service role In the cli ent role it can send requests in the server role it can receive requests process them and send responses Though it is not required JAXM messaging usually takes place within a con tainer generally a servlet container or J2EE server A Web service that uses a messaging provider and is deployed in a container has the capability of doing one way messaging meaning that it can receive a request as a one way message and can return a response some time later as another one way message Because of the features that a messaging provider can supply JAXM can some times be a better choice for SOAP messaging than JAX R
407. ples web date directory created when you unzip the tutorial bundle The JSP page index jsp used to create the form appears below it is a typical mixture of static HTML markup and JSP elements If you have developed Web pages you are probably familiar with the HTML document structure statements lt head gt lt body gt and so on and the HTML statements that create a form lt form gt and a menu lt select gt The lines in bold in the example code contains the following types of JSP con structs e Directives lt page gt import classes in the java util package and the MyLocales class and set the content type returned by the page e The jsp useBean element creates an object containing a collection of locales and initializes a variable that points to that object e Scriptlets lt gt retrieve the value of the locale request parameter iterate over a collection of locale names and conditionally insert HTML text into the output e Expressions lt gt insert the value of the locale name into the response WHAT Is A JSP PAGE 85 e The jsp include element sends a request to another page date jsp and includes the response in the response from the calling page lt page import java util MyLocales gt lt page contentType text html charset ISO 8859 5 gt lt html gt lt head gt lt title gt Localized Dates lt title gt lt head gt lt body bgcolor white gt lt jsp useBean id locale
408. pply to the elements Table 4 4 Valid Value Assignments Property Type Conversion on String Value Bean Property Uses setAsText string literal boolean or Boolean As indicated in java lang Boolean valueOf String byte or Byte As indicated in java lang Byte valueOf String char or Character As indicated in java lang String charAt Q double or Double As indicated in java lang Double valueOf String int or Integer As indicated in java lang Integer valueOf String float or Float As indicated in java lang Float valueOf String long or Long As indicated in java lang Long valueOf String short or Short As indicated in java lang Short valueOf String Object new String string literal You would use a runtime expression to set the value of a property whose type is a compound Java programming language type Recall from Expressions page 98 that a JSP expression is used to insert the value of a scripting language expression converted into a String into the stream returned to the client When used within a setProperty element an expression simply returns its value no automatic conversion is performed As a consequence the type returned from an expression must match or be castable to the type of the property The Duke s Bookstore application demonstrates how to use the setProperty element and a scriptlet to set the current book for the database helper bean For example bookstore3
409. program It deletes the organization that corresponds to a specified key string and then displays the key again so that the user can confirm that it has deleted the correct one String id key getIdQ System out printInC Deleting organization with id id Collection keys new ArrayListQ keys add key BulkResponse response blcm deleteOrganizations keys Collection exceptions response getException if exceptions null System out printInC Organization deleted Collection retKeys response getCollection 365 366 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR Iterator keyIter retKeys iteratorQ javax xml registry infomodel Key orgKey null if CkeyIter hasNextQ orgKey javax xml registry infomodel Key keyIter next id orgKey getIdQ System out printInC Organization key was id A client can use a similar mechanism to delete services and service bindings Using Taxonomies in J AXR Clients In the JAXR API a taxonomy is represented by a ClassificationScheme object This section describes how to use the implementation of JAXR in the Sun ONE Application Server e To define your own taxonomies e To specify postal addresses for an organization Defning a Taxonomy The JAXR specification requires a JAXR provider to be able to add user defined taxonomies for use by JAXR clients The mechanisms clients use to add and administer these taxonomies are implementation specific T
410. ps sourceforge net forum forum php forum_id 197238 e Java Technology and XML http java sun com xm1 e Java Technology amp Web Services http java sun com webservices index htm 12 The Coffee Break Application Stephanie Bodoff Maydene Fisher Dale Green Kim Haase The introduction to this tutorial introduced a scenario in which an application The Coffee Break is constructed using Web services Now that we have dis cussed all the technologies necessary to build Web applications and Web ser vices this chapter describes an implementation of the scenario described in Chapter 8 Coffee Break Overview The Coffee Break sells coffee on the Internet Customers communicate with the Coffee Break server to order coffee online The server consists of Java Servlets JSP pages and JavaBeans components A customer enters the quantity of each coffee to order and clicks the Submit button to send the order The Coffee Break does not maintain any inventory It handles customer and order management and billing Each order is filled by forwarding suborders to one or more coffee distributors This process is depicted in Figure 12 1 383 384 THE COFFEE BREAK APPLICATION Briseann A Service siar service pricas JAKA r_cofice JAZM JAX AP Figure 12 1 Coffee Break Application Flow The Coffee Break server obtains the coffee varieties it sells and their prices by querying distributors at startup and on deman
411. r Fetc hing the Price List This operation is implemented by the getPriceList method of the jaxrpc service Supplier The getPriceList method returns a PriceList Bean object which lists the name and price of each type of coffee that can be ordered from this service The getPriceList method creates the PriceList Bean object by invoking a private method named loadPrices In a production application the loadPrices method would fetch the prices from a database However our loadPrices method takes a shortcut by invoking Price Loader loadItems a method with hardcoded prices Here are the get PriceList and loadPrices methods public PriceListBean getPriceList Q PriceListBean priceList loadPricesQ return priceList private PriceListBean loadPrices Date today new DateQ Date endDate DateHelper addDays today 30 Collection priceItems PriceLoader loadItems PriceListBean priceList new PriceListBean priceList setStartDate today priceList setEndDate endDate priceList setPriceItems priceltems return priceList 386 THE COFFEE BREAK APPLICATION Placing an Order The placeOrder method of jaxrpc service Supplier accepts as input a cof fee order and returns a confirmation for the order To keep things simple the placeOrder method confirms every order and sets the ship date in the confirma tion to the next day This date is calculated by DateHelper a utility class that resides in the jaxrpc ser
412. r files Click OK 9 Click OK in the property editor then click Close in the Options window NYDN fF WN o0 The JARs are also located in the lt S1STUDIO_HOME gt jwsdp common lib directory so you may specify that location for the classpath if you prefer 415 416 THE COFFEE BREAK APPLICATION Building Deploying and Registenng the J AX RPC Service This section contains step by step instructions for the following tasks e Creating the JAX RPC Service e Specifying the Serializers e Generating the Service s WSDL File Serializers and other Helper Classes e Deploying the JAX RPC Service e Testing the JAX RPC Service e Registering the JAX RPC Service Creating the J AX RPC Service 1 In the IDE mount this filesystem lt INSTALL gt j2eetutorial examples cb jaxrpc 2 Expand the jaxrpc node 3 Compile the beans registry and service packages The beans package contains JavaBeans components that represent business information such as AddressBean In the JAX RPC service s methods these beans are parameters or return types The registry package holds the JAXR programs that publish the service in and remove it from the registry The service package contains DateHelper a utility class PriceLoader which loads coffee prices into a list and Supplier which implements the service s remote procedures 4 Right click the service package and choose New Web Services Web Service 5 In the wizard s S
413. r kinds of XML documents and two busi nesses might for example agree to use the schema for their industry s standard purchase order form Because the schema is stored in a standard business regis try both parties can use JAXR to access it Registries are becoming an increasingly important component of Web services because they allow businesses to collaborate with each other dynamically in a loosely coupled way Accordingly the need for JAXR which enables enterprises to access standard business registries from the Java programming language is also growing Using J AXR The following sections give examples of two of the typical ways a business reg istry is used They are meant to give you an idea of how to use JAXR rather than to be complete or exhaustive Registering a Business An organization that uses the Java platform for its electronic business would use JAXR to register itself in a standard registry It would supply its name a descrip tion of itself and some classification concepts to facilitate searching for it This is shown in the following code fragment which first creates the RegistrySer vice object rs and then uses it to create the BusinessLifeCycleManager object 1cm and the BusinessQueryManager object bqm The business a chain of coffee houses called The Coffee Break is represented by the Organization object org to which The Coffee Break adds its name a description of itself and its classifi 264 INTRODUCTIO
414. r of spices could be in the con sumer role when it uses a Web service to check on the availability of vanilla beans and in the provider role when it supplies prospective customers with dif ferent vendors prices for vanilla beans 239 240 INTRODUCTION TO WEB SERVICES The Role of XMLand the Java Platform Web services depend on the ability of parties to communicate with each other even if they are using different information systems Extensible Markup Lan guage XML a markup language that makes data portable is a key technolugy in addressing this need Enterprises have discovered the benefits of using XML for the integration of data both internally for sharing legacy data among depart ments and externally for sharing data with other enterprises As a result XML is increasingly being used for enterprise integration applications both in tightly coupled and loosely coupled systems Because of this data integration ability XML has become the underpinning for Web related computing Web services also depend on the ability of enterprises using different computing platforms to communicate with each other This requirement makes the Java platform which makes code portable the natural choice for developing Web ser vices This choice is even more attractive as the new Java APIs for XML become available making it easier and easier to use XML from the Java programm ng language These APIs are summarized later in this introduction and explain
415. r out response getWriterQ then write the response out printin C lt htm1 gt lt head gt lt title gt messages getString TitleBookDescription lt title gt lt head gt Get the dispatcher it gets the banner to the user RequestDispatcher dispatcher getServletContextQ getRequestDispatcher banner if dispatcher null dispatcher include request response Get the identifier of the book to display String bookId request getParameter bookId if bookId null and the information about the book try BookDetails bd bookDB getBookDetai 1s bookId Print out the information obtained out printInC lt h2 gt bd getTitleQ lt h2 gt catch BookNotFoundException ex response resetBufferQ throw new ServletException ex 64 JAVA SERVLET TECHNOLOGY out printin lt body gt lt htm1 gt out close BookDetai lsServlet generates a page that looks like tp localhost8000 bookstorel bookdetails bookide203 aly Duke s A Bookstore Web Components for Web Developers By Webster Masterson 2000 Here s what the critics say What a cool book Our price 17 75 Add To Your Shopping Cart Continue Shopping Figure 3 2 Book Details Filtering Requests and Responses A filter is an object that can transform the header and content or both of a request or response Filters differ from Web components in that they usually do not thems
416. rability Various network interop erability standards groups such as the World Wide Web Consortium W3C and the Organization for the Advancement of Structured Information Standards OASIS have been defining standard ways of doing things so that businesses who follow these standards can make their data and applications work together Another feature of the Java APIs for XML is that they allow a great deal of flex ibility Users have flexibility in how they use the APIs For example JAXP code can use various tools for processing an XML document and JAXM code can use various messaging protocols on top of SOAP Implementers have flexibility as well The Java APIs for XML define strict compatibility requirements to ensure 242 INTRODUCTION TO WEB SERVICES that all implementations deliver the standard functionality but they also give developers a great deal of freedom to provide implementations tailored to spe cific uses The following sections discuss each of these APIs giving an overview and a feel for how to use them J AXP The Java API for XML Processing JAXP makes it easy to process XML data using applications written in the Java programming language JAXP leverages the parser standards SAX Simple API for XML Parsing and DOM Document Object Model so that you can choose to parse your data as a stream of events or to build a tree structured representation of it The latest versions of JAXP also support the XSLT XML Stylesheet
417. rating serv lets e Information about the protocol used to communicate the request and the client and server involved in the request Information relevant to localization For example in CatalogServlet the identifier of the book that a customer wishes to purchase is included as a parameter to the request The following code fragment illustrates how to use the getParameter method to extract the identi fier String bookId request getParameter Add if bookId null BookDetails book bookDB getBookDetai 1s bookId You can also retrieve an input stream from the request and manually parse the data To read character data use the BufferedReader object returned by the request s getReader method To read binary data use the ServletInputStream returned by getInputStream HTTP servlets are passed an HTTP request object HttpServletRequest which contains the request URL HTTP headers query string and so on An HTTP request URL contains the following parts http host port request path query string The request path is further composed of the following elements e Context path A concatenation of a forward slash with the context root of the servlet s Web application e Servlet path The path section that corresponds to the component alias that activated this request This path starts with a forward slash GETTING INFORMATION FROM REQUESTS e Path info The part of the request path that is not part of th
418. rce doc The following two lines of code access the SOAPPart object using the SOAPMes sage object message and set the new DOMSource object as its content The method SOAPPart setContent not only sets content for the SOAPBody object but also sets the appropriate header for the SOAPHeader object SOAPPart soapPart message getSOAPPart soapPart setContent domSource You will see other ways to add content to a message in the section on Attach mentPart objects One big difference to keep in mind is that a SOAPPart object must contain only XML data whereas an AttachmentPart object may contain any type of content Sending the Message When the connection is a ProviderConnection object messages have to be sent using the method ProviderConnection send This method sends the message passed to it and returns immediately Unlike the SOAPConnection method call it does not have to block until it receives a response which leaves the application free to do other things The send method takes only one argument the message to be sent It does not need to be given the destination because the messaging provider can use infor mation in the header to figure out where the message needs to go pcCon send message pcCon closeQ Adding Attachments Adding AttachmentPart objects to a message is the same for all clients whether they use a messaging provider or not As noted in earlier sections you 316 WEB SERVICES MESSAGING WITH JAXM
419. re Method can take the value Get Delete Options Post Put Trace of an HttpServlet or any other protocol specific methods defined by a class that implements the Servlet interface In the rest of this chapter the term service method will be used for any method in a servlet class that provides a service to a client The general pattern for a service method is to extract information from the request access external resources and then populate the response based on that information For HTTP servlets the correct procedure for populating the response is to first fill in the response headers then retrieve an output stream from the response and finally write any body content to the output stream Response headers must always be set before a PrintWriter or ServletOutputStream is retrieved because the HTTP protocol expects to receive all headers before body content The next two sections describe how to get information from requests and gener ate responses 59 60 JAVA SERVLET TECHNOLOGY Getting Information from Requests A request contains data passed between a client and the servlet All requests implement the ServletRequest interface This interface defines methods for accessing the following information e Parameters which are typically used to convey information between cli ents and servlets e Object valued attributes which are typically used to pass information between the servlet container and a servlet or between collabo
420. re XML encodes the data for a program to process e Document driven programming where XML documents are containers that build interfaces and applications from existing components e Archiving the foundation for document driven programming where the customized version of a component is saved archived so it can be used later e Binding where the DTD or schema that defines an XML data structure is used to automatically generate a significant portion of the application that will eventually process that data Traditional Data Processing XML is fast becoming the data representation of choice for the Web It s terrific when used in conjunction with network centric Java platform programs that send and retrieve information So a client server application for example could transmit XML encoded data back and forth between the client and the server In the future XML is potentially the answer for data interchange in all sorts of transactions as long as both sides agree on the markup to use For example should an e mail program expect to see tags named lt FIRST gt and lt LAST gt or lt FIRSTNAME gt and lt LASTNAME gt The need for common standards will generate a lot of industry specific standardization efforts in the years ahead In the mean time mechanisms that let you translate the tags in an XML document will be important Such mechanisms include projects like the RDF page 196 initiative which defines meat tags and
421. register with the Sun ONE Studio internal UDDI Server Reg istry in order to add or update data You can use the default user name and pass word testuser and testuser 352 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR Note The JAXR API has been tested with the Microsoft and IBM registries and with the Registry Server but not with the SAP registry Creating or Looking Up a Connection Factory A client creates a connection from a connection factory A JAXR provider may supply one or more preconfigured connection factories that clients can obtain by looking them up using the Java Naming and Directory Interface JNDD API At this release of the Sun ONE Application Server JAXR does not supply pre configured connection factories Instead a client creates an instance of the abstract class ConnectionFactory import javax xml registry ConnectionFactory connFactory ConnectionFactory newInstance Creating a Connection To create a connection a client first creates a set of properties that specify the URL or URLs of the registry or registries being accessed For example the fol lowing code provides the URLs of the query service and publishing service for the IBM test registry There should be no line break in the strings Properties props new Properties props setProperty javax xml registry queryManagerURL http uddi ibm com testregistry inquiryapi props setProperty javax xml registry 1ifeCycleM
422. rface Result public String getColumnNames public int getRowCount public Map getRows public Object getRowsByIndexQ public boolean isLimitedByMaxRows For complete information about this interface see the API documentation for the javax servlet jsp jstl sql package The var attribute set by a query tag is of type Result The getRows method returns an array of maps that can be supplied to the items attribute of a forEach tag The JSTL expression language converts the syntax resu7t rows to a QUERY TAG RESULT INTERFACE call to resu7t getRows The expression books rows in the following exam ple returns an array of maps When you provide a array of maps to the forEach tag the var attribute set by the tag is of type Map To retrieve information from a row use the get colname method to get a column value The JSTL expression language converts the syntax map colname to a call to map get colname For example the expression book title returns the value of the title entry of a book map The Duke s Bookstore page bookdetails jsp retrieves the column values from the book map as follows lt c forEach var book begin 0 items books rows gt lt h2 gt lt c out value book title gt lt h2 gt amp nbsp lt fmt message key By gt lt em gt lt c out value book firstname gt lt c out value book surname gt lt em gt amp nbsp amp nbsp lt c out value book year gt lt
423. ript lets For example the following scriptlet is used to iterate through a shopping cart lt Iterator i cart getItems iteratorQ while i hasNextQ ShoppingCartItem item CShoppingCartItem i nextQ lt tr gt lt td align right bgcolor ffffff gt lt i tem getQuantity gt lt td gt Flow control tags eliminate the need for scriptlets The next two sections have examples that demonstrate the conditional and iterator tags Conditional Tags The if tag allows the conditional execution of its body according to value of a test attribute The following example from catalog jsp tests whether the request parameter Add is empty If the test evaluates to true the page queries the 161 162 JAVASERVER PAGES STANDARD TAG LIBRARY database for the book record identified by the request parameter and adds the book to the shopping cart lt c if test empty param Add gt lt c set var bid value param Add gt lt jsp useBean id bid type java lang String gt lt sql query var books dataSource applicationScope bookDS gt select from PUBLIC books where id lt sql param value bid gt lt sql query gt lt c forEach var bookRow begin 0 items books rows gt lt jsp useBean id bookRow type java util Map gt lt jsp useBean id addedBook class database BookDetails scope page gt lt cart add bid addedBook gt lt c if gt The choose tag performs condit
424. rite URLs returned from a JSP page The tag includes the session ID in the URL only if cookies are disabled otherwise it returns the URL XML TAGS 165 unchanged Note that this feature requires the URL to be relative The url tag takes param subtags for including parameters in the returned URL For example catalog jsp rewrites the URL used to add a book to the shopping cart as fol lows lt ciurl var url value catalog gt lt C param name Add value bookId gt lt c url gt lt p gt lt strong gt lt a href lt c out value url gt gt The redirect tag sends an HTTP redirect to the client The redirect tag takes param subtags for including parameters in the returned URL XML lags A key aspect of dealing with XML documents is to be able to easily access their content XPath a W3C recommendation since 1999 provides an easy notation for specifying and selecting parts of an XML document The JSTL XML tag set listed in Table 6 4 is based on XPath Table 6 4 XML Tags Function Tags out parse set choose when Flow Control otherwise forEach if transform param Transformation The XML tags use XPath as a local expression language XPath expressions are always specified using attribute select This means that only values specified for select attributes are evaluated using the XPath expression language All 166 JAVASERVER PAGES STANDARD TAG LIBRARY other attributes are evaluate
425. riter flushQ filterConfig getServletContextQ log sw getBuffer toStringQ chain doFilter request wrapper Programming Customized Requests and Responses There are many ways for a filter to modify a request or response For example a filter could add an attribute to the request or insert data in the response In the Duke s Bookstore example HitCounterFilter inserts the value of the counter into the response A filter that modifies a response must usually capture the response before it is returned to the client The way to do this is to pass a stand in stream to the servlet that generates the response The stand in stream prevents the servlet from closing the original response stream when it completes and allows the filter to modify the servlet s response To pass this stand in stream to the servlet the filter creates a response wrapper that overrides the getWriter or getOutputStream method to return this stand in stream The wrapper is passed to the doFilter method of the filter chain Wrap per methods default to calling through to the wrapped request or response object This approach follows the well known Wrapper or Decorator pattern described in Design Patterns Elements of Reusable Object Oriented Software Addison Wesley 1995 The following sections describe how the hit counter filter described earlier and other types of filters use wrappers To override request methods you wrap the request in an object that extends Se
426. rmer from the TransformerFactory object tFactory TransformerFactory tFactory TransformerFactory newInstance String stylesheet prices xs1 String sourcelId newXML xm1 File pricesHTML new FileC pricesHTML htm1 FileOutputStream os new FileOutputStream pricesHTML Transformer transformer tFactory newTransformer new StreamSource stylesheet The transformation is accomplished by invoking the transform method passing it the data and the output stream transformer transform new StreamSource sourceld new StreamResult os J AX RPC The Building Web Services With JAX RPC page 269 JAX RPC is the Java API for developing and using Web services Overview of J AX RPC An RPC based Web service is a collection of procedures that can be called by a remote client over the Internet For example a typical RPC based Web service is a stock quote service that takes a SOAP Simple Object Access Protocol request for the price of a specified stock and returns the price via SOAP Note The SOAP 1 1 specification available from http www w3 org defines a framework for the exchange of XML documents It specifies among other things what is required and optional in a SOAP message and how data can be encoded and transmitted JAX RPC and JAXM are both based on SOAP A Web service a server application that implements the procedures that are available for clients to call is deployed on a server side Web contain
427. rocessing instructions have the following format lt target instructions gt where the target is the name of the application that is expected to do the process ing and instructions is a string of characters that embodies the information or commands for the application to process Since the instructions are application specific an XML file could have multiple processing instructions that tell different applications to do similar things though in different ways The XML file for a slideshow for example could have processing instructions that let the speaker specify a technical or executive level version of the presentation If multiple presentation programs were used the pro gram might need multiple versions of the processing instructions although it would be nicer if such applications recognized standard instructions Note The target name xml in any combination of upper or lowercase letters is reserved for XML standards In one sense the declaration is a processing instruc tion that fits that standard However when you re working with the parser later you ll see that the method for handling processing instructions never sees the dec laration Why Is XML Important There are a number of reasons for XML s surging acceptance This section lists a few of the most prominent Plain Text Since XML is not a binary format you can create and edit files with anything from a standard text editor to a visual dev
428. rowser 35 INTRODUCTION TO WEB APPLICATIONS You should see the screen in Figure 2 3 in the browser S Netscape Hello File Edit View Go Communicator Help i 6 Bookmarks 4 Location http localhost 8080 hello1 greeting 1 Hi my name is Duke What s yours I Submit Reset p E 100 Document Done i Figure 2 3 New Greeting Undeploying Web Modules You can undeploy a Web module with the application server administration tool or the IDE To undeploy a Web module with the application server administration tool 1 Open the URL http localhost 4848 admin in a browser 2 Select the server1 node 3 Expand the Applications node 4 Select the Web Apps node 5 Select the checkbox next to he1101 and click the Undeploy button To undeploy a Web application with the IDE 1 Select the Runtime tab in the Explorer 2 Expand the nodes Server Registry Installed Servers Sun ONE Applica tion Server 7 localhost 4848 server1 Deployed Web Modules 3 Right click he1101 and choose Undeploy DUKE S BOOKSTORE Duke s Bookstore In the next 5 chapters a common example Duke s Bookstore is used to illus trate the elements of Java Servlet technology JavaServer Pages technology and the JSP Standard Tag Library The example emulates a simple online shopping application It provides a book catalog from which users can select books and add them to a
429. rsonnel involved in Web page design thus do not need to under stand Java programming language syntax to do their jobs Application Clients A J2EE application client runs on a client machine and provides a way for users to handle tasks that require a richer user interface than can be provided by a markup language It typically has a graphical user interface GUI created from Swing or Abstract Window Toolkit AWT APIs but a command line interface is certainly possible OVERVIEW Application clients directly access enterprise beans running in the business tier However if application requirements warrant it a J2EE application client can open an HTTP connection to establish communication with a servlet running in the Web tier JavaBeans Component Architecture The server and client tiers might also include components based on the Java Beans component architecture JavaBeans component to manage the data flow between an application client or applet and components running on the J2EE server or between server components and a database JavaBeans components are not considered J2EE components by the J2EE specification JavaBeans components have instance variables and get and set methods for accessing the data in the instance variables JavaBeans components used in this way are typically simple in design and implementation but should conform to the naming and design conventions outlined in the JavaBeans component archi tecture J 2EE Se
430. rted JSP application A stand alone Web application written using the JavaServer Pages technol ogy that can contain JSP pages servlets HTML files images applets and JavaBeans components JSP container A container that provides the same services as a servlet container and an engine that interprets and processes JSP pages into a servlet 441 JSP container distributed A JSP container that can run a Web application that is tagged as distributable and is spread across multiple Java virtual machines that might be running on different hosts JSP declaration A JSP scripting element that declares methods variables or both in a JSP file JSP directive A JSP element that gives an instruction to the JSP container and is inter preted at translation time JSP element A portion of a JSP page that is recognized by a JSP translator An element can be a directive an action or a scripting element JSP expression A scripting element that contains a valid scripting language expression that is evaluated converted to a String and placed into the implicit out object JSP file A file that contains a JSP page In the Servlet 2 2 specification a JSP file must have a jsp extension JSP page A text based document using fixed template data and JSP elements that describes how to process a request to create a response JSP scripting element A JSP declaration scriptlet or expression whose tag syntax is defined by the JSP specification
431. rticular type of document A document may be compared with the rules in the DTD to determine its validity and to locate particular elements in the document Web services application s deployment descriptors are expressed in XML with DTDs defining allowed elements Programs for processing XML documents use SAX or DOM APIs XML registry See registry 455 XML Schema The W3C schema specification for XML documents XPath See XSL XPointer The part of the XLL specification that is concerned with identifying sections of documents so that they can referenced in links or included in other docu ments XSL Extensible Stylesheet Language Extensible Stylesheet Language An important standard that achieves several goals XSL lets you a Specify an addressing mechanism so you can identify the parts of an XML file that a transformation applies to XPath b Specify tag conversions so you convert XML data into a different formats XSLT c Specify display characteristics such page sizes margins and font heights and widths as well as the flow objects on each page Information fills in one area of a page and then automatically flows to the next object when that area fills up That allows you to wrap text around pictures for example or to con tinue a newsletter article on a different page XML FO XSL FO A subcomponent of XSL used for describing font sizes page layouts and how information flows from one page to another XSL
432. rver Communications Figure 1 2 shows the various elements that can make up the client tier The cli ent communicates with the business tier running on the J2EE server either directly or as in the case of a client running in a browser by going through JSP pages or servlets running in the Web tier Your J2EE application uses a thin browser based client or thick application cli ent In deciding which one to use you should be aware of the trade offs between keeping functionality on the client and close to the user thick client and off loading as much functionality as possible to the server thin client The more functionality you off load to the server the easier it is to distribute deploy and manage the application however keeping more functionality on the client can make for a better perceived user experience WEB COMPONENTS Client Tier J2EE Server Figure 1 2 Server Communications Web Components J2EE Web components can be either servlets or JSP pages Servlets are Java pro gramming language classes that dynamically process requests and construct responses JSP pages are text based documents that execute as servlets but allow a more natural approach to creating static content Static HTML pages and applets are bundled with Web components during appli cation assembly but are not considered Web components by the J2EE specifica tion Server side utility classes can also be bundled with Web components and like HTM
433. rvice from the registry by calling executeRemove Here is the source code for the OrgRemover program package jaxrpc registry import java util ResourceBundle import javax xml registry import javax xml registry infomodel Key import java io public class OrgRemover Connection connection null public static void main String args String keyStr null ResourceBundle registryBundle ResourceBundle getBundle jaxrpc registry CoffeeRegistry 391 392 THE COFFEE BREAK APPLICATION String queryURL registryBundle getString query url String publishURL registryBundle getStringC publish url String username registryBundle getString registry username String password registryBundle getString registry password String keyFile registryBundle getString key file try FileReader in new FileReader keyFi le char buf new char 512 while Cin read buf 0 512 gt 0 in closeQ keyStr new String buf trimQ catch IOException ex System out printIn Cex getMessage JAXRRemover remover new JAXRRemover remover makeConnection queryURL publishURL javax xml registry infomodel Key modelKey null modelKey remover createOrgKey keyStr remover executeRemove modelKey username password Instantiated by the OrgRemover program the JAXRRemover class contains the makeConnection createOrgKey and executeRemove methods It is a
434. rvletRequestWrapper or HttpServletRequestWrapper To override response methods you wrap the response in an object that extends ServletRe sponseWrapper or HttpServletResponseWrapper 67 68 JAVA SERVLET TECHNOLOGY HitCounterFilter wraps the response in a CharResponseWrapper The wrapped response is passed to the next object in the filter chain which is Book StoreServlet BookStoreServlet writes its response into the stream created by CharResponseWrapper When chain doFilter returns HitCounterFilter retrieves the servlet s response from PrintWriter and writes it to a buffer The filter inserts the value of the counter into the buffer resets the content length header of the response and finally writes the contents of the buffer to the response stream PrintWriter out response getWriterQ CharResponseWrapper wrapper new CharResponseWrapper CHttpServletResponse response chain doFilterC request wrapper CharArrayWriter caw new CharArrayWriterQ caw write wrapper toString substring Q wrapper toString indexOf lt body gt 1 caw write lt p gt n lt center gt messages getString Visitor lt font color red gt counter getCounter lt font gt lt center gt caw write n lt body gt lt htm1 gt response setContentLength caw toString length out write caw toString out close public class CharResponseWrapper extends HttpServletResponseWrapper private CharArrayWri
435. s Figure 2 2 Response The Hello application contains two Web components that generate the greeting and the response This tutorial has two versions of the application a servlet ver sion called Hellol in which the components are implemented by two servlet classes GreetingServlet java and ResponseServlet java and a JSP ver sion called Hello2 in which the components are implemented by two JSP pages greeting jsp and response jsp The two versions are used to illustrate the tasks involved in packaging deploying and running an application that contains Web components If you are viewing this tutorial online you must download the INTRODUCTION TO WEB APPLICATIONS tutorial bundle to get the source code for this example See About the Examples page ix Web Modules Web components and static Web content files such as images are called Web resources A Web module is the smallest deployable and usable unit of Web resources in a J2EE application A J2EE Web module corresponds to a Web application as defined in the Java Servlet Specification Web modules are typically packaged and deployed as Web archive WAR files The format of a WAR file is identical to that of a JAR file However the contents and use of WAR files differ from JAR files so WAR file names use a war exten sion In addition to Web components and Web resources a Web module can contain other files including e Server side utility classes database beans shoppi
436. s lt slide gt lt title gt This is the title lt title gt lt slide gt or as lt slide title This is the title gt lt slide gt 233 234 UNDERSTANDING XML In some cases the different characteristics of attributes and elements make it easy to choose Let s consider those cases first and then move on to the cases where the choice is more ambiguous Forced Choices Sometimes the choice between an attribute and an element is forced on you by the nature of attributes and elements Let s look at a few of those considerations The data contains substructures In this case the data item must be modeled as an element It can t be mod eled as an attribute because attributes take only simple strings So if the title can contain emphasized text like this The lt em gt Best lt em gt Choice then the title must be an element The data contains multiple lines Here it also makes sense to use an element Attributes need to be simple short strings or else they become unreadable if not unusable Multiple occurrences are possible Whenever an item can occur multiple times like paragraphs in an article it must be modeled as an element The element that contains it can only have one attribute of a particular kind but it can have many subelements of the same type The data changes frequently When the data will be frequently modified with an editor it may make sense to model it as an element Many XML aware editor
437. s scope application class MyLocales gt lt form name localeForm action index jsp method post gt lt b gt Locale lt b gt lt select name locale gt lt String selectedLocale request getParameter locale Iterator i locales getLocaleNames iterator while Ci hasNextQ String locale String i nextQ if CselectedLocale null amp amp selectedLocale equals locale gt lt option selected gt lt 1locale gt lt option gt else lt option gt lt 1ocale gt lt option gt F gt lt select gt lt input type submit name Submit value Get Date gt lt form gt lt jsp include page date jsp gt lt body gt lt html gt The source for the Duke s Bookstore application is located in the lt INSTALL gt j2eetutorial examples web date directory To build deploy and execute this JSP page 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web date 2 Expand the date node 3 Right click the WEB INF directory and choose Deploy JAVASERVER PAGES TECHNOLOGY 4 Right click the WEB INF directory and choose Execute You will see a combo box whose entries are locales Select a locale and click Get Date You will see the date expressed in a manner appropriate for that locale The Example J SP Pages To illustrate JSP technology this chapter rewrites each servlet in the Duke s Bookstore application introduced in The Example Servlets page 48
438. s HttpServilet private int serviceCounter Q Access methods for serviceCounter protected synchronized void enteringServiceMethod serviceCounter protected synchronized void leavingServiceMethod serviceCounter protected synchronized int numServices return serviceCounter The service method should increment the service counter each time the method is entered and should decrement the counter each time the method returns This is one of the few times that your HttpServlet subclass should override the ser vice method The new method should call super service to preserve all of the original service method s functionality protected void service HttpServletRequest req HttpServletResponse resp throws ServletException IOException enteringServiceMethod try super service req resp NOTIFYING METHODS TO SHUT DOWN 81 finally leavingServiceMethod Notifying Methods to Shut Down To ensure a clean shutdown your destroy method should not release any shared resources until all of the service requests have completed One part of doing this is to check the service counter Another part is to notify the long running meth ods that it is time to shut down For this notification another field is required The field should have the usual access methods public class ShutdownExample extends HttpServlet private boolean shuttingDown Access methods for shuttingDown protected syn
439. s directly from the sender to the destination usually a URL that the sender specifies The first step is to obtain a SOAPConnectionFactory object that you can use to create your connection The SAAJ API makes this easy by providing the SOAP ConnectionFactory class with a default implementation You can get an instance of this implementation with the following line of code SOAPConnectionFactory scFactory SOAPConnectionFactory newlInstance Notice that because newInstance is a static method you will always use the class name SOAPConnectionFactory when you invoke its newInstance method Now you can use scFactory to create a SOAPConnection object SOAPConnection con scFactory createConnection You will use con later to send the message that is created in the next part Creating a Message The next step is to create a message which you do using a MessageFactory object If you are a standalone client you can use the default implementation of the MessageFactory class that the SAAJ API provides The following code fragment illustrates getting an instance of this default message factory and then using it to create a message MessageFactory factory MessageFactory newlInstance SOAPMessage message factory createMessage As is true of the newInstance method for SOAPConnectionFactory the newIn stance method for MessageFactory is static so you invoke it by calling Mes sageFactory newlInstance Note that it is possible
440. s in business logic The code that implements the functionality of an application 431 ABCDEFGHIJKLMNOPQRSTUVWXYZ callback methods Component methods called by the container to notify the component of important events in its life cycle CDATA A predefined XML tag for Character DATA that means don t interpret these characters as opposed to Parsed Character Data PCDATA in which the normal rules of XML syntax apply for example angle brackets demarcate XML tags tags define XML elements etc CDATA sections are typically used to show examples of XML syntax certificate authority A trusted organization that issues public key certificates and provides identi fication to the bearer client certificate authentication An authentication mechanism that uses HTTP over SSL in which the server and optionally the client authenticate each other with a public key certifi cate that conforms to a standard that is defined by X 509 Public Key Infra structure PKI comment Text in an XML document that is ignored unless the parser is specifically told to recognize it content The part of an XML document that occurs after the prolog including the root element and everything it contains commit The point in a transaction when all updates to any resources involved in the transaction are made permanent component An application level software unit supported by a container Components are configurable at deployment time See also Web c
441. s make it easy modify element data while attributes can be somewhat harder to get to The data is a small simple string that rarely if ever changes This is data that can be modeled as an attribute However just because you can does not mean that you should Check the Stylistic Choices section next to be sure Using DTDs when the data is confined to a small number of fixed choices Here is one time when it really makes sense to use an attribute A DTD can prevent an attribute from taking on any value that is not in the preapproved list but it cannot similarly restrict an element With a schema on the other hand both attributes and elements can be restricted ATTRIBUTES AND ELEMENTS Stylistic Choices As often as not the choices are not as cut and dried as those shown above When the choice is not forced you need a sense of style to guide your thinking The question to answer then is what makes good XML style and why Defining a sense of style for XML is unfortunately as nebulous a business as defining style when it comes to art or music There are a few ways to approach it however The goal of this section is to give you some useful thoughts on the subject of XML style Visibility One heuristic for thinking about XML elements and attributes uses the con cept of visibility If the data is intended to be shown to be displayed to some end user then it should be modeled as an element On the other ha
442. s of using the JAXM APL In this section you will use some of those code fragments to create applications First you will see the program Request java Then you will see how to create and run the following applications e UddiPing java A simple standalone example that sends a message to a UDDI test registry and receives a response e SOAPFaultTest java A simple standalone example that shows how to specify SOAP faults 324 WEB SERVICES MESSAGING WITH JAXM e JAXM Simple A simple example of sending and receiving a message using the local provider e SAAJ Simple An application similar to the Simple example except that it is written using only the SAAJ API e JAXM Translator An application that uses a simple translation service to translate a given word into different languages e JAXM Tags An example that uses JavaServer Pages tags to generate and consume a SOAP message e JAXM Provider A simple example of a JAXM provider e JAXM Provider Administrator A simple web based administrative tool for the JAXM provider This list presents the sample applications according to what they do You can also look at the sample applications as examples of the three possible types of JAXM client e Those that do not use a messaging provider and also do not run in a container These are called standalone applications The samples UddiPing and SOAPFaultTest are examples of standalone clients Those that do not use a
443. s should be internationalized and localized it is particularly important for Web applications because of the far reaching nature of the Web For a good overview of internationalization and localization see http java sun com docs books tutorial il8n index htm There are two approaches to internationalizing a Web application e Provide a version of the JSP page in each of the target locales and have a controller servlet dispatch the request to the appropriate page depending on the requested locale This approach is useful if large amounts of data on a page or an entire Web application need to be internationalized e Isolate any locale sensitive data on a page such as error messages string literals or button labels into resource bundles and access the data so that the corresponding translated message is fetched automatically and inserted into the page Thus instead of creating strings directly in your code you create a resource bundle that contains translations and read the translations from that bundle using the corresponding key A resource bundle can be backed by a text file properties resource bundle or a class list resource bundle containing the mappings In the following chapters on Web technology the Duke s Bookstore example is internationalized and localized into English and Spanish The key and value pairs are contained in list resource bundles named mes sages BookMessage_ class To give you an idea of what the key a
444. s will illustrate some of the typical ways to add content Populating a Message Content can be added to the SOAPPart object to one or more AttachmentPart objects or to both parts of a message Populating the SOAP Part of a Message As stated earlier all messages have a SOAPPart object which has a SOAPEnve lope object containing a SOAPHeader object and a SOAPBody object One way to add content to the SOAP part of a message is to create a SOAPHeaderElement object or a SOAPBodyElement object and add an XML fragment that you build with the method SOAPElement addTextNode The first three lines of the follow ing code fragment access the SOAPBody object body which is used to create a new SOAPBodyElement object and add it to body The argument passed to the createName method is a Name object identifying the SOAPBodyElement being added The last line adds the XML string passed to the method addTextNode SOAPPart sp m getSOAPPart SOAPEnvelope envelope sp getSOAPEnvelope SOAPBody body envelope getSOAPBody SOAPBodyElement bodyElement body addBodyElement envelope createName text hotitems http hotitems com products gizmo bodyElement addTextNode some xml1 text POPULATING A MESSAGE Another way is to add content to the SOAPPart object by passing it a javax xml1 transform Source object which may be a SAXSource DOMSource or StreamSource object The Source object contains content for the SOAP part
445. saveOrganizations method which creates one or more new organizations in a registry if they did not exist previously If one of the organizations exists but some of the data have changed the saveOrganizations method updates and replaces the data MANAGING REGISTRY DATA After a client populates an organization with the information it wants to make public it saves the organization The registry returns the key in its response and the client retrieves it Add organization and submit to registry Retrieve key if successful Collection orgs new ArrayList orgs add org BulkResponse response blcm saveOrganizations orgs Collection exceptions response getException if exceptions null System out printInC Organization saved Collection keys response getCollection Iterator keyIter keys iterator if keyIter hasNextQ javax xml registry infomodel Key orgKey javax xml registry infomodel Key keyIter nextQ String id orgKey getIdQ System out printInC Organization key is id org setKey orgKey Removing Data from the Registry A registry allows you to remove from the registry any data that you have submit ted to it You use the key returned by the registry as an argument to one of the BusinessLifeCycleManager delete methods deleteOrganizations delete Services deleteServiceBindings and others The JAXRDelete sample program deletes the organization created by the JAXR Publish
446. se the namespace prefix followed by a colon and the particular construct to apply For example the following piece of style sheet indicates that the name data must be inserted into a row of an HTML table lt xsl template match name gt lt tr gt lt td gt lt xsl apply templates gt lt td gt lt tr gt lt xsl template gt The following style sheet specifies that the XML data is converted to HTML and that the coffee entries are inserted into a row in a table lt xsl istylesheet version 1 0 xmIns xsl http www w3 org 1999 XSL Transform gt lt xsl template match priceList gt lt htm1l gt lt head gt Coffee Prices lt head gt lt body gt lt table gt lt xsl apply templates gt lt table gt lt body gt lt html gt lt xsl template gt lt xsl template match name gt lt tr gt lt td gt lt xsl apply templates gt lt td gt lt tr gt lt xsl template gt lt xsl template match price gt lt tr gt lt td gt lt xsl apply templates gt lt td gt lt tr gt lt xsl template gt lt xsl stylesheet gt To perform the transformation you need to obtain an XSLT transformer and use it to apply the style sheet to the XML data The following code fragment obtains a transformer by instantiating a TransformerFactory object reading in the 250 INTRODUCTION TO WEB SERVICES style sheet and XML files creating a file for the HTML output and then finally obtaining the Transformer object transfo
447. searching a business registry for potential sources the business might get several WSDL documents one for each of the Web services that meets its search criteria The business client can use these WSDL documents to see what the ser vices offer and how to contact them Another important use for a WSDL document is as a basis for creating helper classes used by a client to communicate with a remote service and by the server to communicate with a remote client CREATING A WEB SERVICE A JAX RPC runtime system converts the client s remote method call into a SOAP message and sends it to the service as an HTTP request On the server side the JAX RPC runtime system receives the request translates the SOAP message into a method call and invokes it After the Web service has processed the request the runtime system goes through a similar set of steps to return the result to the client The point to remember is that as complex as the implementa tion details of communication between the client and server may be they are invisible to both Web services and their clients Creating a Web Service Developing a Web service using JAX RPC is surprisingly easy The service itself is basically two files an interface that declares the service s remote procedures and a class that implements those procedures There is a little more to it in that the service needs to be configured and deployed but first let s take a look at the two main components of a
448. service on localhost If you are running the service on a different host you need to update the service URLs To run the test programs in the IDE 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples cb jaxm 2 Right click TestPriceListRequest or TestOrderRequest and choose Execute Here is what you should see when you run the former Arabica 4 50 Espresso 5 00 Dorada 6 00 House Blend 5 00 DEPLOYING THE COFFEE BREAK SERVER Deploying the Coffee Break Server Server Configuration The Coffee Break Server accesses three services registry JAX RPC service JAXM service to build retail price lists and order coffee The information needed to access the services is stored in the file lt INSTALL gt examples cb cbservice CoffeeServices properties This file contains URLs and security parameters for accessing the registry the name under which the JAX RPC service is registered and the URLs for making requests on the JAXM service registryQuery url http localhost 8089 registry server RegistryServerServ let registryPublish url http localhost 8089 registry server RegistryServerServ let registry username testuser registry password testuser JAXRPCService name JAXRPCCoffeeDistributor JAXMPricelist url http localhost 80 jaxm coffee supplier getPriceList JAXMOrder url http localhost 80 jaxm coffee supplier orderCoffee Note The default configuration assumes that you are running the registry server
449. ses new ArrayList postalAddresses add postAddr primaryContact setPostalAddresses postalAddresses A JAXR query can then retrieve the postal address using PostalAddress meth ods if the postal address scheme and semantic equivalences for the query are the same as those specified for the publication To retrieve postal addresses when you do not know what postal address scheme was used to publish them you can retrieve them as a collection of Slot objects The JAXRQueryPostal java sam ple program shows how to do this In general you can create a user defined postal address taxonomy for any post alAddress tModels that use the well known categorization in the uddi org types taxonomy which has the tModel UUID uuid clacf26d 9672 4404 9d70 39b756e62ab4 with a value of postalAddress You can retrieve the tModel overviewDoc which points to the technical detail for the specification of the scheme where the taxonomy structure definition can be found The JAXR equivalent of an overviewDoc is an ExternalLink Running the Client Examples The simple client programs provided with this tutorial can be run from the com mand line You can modify them to suit your needs They allow you to specify the IBM registry the Microsoft registry or the Registry Server for queries and updates you can specify any other UDDI version 2 registry 372 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR The client examples in the lt INSTALL gt j2eetu
450. sh The Web module will be mounted as a filesystem in the IDE Expand the filesys tem and the WEB INF node to view the Web module structure If you click on the web xml file you can view the deployment properties associated with the Web module To view the Hellol Web module 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web hel1lol 2 Expand the nodes he1101 WEB INF Creating a Web Component You create a Web component in the context of a Web module To create a Web component in the IDE 1 Mount the Web module as a filesystem 2 Expand the module and WEB INF nodes 3 To create a JSP page right click the module node and choose New gt JSP amp Servlet JSP or Servlet 4 To create a servlet right click the classes node and choose New gt JSP amp Servlet Servlet 5 Type a name for the JSP page or servlet 6 Click Finish 30 INTRODUCTION TO WEB APPLICATIONS Configuring Web Modules Web applications are configured via elements contained in the Web application deployment descriptor The IDE generates the descriptor when you create a Web module and adds elements when you create Web components and associated classes You can modify the elements via the property sheets associated with the descriptor The following sections give a brief introduction to the Web application features you will usually want to configure A number of security parameters can be specified these are covered
451. show gt es ideshow gt This tag defines the slideshow element as the root element for the document An XML document must have exactly one root element This is where that ele ment is specified In other words this tag identifies the document content as a slideshow The DOCTYPE tag occurs after the XML declaration and before the root element The SYSTEM identifier specifies the location of the DTD file Since it does not start with a prefix like http or file the path is relative to the location of the XML document Remember the setDocumentLocator method The parser is using that information to find the DTD file just as your application would to find a file relative to the XML document A PUBLIC identifier could also be used to specify the DTD file using a unique name but the parser would have to be able to resolve it The DOocTyPE specification could also contain DTD definitions within the XML document rather than referring to an external DTD file Such definitions would be contained in square brackets like this lt DOCTYPE slideshow SYSTEM slideshowl dtd local subset definitions here gt Yov ll take advantage of that facility in a moment to define some entities that can be used in the document 216 UNDERSTANDING XML Documents and Data Earlier you learned that one reason you hear about XML documents on the one hand and XML data on the other is that XML handles both comfortably depending on wheth
452. sing a parameter entity in slideshow3 dtd without conflict Intoduction to Web Services Maydene Fisher Wis services in the general meaning of the term are services offered via the Web In a typical Web services scenario a business application sends a request to a service at a given URL using the SOAP protocol over HTTP The service receives the request processes it and returns a response An often cited example of a Web service is that of a stock quote service in which the request asks for the current price of a specified stock and the response gives the stock price This is one of the simplest forms of a Web service in that the request is filled almost immediately with the request and response being parts of the same method call Another example could be a service that maps out an efficient route for the deliv ery of goods In this case a business sends a request containing the delivery des tinations which the service processes to determine the most cost effective delivery route The time it takes to return the response depends on the complex ity of the routing so the response will probably be sent as an operation that is separate from the request Web services and consumers of Web services are typically businesses making Web services predominantly business to business B to B transactions An enterprise can be the provider of Web services and also the consumer of other Web services For example a wholesale distributo
453. so seen how to get the content from a reply message This knowledge was applied in writing and run ning the UddiPing and SOAPFaultTest examples You have also learned how to deploy simple JAXM examples in a J2EE server In addition the case study The Coffee Break Application page 383 provides detailed examples of JAXM code for both the client and server You now have first hand experience of how JAXM makes it easier to do XML messaging 346 WEB SERVICES MESSAGING WITH JAXM Further Information You can find additional information about JAXM from the following e Documents bundled with the JAXM Reference Implementation at lt S1STUDIO_HOME gt jwsdp docs jaxm e SAAJ 1 1 specification available from http java sun com xml downloads saaj htm e JAXM 1 1 specification available from http java sun com xml downloads jaxm htm e JAXM website at http java sun com xm1 jaxm 11 Publishing and Disc overng Web Servic es with J AXR Kim Haase Tue Java API for XML Registries JAXR provides a uniform and standard Java API for accessing different kinds of XML registries After providing a brief overview of JAXR this chapter describes how to imple ment a JAXR client to publish an organization and its web services to a registry and to query a registry to find organizations and services Finally it explains how to run the examples provided with this tutorial and offers links to more informa tion on JAXR Overvie
454. sponse that the application server will return to the method cal11 now contains the headers that were in the original request static void putHeaders MimeHeaders headers HttpServletResponse res Iterator it headers getAllHeadersQ while Cit hasNext MimeHeader header MimeHeader it nextQ String values headers getHeader header getName if C values length 1 res setHeader header getName header getValue else StringBuffer concat new StringBufferQ int i Q while i lt values length if G 0 concat append concat append values i res setHeader header getName concat toString The method onMessage is the application code for responding to the message sent by PriceListRequest and internalized into msg It uses the static Message Factory object fac to create the SOAPMessage object message and then popu lates it with the distributor s current coffee prices The method doPost invokes onMessage and passes it msg In this case onMes sage does not need to use msg because it simply creates a message containing the distributor s price list The onMessage method in ConfirmationServlet Returning the Order Confirmation page 400 on the other hand uses the mes sage passed to it to get the order ID public SOAPMessage onMessage SOAPMessage msg SOAPMessage message null try message fac createMessage SOAPPart part message getSOAPPart SOAPEnvelo
455. ssages e The client can act in the client role only It follows that if you want to provide a Web service that is able to get and save requests that are sent to you at any time you must use a messaging provider You will also need to run in a container which provides the messaging infrastructure used by the provider A messaging provider gives you the flexibility to assume both the client and service roles and it also lets you send one way messages In addition if your messaging provider supports a protocol such as ebXML or SOAP RP on top of SOAP you can take advantage of the additional quality of service features that it provides Messaging with and withouta Provider JAXM clients can be categorized according to whether or not they use a messag ing provider Those that do not use a messaging provider can be further divided into those that run in a container and those that do not A JAXM client that does not use a messaging provider and also does not run in a container is called a standalone client 301 302 WEB SERVICES MESSAGING WITH JAXM Tutonal This section will walk you through the basics of sending a SOAP message using the JAXM API At the end of this chapter you will know how to do the follow ing e Get a connection e Create a message e Add content to a message e Send a message e Retrieve the content from a response message e Create and retrieve a SOAP fault element First we ll walk through the steps in se
456. standard in con junction with the MIME data types defined for electronic messaging attach ments together provide a much more useful understandable and extensible mechanism for referencing unparsed external entities Note The XML described here is in s1ideshow1b dtd It shows how binary refer ences can be made assuming that the application which will be processing the XML data knows how to handle such references To set up the slideshow to use image files add the text highlighted below to your slideshow1b dtd file lt ELEMENT slide Cimage title item gt lt ATTLIST slide type tech exec all IMPLIED gt lt ELEMENT title C PCDATA gt lt ELEMENT item PCDATA item gt lt ELEMENT image EMPTY gt lt ATTLIST image alt CDATA IMPLIED src CDATA REQUIRED type CDATA image gif gt These modifications declare image as an optional element in a slide define it as empty element and define the attributes it requires The image tag is patterned after the HTML 4 0 tag img with the addition of an image type specifier type The img tag is defined in the HTML 4 0 Specification 223 224 UNDERSTANDING XML The image tag s attributes are defined by the ATTLIST entry The alt attribute which defines alternate text to display in case the image can t be found accepts character data CDATA It has an implied value which means that it is optional and that the program processing the data kno
457. stem out printInC The price of Mocha Java is inMochaJava false inPrice false s Once the parser has come to the Mocha Java coffee element here is the relevant state after the following method calls next invocation of startElement inName is true next invocation of characters inMochaJava is true next invocation of startElement inPrice is true next invocation of characters prints price The SAX parser can perform validation while it is parsing XML data which means that it checks that the data follows the rules specified in the XML docu ment s schema A SAX parser will be validating if it is created by a SAX ParserFactory object that has had validation turned on This is done for the SAXParserFactory object factory in the following line of code factory setValidating true THE DOM API So that the parser knows which schema to use for validation the XML document must refer to the schema in its DOCTYPE declaration The schema for the price list is priceList DTD so the DOCTYPE declaration should be similar to this lt DOCTYPE PriceList SYSTEM priceList DTD gt The DOM API The Document Object Model DOM defined by the W3C DOM Working Group is a set of interfaces for building an object representation in the form of a tree of a parsed XML document Once you build the DOM you can manipulate it with DOM methods such as insert and remove just as you would manipulate any other tree data str
458. stom tag is a user defined JSP language element When a JSP page contain ing a custom tag is translated into a servlet the tag is converted to operations on an object called a tag handler The Web container then invokes those operations when the JSP page s servlet is executed Custom tags have a rich set of features They can e Be customized via attributes passed from the calling page e Access all the objects available to JSP pages e Modify the response generated by the calling page e Communicate with each other You can create and initialize a JavaBeans component create a variable that refers to that bean in one tag and then use the bean in another tag e Be nested within one another allowing for complex interactions within a JSP page The Example J SP Pages This chapter describes the tasks involved in using and defining tags The chapter illustrates the tasks with excerpts from the JSP version of the Duke s Bookstore application discussed in The Example JSP Pages page 86 rewritten to take advantage of two tag libraries Struts and template The third section in the chap ter Examples page 137 describes two tags in detail an iterator tag and the set of tags in the template tag library THE EXAMPLE JSP PAGES The Struts tag library provides a framework for building internationalized Web applications that implement the Model View Controller design pattern Struts includes a comprehensive set of utility custom tags for ha
459. sun xml registry http proxyHost Specifies the HTTP proxy host to be used for access ing external registries com sun xml registry http proxyPort Specifies the HTTP proxy port to be used for access ing external registries usually 8080 com sun xml registry https proxyHost Same as HTTP proxy Specifies the HTTPS proxy host to be used for host value accessing external registries com sun xml registry https proxyPort Same as HTTP proxy Specifies the HTTPS proxy port to be used for port value accessing external registries usually 8080 ESTABLISHING A CONNECTION 355 Table 11 2 Implementation Specific JAXR Connection Properties Property Name and Description Default Value com sun xml registry http proxyUserName Specifies the user name for the proxy host for HTTP proxy authentication if one is required com sun xml registry http proxyPassword Specifies the password for the proxy host for HTTP proxy authentication if one is required com sun xml registry useCache Boolean Tells the JAXR implementation to look for registry passed in objects in the cache first and then to look in the regis as String try if not found com sun xml registry useSOAP Tells the JAXR implementation to use Apache SOAP rather than the Java API for XML Messaging may be useful for debugging You must install Apache SOAP downloadable from the Apache web site http xml apache org in order to use this option Boolean
460. t public void doPost HttpServletRequest request HttpServletResponse response throws ServletException IOException PrintWriter out response getWriterQ out printInC lt body bgcolor FFFFFF gt lt center gt lt hr gt lt br gt amp nbsp lt h1 gt lt font size 3 color CCQ066 gt Duke s lt font gt lt img src request getContextPath duke books gif gt 73 74 JAVA SERVLET TECHNOLOGY lt font size 3 color black gt Bookstore lt font gt lt hi gt lt center gt lt br gt amp nbsp lt hr gt lt br gt Each servlet in the Duke s Bookstore application includes the result from Ban nerServlet with the following code RequestDispatcher dispatcher getServletContext getRequestDispatcher banner if dispatcher null dispatcher include request response Transfering Control to Another Web Component In some applications you might want to have one Web component do prelimi nary processing of a request and have another component generate the response For example you might want to partially process a request and then transfer to another component depending on the nature of the request To transfer control to another Web component you invoke the forward method of a RequestDispatcher When a request is forwarded the request URL is set to the path of the forwarded page If the original URL is required for an
461. t HTTP Request Template JSP ECE 3 ge T o l HttpServlet atalog Response ane BookDB HTTP Response Figure 5 1 Request Flow Through Duke s Bookstore Components The template tag library files are located in the directory lt INSTALL gt j2eetutorial examples web template The classes are packaged into a JAR and already included in the WEB INF 1ib directory of all successive versions of the Duke s Bookstore example To recreate the template library JAR 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web temp late 2 Right click the template node and choose Compile 3 Expand the template node 4 Create the template JAR a Right click the template TLD and choose Create Tag Library JAR b Right click the template JAR recipe node and choose Compile 5 Expand the template JAR recipe node The source for the Duke s Bookstore application is located in the lt INSTALL gt j2eetutorial examples web bookstore3 directory THE EXAMPLE JSP PAGES 117 To deploy and run the example 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstore3 2 Expand the bookstore3 node 5 Right click the WEB INF directory and choose Deploy Set up the PointBase database as described in Accessing Databases from Web Applications page 39 Open the bookstore URL http localhost 80 bookstore3 enter To review the deployment settings A U
462. t The data for the bookstore application is maintained in a database and accessed through the helper class database BookDB The database package also contains the class BookDetails which represents a book The shopping cart and shop ping cart items are represented by the classes cart ShoppingCart and cart ShoppingCartItem respectively The source for the Duke s Bookstore application is located in the lt INSTALL gt j2eetutorial examples web bookstorel directory created when you unzip the tutorial bundle see About the Examples page ix To deploy and run the example 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstorel 2 Expand the bookstore1 node 3 Right click the WEB INF directory and choose Deploy 4 Set up the PointBase database as described in Accessing Databases from Web Applications page 39 5 Open the bookstore URL http localhost 80 bookstore1 enter To review the deployment settings 1 Expand the WEB INF node 2 Select the web xm1 file 3 Select the Deployment property sheet 4 Browse the error page mappings a Click the Error Pages property and open the property editor b Notice that two HTTP status codes 404 and 500 and four exceptions are mapped to the error page errorpage htm1 5 Browse the filter property and mappings a Click the Filters property and open the property editor 49 50 JAVA SERVLET TECHNOLOGY b Notice that the filters classes are filt
463. t Market Size lt predicted You see an angle bracket lt where you coded amp lt because the XML parser converts the reference into the entity it represents and passes that entity to the application Handling Text with XML Style Syntax When you are handling large blocks of XML or HTML that include many of the special characters it would be inconvenient to replace each of them with the appropriate entity reference For those situations you can use a CDATA section Note The results of the modifications below are contained in s1ideSamp1e04 xm1 A CDATA section works like lt pre gt lt pre gt in HTML only more so all whitespace in a CDATA section is significant and characters in it are not inter preted as XML A CDATA section starts with lt CDATA and ends with gt 209 210 UNDERSTANDING XML Add the text highlighted below to your slideSample xm1 file to define a CDATA section for a fictitious technical slide and save a copy of the file as slideSamp1eQ4 xm1 lt slide type tech gt lt title gt How it Works lt title gt lt item gt First we fozzle the frobmorten lt item gt lt item gt Then we framboze the staten lt item gt lt item gt Finally we frenzle the fuznaten lt item gt lt item gt lt CDATA Diagram frobmorten lt fuznaten lt 3 gt A lt l gt lt l gt fozzle V lt 2 gt framboze Staten lt 3 gt frenzle lt 2 gt
464. t Enterprise Enterprise Container Bean Bean EJB Container Figure 1 5 J2EE Server and Containers J2EE server The runtime portion of a J2EE product A J2EE server provides EJB and Web containers Enterprise JavaBeans EJB container Manages the execution of enterprise beans for J2EE applications Enterprise beans and their container run on the J2EE server Web container Manages the execution of JSP page and servlet components for J2EE appli cations Web components and their container run on the J2EE server Application client container Manages the execution of application client components Application clients and their container run on the client Applet container Manages the execution of applets Consists of a Web browser and Java Plug in running on the client together Packaging A J2EE application is delivered in an Enterprise Archive EAR file An EAR file is a standard Java Archive JAR file with an ear extension The EAR file 14 OVERVIEW contains J2EE modules Using EAR files and modules makes it possible to assemble a number of different J2EE applications using some of the same com ponents No extra coding is needed it is just a matter of assembling various J2EE modules into J2EE EAR files A J2EE module consists of one or more J2EE components for the same con tainer type and one component deployment descriptor of that type A deployment descriptor is an XML document with an xm1 extension that describes a
465. t again later without any changes In the previous example however you would need to add the missing information before sending the message again A SOAPFau1t object contains the following elements e A fault code always required The SOAP 1 1 specification defines a set of fault code values in section 4 4 1 which a developer may extend to cover other problems The default fault codes defined in the specification relate to the JAXM API as follows e VersionMismatch the namespace for a SOAPEnvelope object was invalid e MustUnderstand an immediate child element of a SOAPHeader object had its mustUnderstand attribute set to 1 and the processing party did not understand the element or did not obey it e Client the SOAPMessage object was not formed correctly or did not contain the information needed to succeed e Server the SOAPMessage object could not be processed because of a processing error not because of a problem with the message itself e A fault string always required A human readable explanation of the fault e A fault actor required if the SOAPHeader object contains one or more actor attributes optional if no actors are specified meaning that the only actor is the ultimate destination The fault actor which is specified as a URI identifies who caused the fault For an explanation of what an actor is see the section Intermediate Destinations page 300 e A Detail object required if the
466. t and then specify the semantic equivalences between the concepts in the UDDI format classification scheme and the com ments in the JAXR PostalAddress classification scheme The JAXR PostalAd dress classification scheme is provided by the implementation of JAXR in the Sun ONE Application Server In the JAXR API a PostalAddress object has the fields streetNumber street city state postalCode and country 369 370 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR To specify the mapping between the JAXR postal address format and another format you need to set two connection properties e The javax xml registry postalAddressScheme property which spec ifies a postal address classification scheme for the connection e The javax xml registry semanticEquivalences property which specifies the semantic equivalences between the JAXR format and the other format For example suppose you want to use a scheme that has been published to the IBM registry and that has the UUID uuid 6eaf4b50 4196 11d6 9e2b 000629dcQa2b In the implementation of JAXR in the Sun ONE Application Server you first use the system property com sun xm1 registry userTaxonomyFilenames to spec ify the concepts file where the scheme is described Next you specify the postal address scheme using the id value from the JAXR ClassificationScheme element the UUID Case does not matter props setProperty javax xml registry postalAddressScheme uuid 6eaf4b50 4196
467. t editor right click and choose Validate XML from the menu you will see an error message about a missing DTD file Ignore this error message 2 In order to run the JAXM Provider Administrator example using the Sun ONE Application Server you need to change the security properties for the web xml file as follows a Expand the WEB INF node if you have not already done so b Click the web xm1 file c In the property window for the file click the Security tab You will see that the Security Constraints field contains the text 1 Security Con straint Click this field then click the ellipsis d In the Property Editor select the security constraint and click Remove e Click OK 3 Specify the following context root for the web module jaxm provideradmin 4 Right click the WEB INF node and choose Deploy from the menu 5 Right click the WEB INF node and choose Execute from the menu If this doesn t work open a web browser and enter the following URL localhost 80 jaxm provideradmin The JAXM Provider Administration Tool appears Expand the nodes in the left window to see what you can do in the tool See the next section for more infor mation CONCLUSION 345 Using the J AXM Provider Administration Tool The Provider Administration tool is a convenient means of configuring a mes saging provider A messaging provider a third party service handles the behind the scenes details of the routing and transmissio
468. t em gt buys lt em gt WonderWidgets lt item gt lt slide gt lt slideshow gt Note that defining a title element conflicts with the XHTML element that uses the same name We ll discuss the mechanism that produces the conflict the DTD along with possible solutions later on in this tutorial Adding an Empty Hement One major difference between HTML and XML though is that all XML must be well formed which means that every tag must have an ending tag or be an empty tag You re getting pretty comfortable with ending tags by now Add the text highlighted below to define an empty list item element with no contents lt OVERVIEW gt lt slide type al1 gt lt title gt Overview lt title gt lt item gt Why lt em gt WonderWidgets lt em gt are great lt item gt lt item gt lt item gt Who lt em gt buys lt em gt WonderWidgets lt item gt lt slide gt lt slideshow gt Note that any element can be empty element All it takes is ending the tag with gt instead of gt You could do the same thing by entering lt item gt lt item gt which is equivalent 204 UNDERSTANDING XML Note Another factor that makes an XML file well formed is proper nesting So lt b gt lt i gt some_text lt i gt lt b gt is well formed because the lt i gt lt i gt sequence is completely nested within the lt b gt lt b gt tag This sequence on the other hand is not well formed lt b gt lt i
469. t in a JSP Page 98 Transferring Control to Another Web Component 100 Including an Applet 100 JavaBeans Components in JSP Pages 103 Extending the JSP Language 111 Further Information 112 Custom Tags in SP Pages 0000s0002sL13 What Is a Custom Tag 114 The Example JSP Pages 114 Using Tags 118 Defining Tags 122 Examples 137 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 CONTENTS JavaServer Pages Standard Tag Library 149 The Example JSP Pages 150 Using JSTL 151 Expression Language Support 153 Core Tags 159 XML Tags 165 Internationalization Tags 169 SQL Tags 172 Further Information 176 Understanding XML 0 0 eeeceeeeeeeees 177 Introduction to XML 177 XML and Related Specs Digesting the Alphabet Soup 187 Generating XML Data 199 Designing an XML Data Structure 233 Introduction to Web Services 0000020002 239 The Role of XML and the Java Platform 240 Overview of the Java APIs for XML 241 JAXP 242 JAX RPC 250 JAXM 256 JAXR 263 Sample Scenario 265 Building Web Services With J AX RPC 269 Types Supported By JAX RPC 270 Creating a Web Service with JAX RPC 272 Creating Web Service Clients with JAX RPC 276 Further Information 286 Web Services Messaging with J AXM 289 The Structure of the JAXM API 290 Overview of JAXM 291 Tutorial 302 Code Examples 323 Conclusion 345 vi Chapter 11 347 Chapter 12 Appendix A Appendix B CONTENTS
470. t name gt Oracle Corporation lt name gt lt description xml lang en gt Oracle Corporation provides the software and services for e business lt description gt lt serviceInfos gt lt serviceInfo serviceKey 4EDB6FCO 82AB 11D5 A4A5 0004AC49CC1E businessKey 2ACAA2D0 82A7 11D5 A4A5 0004AC49CC1E gt lt name gt E Business Network lt name gt lt servicelInfo gt lt serviceInfo serviceKey 3AD5A9BQ 82AA 11D5 A4A5 0004AC49CC1E businessKey 2ACAA2D0 82A7 11D5 A4A5 Q004AC49CC1E gt lt name gt Oracle Store lt name gt lt serviceInfo gt lt servicelInfo serviceKey 0735C300 82AB 11D5 A4A5 0004AC49CC1E businessKey 2ACAA2D0 82A7 11D5 A4A5 0004AC49CC1E gt lt name gt Oracle Technology Network lt name gt lt serviceInfo gt lt serviceInfo serviceKey 82757F80 82A9 11D5 A4A5 0004AC49CCI1E businessKey 2ACAA2D0 82A7 11D5 A4A5 0004AC49CC1E gt lt name gt Oracle com lt name gt lt serviceInfo gt lt serviceInfos gt lt businessInfo gt lt businessiInfos gt lt businessList gt lt Body gt lt Envelope gt The following output appears after the full XML message Content extracted from the reply message Oracle oracle powers the internet Oracle Corporation Oracle Corporation provides the software and services for e business There may be some occurrences of null in the output 336 WEB SERVICES MESSAGING WITH JAXM Running the program with Microsoft as the business name property instead of Oracle produces the foll
471. t newFault to retrieve the Detail object newDetail and then it uses newDetail to call the method getDetailEntries This method returns the java util Iterator object it which contains all of the DetailEntry objects in newDetail Not all SOAPFault objects are required to have a Detail object so the code tests to see whether newDetail is nu11 If it is not the code prints out the values of the DetailEntry object s as long as there are any Detail newDetail newFault getDetailQ if C newDetail null Iterator it newDetail getDetailEntriesQ while it hasNextQ DetailEntry entry DetailEntry it nextQ String value entry getValueQ System out printIn Detail entry value In summary you have seen how to add a SOAPFau1t object and its contents to a message as well as how to retrieve the information in a SOAPFault object A SOAPFault object which is optional is added to the SOAPBody object to convey status or error information It must always have a fault code and a String expla nation of the fault A SOAPFau1t object must indicate the actor that is the source of the fault only when there are multiple actors otherwise it is optional Simi larly the SOAPFault object must contain a Detail object with one or more DetailEntry objects only when the contents of the SOAPBody object could not be processed successfully Code Examples The first part of this tutorial used code fragments to walk you through the funda mental
472. t slightly less flexible 133 134 CUSTOM TAGS IN JSP PAGES Scripting Variable Properties A scripting variable has a names The name can be specified either as a constant or via the name of an attribute whose translation time value specifies the name of the variable The following scripting variable properties are optional e The fully qualified constant name of the class of the variable java lang String is the default e Whether the variable refers to a new object True is the default e The scope of the scripting variable defined NESTED is the default Table 5 5 describes the availability of the scripting variable and the methods where the value of the variable must be set or reset Table 5 5 Scripting Variable Availability Vae Availability Methods Between the start In doInitBody and doAfterBody for a tag handler tag and the end tag implementing BodyTag otherwise in doStartTag NESTED From the start tag In doInitBody doAfterBody and doEndTag for a AT_BEGIN until the end of the tag handler implementing BodyTag otherwise in page doStartTag and doEndTag After the end tag until the end of the In doEndTag page TagExtralnfo Class You can also define a tag extra info class by extending the class javax serv let jsp TagExtraInfo A TagExtraInfo must implement the getVari ableInfo method to return an array of VariableInfo objects containing the following information e Variable name e Variable
473. t step is to get a connection factory but in this case it is a ProviderConnectionFactory object You can obtain a ProviderConnectionFactory object by retrieving it from a naming service This is possible when your application is using a messaging provider and is deployed in a servlet container or J2EE server With a ProviderConnec tionFactory object you can create a connection to a particular messaging pro vider and thus be able to use the capabilities of a profile that the messaging provider supports To get a ProviderConnectionFactory object you first supply the logical name of your messaging provider to the container at deployment time This is the name associated with your messaging provider that has been registered with a naming service based on the Java Naming and Directory Interface JNDI API You can then do a lookup using this name to obtain a ProviderConnec tionFactory object that will create connections to your messaging provider For example if the name registered for your messaging provider is ProviderABC you can do a lookup on ProviderABC to get a ProviderConnectionFactory object and use it to create a connection to your messaging provider This is what is done in the following code fragment The first two lines use methods from the JNDI API to retrieve the ProviderConnectionFactory object and the last line uses a method from the JAXM API to create the connection to the messaging provider Note that because the JND
474. t that has the headers and content of the original request mes sage public class PriceListServlet extends HttpServlet MessageFactory msgFactory Every servlet has an init method This init method initializes the servlet with the configuration information that the application server passed to it Then it simply initializes msgFactory with the default implementation of the Message Factory class public void init ServletConfig servletConfig throws ServletException super init servletConfig try Initialize it to the default msgFactory MessageFactory newInstance catch CSOAPException ex throw new ServletException Unable to create message factory ex getMessage The next method defined in PriceListServlet is doPost which does the real work of the servlet by calling the onMessage method The onMessage method is discussed later in this section the application server passes the doPost method two arguments The first argument the HttpServletRequest object req holds the content of the message sent in PriceListRequest The doPost method gets the content from req and puts it in the SOAPMessage object msg so that it can pass it to the onMessage method The second argument the HttpServletRe sponse object resp will hold the message generated by executing the method onMessage 395 396 THE COFFEE BREAK APPLICATION In the following code fragment doPost calls the methods getHeaders and put Head
475. t the filesystem lt INSTALL gt j2eetutorial examples web iterator 2 Expand the iterator node 3 Right click the WEB INF directory and choose Deploy 4 Right click the WEB INF directory and choose Execute Your browser should display the page shown in Figure 5 2 lt Departments Netscape http localhostiterator index jsp gi al Departments Engineering Marketing Sales Figure 5 2 List of Departments J SP Page The list jsp page of the iterator example uses the iterator tag to step though a collection of department members First the collection is retrieved by a name specified as a request parameter The collection is supplied to the iterator tag which sets the scripting variable named member to each item in the collec tion Finally properties of the member variable are retrieved with jsp getProp erty statements for display in a table lt jsp useBean id org class org Organization gt lt String deptName String request getParameter deptName org Department dept org getDepartment deptName gt lt head gt lt title gt lt deptName gt Department lt title gt AN ITERATION TAG 139 lt head gt lt body bgcolor white gt lt table border 2 cellspacing 3 cellpadding 3 gt lt tr gt lt td colspan 3 gt lt b gt lt center gt lt deptName gt lt b gt lt center gt lt td gt lt tr gt lt tr gt lt td width 100 gt lt b gt Name lt b gt lt td gt lt td width
476. t you single source a DTD that you can use for multiple purposes If the number of conditional sections gets large though the result can be a complex document that is difficult to edit 237 238 UNDERSTANDING XML Summary Congratulations You have now created a number of XML files that you can use for testing purposes Here s a table that describes the files you have constructed Table 7 5 Listing of Sample XML Files slideSampleQ1 xm A basic file containing a few elements and attributes as well as comments slideSamp1eQ2 xm1 Includes a processing instruction SlideSamp1eBad1 xml A file that is not well formed slideSamp1eQ3 xm1 Includes a simple entity reference amp lt slideSamp1e04 xml Contains a CDATA section slideSamp1eQ5 xm1 References either a simple external DTD for elements slideshowla dtd for use with a nonvalidating parser or else a DTD that defines attributes s 1ideshow1b dtd for use with a validating parser slideSamp1eQ6 Defines two entities locally product and products and refer ences slideshow1b dtd slideSample0 7 References an external entity defined locally copy right xml and references s1ideshow1b dtd slideSamp1eQ8 References xhtm1 dtd using a parameter entity in slideshow2 dtd producing a naming conflict since title is declared in both slideSamp1eQ9 xm Changes the title element to slide title so it can refer ence xhtm1 dtd u
477. tains a SOAPPart object so you use message to retrieve it SOAPPart soapPart message getSOAPPartQ Next you can use soapPart to retrieve the SOAPEnvelope object that it contains SOAPEnvelope envelope soapPart getEnvelope You can now use envelope to retrieve its empty SOAPHeader and SOAPBody objects SOAPHeader header envelope getHeader SOAPBody body envelope getBodyQ Our example of a standalone client does not use a SOAP header so you can delete it Because all SOAPElement objects including SOAPHeader objects are derived from the Node interface you use the method Node detachNode to delete header header detachNode CLIENT WITHOUT A MESSAGING PROVIDER Adding Contentto the Body To add content to the body you need to create a SOAPBodyE lement object to hold the content When you create any new element you also need to create an asso ciated Name object to identify it One way to create Name objects is by using SOAPEnve lope methods so you can use envelope from the previous code frag ment to create the Name object for your new element Note The SAAJ API augments the javax xml soap package by adding the SOAPFactory class which lets you create Name objects without using a SOAPEn ve lope object This capability is useful for creating XML elements when you are not creating an entire message For example JAX RPC implementations find this ability useful When you are not working with a SOAPMessage object y
478. te it in simple ways without having to use 153 154 JAVASERVER PAGES STANDARD TAG LIBRARY scriptlets or request time expressions Currently a page author has to use an expression lt aName gt to access the value of a system or user defined Java Beans component For example lt x aTag att lt pageContext getAttribute aName gt gt Referring to nested bean properties is even more complex lt aName getFoo getBar Q gt This makes page authoring more complicated than it need be An expression language allows a page author to access an object using a simpli fied syntax such as lt x atag att aName gt for a simple variable or lt xialag att aName foo bar gt for a nested property The JSTL expression language promotes JSP scoped attributes as the standard way to communicate information from business logic to JSP pages For example the test attribute of the this conditional tag is supplied with an expression that compares the number of items in the session scoped attribute named cart with 0 lt c if test sessionScope cart numberOfItems gt Q gt lt c if gt The next version of the JSP specification will standardize on an expression lan guage for all custom tag libraries This release of JSTL includes a snapshot of that expression language Twin Libraries The JSTL tag libraries come in two versions which differ only in the way they support the use of runtime expressions for attr
479. tent Creates body content and adds to the tag handler e doInitBody Called before evaluation of the tag body e doAfterBody Called after evaluation of the tag body A typical invocation sequence is t doStartTagQ out pageContext pushBody t setBodyContent out perform any initialization needed after body content is set t doInitBodyQ t doAfterBody while doAfterBody returns EVAL_BODY_BUFFERED we iterate body evaluation t doAfterBody t doEndTag Q t pageContext popBody t releaseQ 148 CUSTOM TAGS IN JSP PAGES 6 JavaServer Pages Standard Tag Library Stephanie Bodoff Tue JavaServer Pages Standard Tag Library JSTL encapsulates core func tionality common to many JSP applications For example instead of iterating over lists using a scriptlet or different iteration tags from numerous vendors JSTL defines a standard tag that works the same everywhere This standardiza tion lets you learn a single tag and use it on multiple JSP containers Also when tags are standard containers can optimize their implementation JSTL has support for common structural tasks such as iteration and condition als tags for manipulating XML documents internationalization tags and tags for accessing databases using SQL It also introduces the concept of an expres sion language to simplify page development JSTL also provides a framework for integrating existing tag libraries with JSTL This chap
480. ter demonstrates the JSTL through excerpts from the JSP version of the Duke s Bookstore application discussed in previous chapters It assumes that you are familiar with the material in the Using Tags page 118 section of Chap ter 5 149 150 JAVASERVER PAGES STANDARD TAG LIBRARY The Example J SP Pages This chapter illustrates JSTL with excerpts from the JSP version of the Duke s Bookstore application discussed in Chapter 5 rewritten as follows The The Struts logic tags were replaced with JSTL core tags The scriptlets accessing a message store were replaced with message for matting tags The JavaBeans component database helper object was replaced with direct calls to the database via the JSTL SQL tags For most applications it is bet ter to encapsulate calls to a database in a bean JSTL includes SQL tags for situations where a new application is being prototyped and the overhead of creating a bean may not be warranted source for the Duke s Bookstore application is located in the lt INSTALL gt j2eetutorial examples web bookstore4 directory created when you unzip the tutorial bundle see About the Examples page ix To deploy and run the example 1 5 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstore4 Expand the bookstore4 node Right click the WEB INF directory and choose Deploy Set up the PointBase database as described in Accessing Databases from Web
481. ter output public String toString return output toStringQ public CharResponseWrapper HttpServletResponse response super response output new CharArrayWriterQ public PrintWriter getWriterQ return new PrintWriter output CREATING A FILTER 69 Figure 3 3 shows the entry page for Duke s Bookstore with the hit counter hip localhost8000 bookstorel enter lt aig Duke s A Bookstore What We re Reading In Web Components for Web Developers author Webster Masterson a world renowned guru on web development talks about how web components can transform the way you develop applications for the web This is a must read for any self respecting web developer Start Shopping You are visitor number 4 Figure 3 3 Duke s Bookstore Creating a Alter To create a filter in the IDE 1 Mount the Web module as a filesystem 2 Expand the module and WEB INF nodes 3 Right click the classes node and choose New JSP amp Servlet Fil ters gt XXXFilter where XXX is Advanced or Simple You choose Advanced 70 JAVA SERVLET TECHNOLOGY if your filter has a customized request or response otherwise choose Sim ple 4 Type a name for the filter 5 Click Finish Specifying Alter Mappings A Web container uses filter mappings to decide how to apply filters to Web resources A filter mapping matches a filter to a Web component by name or to Web resources by URL pattern The filters are invoked i
482. ternet HTML enables the embedding of images sounds video streams form fields references to other objects with URLs and basic text formatting HTTP Hypertext Transfer Protocol The Internet protocol used to fetch hypertext objects from remote hosts HTTP messages consist of requests from client to server and responses from server to client HTTPS HTTP layered over the SSL protocol ABCDEFGHIJKLMNOPQRSTUVWXYZ impersonation An act whereby one entity assumes the identity and privileges of another entity without restrictions and without any indication visible to the recipients of the impersonator s calls that delegation has taken place Impersonation is a case of simple delegation initialization parameter A parameter that initializes the context associated with a servlet 438 ISO 3166 The international standard for country codes maintained by the International Organization for Standardization ISO ISV Independent Software Vendor ABCDEFGHIJKLMNOPQRSTUVWXYZ J2EE See Java 2 Platform Enterprise Edition J2ME See Java 2 Platform Micro Edition J2SE See Java 2 Platform Standard Edition JAR Java ARchive A platform independent file format that permits many files to be aggregated into one file Java 2 Platform Enterprise Edition J2EE An environment for developing and deploying enterprise applications The J2EE platform consists of a set of services application programming inter faces APIs an
483. th the J2EE XML APIs fully interoperable This does not necessarily mean the data being transported includes XML tags because the transported data can itself be plain text XML data or any kind of binary data such as audio video maps program files CAD documents or the like The next section Extensible Markup Language XML page 3 introduces XML and explains how parties doing business can use XML tags and schemas to exchange data in a meaningful way Extensible Markup Language XML Extensible Markup Language XML is a cross platform extensible and text based standard for representing data When XML data is exchanged between parties the parties are free to create their own tags to describe the data set up schemas to specify which tags can be used in a particular kind of XML docu ment and use XML style sheets to manage the display and handling of the data OVERVIEW For example a Web service can use XML and a schema to produce price lists and companies that receive the price lists and schema can have their own style sheets to handle the data in a way that best suits their needs e One company might put the XML pricing information through a program to translate the XML to HTML so it can post the price lists to its Intranet e A partner company might put the XML pricing information through a tool to create a marketing presentation e Another company might read the XML pricing information into an appli cation for processing
484. that in today s fast moving and demanding world of e commerce and information tech nology enterprise applications have to be designed built and produced for less money with greater speed and with fewer resources than ever before To reduce costs and fast track application design and development Java 2 Platform Enterprise Edition J2EE provides a component based approach to the design development assembly and deployment of enterprise applications The J2EE platform offers a multitiered distributed application model reusable components a unified security model flexible transaction control and Web ser vices support through integrated data interchange on eXtensible Markup Lan guage XML based open standards and protocols Not only can you deliver innovative business solutions to market faster than ever but your platform independent J2EE component based solutions are not tied to the products and application programming interfaces APIs of any one vendor Vendors and customers enjoy the freedom to choose the products and compo nents that best meet their business and technological requirements This tutorial takes an examples based approach to describing the features and functionalities available in J2EE Software Development Kit SDK version 1 4 for developing enterprise applications Whether you are a new or an experienced developer you should find the examples and accompanying text a valuable and accessible knowledge base f
485. that need to maintain state Java Servlet technology pro vides an API for managing sessions and allows several mechanisms for imple menting sessions Accessing a Session Sessions are represented by an HttpSession object You access a session by calling the getSession method of a request object This method returns the cur rent session associated with this request or if the request does not have a ses sion it creates one Since getSession may modify the response header if cookies are the session tracking mechanism it needs to be called before you retrieve a Printwriter or ServletOutputStream Associating Atinbutes with a Session You can associate object valued attributes with a session by name Such attributes are accessible by any Web component that belongs to the same Web context and is handling a request that is part of the same session The Duke s Bookstore application stores a customer s shopping cart as a session attribute This allows the shopping cart to be saved between requests and also allows cooperating servlets to access the cart CatalogServlet adds items to the cart ShowCartServlet displays deletes items from and clears the cart and CashierServlet retrieves the total cost of the books in the cart SESSION MANAGEMENT public class CashierServlet extends HttpServlet public void doGet HttpServletRequest request HttpServletResponse response throws ServletException IOException Get the user s session
486. the application screen lt taglib uri template prefix tt gt lt page errorPage errorpage jsp gt lt include file Screendefinitions jsp gt lt htm1 gt lt head gt lt title gt lt tt insert definition bookstore parameter title gt lt title gt lt head gt lt tt insert definition bookstore parameter banner gt lt tt insert definition bookstore parameter body gt lt body gt lt html gt screendefinitions jsp creates a screen definition based on a request attribute selectedScreen lt tt definition name bookstore screen lt String request getAttribute selectedScreen gt gt lt tt screen id enter gt lt tt parameter name title value Duke s Bookstore direct true gt lt tt parameter name banner value banner jsp direct false gt lt tt parameter name body value bookstore jsp direct false gt lt tt screen gt lt tt screen id catalog gt lt tt parameter name title A TEMPLATE TAG LIBRARY value lt messages getString TitleBookCatalog gt direct true gt lt tt definition gt The template is instantiated by the Dispatcher servlet Dispatcher first gets the requested screen and stores it as an attribute of the request This is necessary because when the request is forwarded to template jsp the request URL doesn t contain the original request for example bookstore3 catalog but instead reflects the path bookst
487. the current item will be of type java util Map Entry which has the following properties e key the key under which the item is stored in the underlying Map e value the value that corresponds to the key Arrays of objects as well as arrays of primitive types for example int are also supported For arrays of primitive types the current item for the iteration is auto matically wrapped with its standard wrapper class for example Integer for int Float for float and so on Implementations of java util Iterator and java util Enumeration are supported but these must be used with caution Iterator and Enumeration objects are not resettable so they should not be used within more than one itera tion tag Finally java lang String objects can be iterated over if the string contains a list of comma separated values for example Monday Tues day Wednesday Thursday Friday Here s the shopping cart iteration from the previous section with the forEach tag lt c forEach var item items sessionScope cart items gt lt tr gt lt td align right bgcolor ffffff gt 163 164 JAVASERVER PAGES STANDARD TAG LIBRARY lt c out value item quantity gt lt td gt lt c forEach gt The forTokens tag is used to iterate over a collection of tokens separated by a delimiter URL Tags The jsp include element provides for the inclusion of static and dynamic resources in the same context as the current page However
488. the following directive lt include file initdestroy jsp gt Because you must statically put an include directive in each file that reuses the resource referenced by the directive this approach has its limitations For a more flexible approach to building pages out of content chunks see A Template Tag Library page 141 The jsp include element is processed when a JSP page is executed The include action allows you to include either a static or dynamic resource in a JSP file The results of including static and dynamic resources are quite different If the resource is static its content is inserted into the calling JSP file If the resource is dynamic the request is sent to the included resource the included page is executed and then the result is included in the response from the calling JSP page The syntax for the jsp include element is lt jsp include page includedPage gt The date application introduced at the beginning of this chapter includes the page that generates the display of the localized date with the following state ment lt jsp include page date jsp gt 99 100 JAVASERVER PAGES TECHNOLOGY Transfering Control to Another Web Component The mechanism for transferring control to another Web component from a JSP page uses the functionality provided by the Java Servlet API as described in Transferring Control to Another Web Component page 74 You access this functionality from a JSP page with t
489. the order input desk the order confirmation desk the shipping desk and the billing department Each of these destinations is an actor that will take the appropriate action remove the header information relevant to it and send the message to the next actor The default actor is the final destina tion so if no actors are specified the message is routed to the final recipient The attribute actor is used to specify an intermediate recipient A related attribute is mustUnderstand which when its value is true means that an actor must understand what it is supposed to do and carry it out successfully A SOAP Header object uses the method addAttribute to add these attributes and the SOAPHeaderElement interface provides methods for setting and getting the val ues of these attributes Figure 10 4 One way Message with Intermediate Destinations When to Use a Messaging Provider A JAXM client may or may not use a messaging provider Generally speaking if you just want to be a consumer of Web services you do not need a messaging MESSAGING PROVIDERS provider The following list shows some of the advantages of not using a mes saging provider e The application can be written using the J2SE platform e The application is not required to be deployed in a servlet container or a J2EE server e No configuration is required The limitations of not using a messaging provider are the following e The client can send only request response me
490. the profiles your messaging provider supports Supposing that you want to use the ebXML profile you need to see if any of the profiles in the array matches ebxml If there is a match that profile is assigned to the variable profile which can then be passed to the method createMessageFactory ProviderMetaData metaData pcCon getMetaData String supportedProfiles metaData getSupportedProfi les String profile null for Cint i 0 i lt supportedProfiles length i if CsupportedProfiles i equalsC ebxm1 profile supportedProfiles i break MessageFactory factory pcCon createMessageFactory profi le You can now use factory to create a SOAPMessage object that conforms to the ebXML profile This example uses the minimal ebXML profile implementation included in the Java WSDP Note that the following line of code uses the class EbXMLMessageImp1 which is defined in the ebXML profile implementation and is not part of the JAXM API EbXMLMessageImpl message CEbXMLMessagelImp1 factory createMessage 311 312 WEB SERVICES MESSAGING WITH JAXM For this profile instead of using Endpoint objects you indicate Party objects for the sender and the receiver This information will appear in the message s header and the messaging provider will use it to determine where to send the message The following lines of code use the methods setSender and setRe ceiver which are defined in the EbXMLMessageImp1 impl
491. the request URL The Web component fills in an HTTP response object which the server converts to an HTTP response and sends to the client This appendix provides some introductory material on the HTTP protocol For further information on this protocol see the Internet RFCs HTTP 1 0 RFC 1945 HTTP 1 1 RFC 2616 which can be downloaded from http ww rfc editor org rfc html 427 428 HTTP OVERVIEW HTIP Requests An HTTP request consists of a request method a request URL header fields and a body HTTP 1 1 defines the following request methods GET retrieves the resource identified by the request URL HEAD returns the headers identified by the request URL POST sends data of unlimited length to the Web server PUT stores a resource under the request URL DELETE removes the resource identified by the request URL OPTIONS returns the HTTP methods the server supports TRACE returns the header fields sent with the TRACE request HTTP 1 0 includes only the GET HEAD and POST methods Although J2EE servers are only required to support HTTP 1 0 in practice many servers includ ing the Java WSDP support HTTP 1 1 HTIP Responses An HTTP response contains a result code header fields and a body The HTTP protocol expects the result code and all header fields to be returned before any body content Some commonly used status codes include 404 indicates that the requested resource is not available 401
492. the standard two tiered client and server model by placing a multithreaded application server between the client application and back end storage OVERVIEW J2EE J2EE Application 1 Application 2 Client Client Tier Machine am Web Tier J2EE Server a Machine Enterprise Enterprise Business Beans Beans Tier EIS Database Database Database Tier Server Machine Figure 1 1 Multitiered Applications J 2EE Components J2EE applications are made up of components A J2EE component is a self con tained functional software unit that is assembled into a J2EE application with its related classes and files and that communicates with other components The J2EE specification defines the following J2EE components e Application clients and applets are components that run on the client e Java Servlet and JavaServer Pages JSP technology components are Web components that run on the server e Enterprise JavaBeans EJB components enterprise beans are busi ness components that run on the server J2EE components are written in the Java programming language and are com piled in the same way as any program in the language The difference between J2EE components and standard Java classes is that J2EE components are assembled into a J2EE application verified to be well formed and in compliance with the J2EE specification and deployed to production where they are run and managed by the J2EE server J2EE
493. the value of the scripting variable to the next element and returns EVAL_BODY_AGAIN to indicate that the body should be evaluated again This causes the reexecution of doAf terBody When there are no remaining elements doAfterBody terminates the process by returning SKIP_BODY public int doStartTag throws JspException JspException otherDoStartTagOperations if theBodyShouldBeEvaluated return EVAL_BODY_INCLUDE else return SKIP_BODY public void otherDoStartTagOperations if group size Q gt 0 iterator group iterator public boolean theBodyShouldBeEvaluated if Citerator hasNextQ pageContext setAttribute name iterator nextQ return true else return false public int doAfterBody throws JspException if theBodyShouldBeEvaluatedAgain return EVAL_BODY_AGAIN else return SKIP_BODY A TEMPLATE TAG LIBRARY 141 public boolean theBodyShouldBeEvaluatedAgain if Citerator hasNextQd pageContext setAttribute name iterator nextQ return true else return false Tag Extra Info Class Information about the scripting variable is provided in the IteratorTEI tag extra info class The name and class of the scripting variable are passed in as the name and type tag attributes and used to fill in the VariableInfo constructor public VariableInfo getVariableInfo TagData data VariableInfo infol new VariableInfo data getAttributeStringC name data
494. this case the name of the entity is the hash mark followed by the digits that iden tify the character Note XML expects values to be specified in decimal However the Unicode charts at http www unicode org charts specify values in hexadecimal So you ll need to do a conversion to get the right value to insert into your XML data set Using an Entity Reference in an XML Document Suppose you wanted to insert a line like this in your XML document Market Size lt predicted The problem with putting that line into an XML file directly is that when the parser sees the left angle bracket lt it starts looking for a tag name which throws off the parse To get around that problem you put amp 1t in the file instead of aa ae Note The results of the modifications below are contained in s1ideSamp1eQ3 xm1 SUBSTITUTING AND INSERTING TEXT Add the text highlighted below to your slideSample xm1 file and save a copy of it for future use as slideSamp1eQ3 xm1 lt OVERVIEW gt lt slide type all1 gt lt title gt Overview lt title gt wisladex lt slide type exec gt lt title gt Financial Forecast lt title gt lt item gt Market Size amp 1t predicted lt item gt lt item gt Anticipated Penetration lt item gt lt item gt Expected Revenues lt item gt lt item gt Profit Margin lt item gt lt slide gt lt slideshow gt When you use an XML parser to echo this data you will see the desired outpu
495. thods that allow you to do the following e Retrieve an output stream to use to send data to the client To send charac ter data use the PrintWriter returned by the response s getWriter method To send binary data in a MIME body response use the Serv JTetOutputStream returned by getOutputStream To mix binary and text data for example to create a multipart response use a ServletOutput Stream and manage the character sections manually e Indicate the content type for example text htm1 being returned by the response A registry of content type names is kept by the Internet Assigned Numbers Authority IANA at ftp ftp isi edu in notes iana assignments media types e Indicate whether to buffer output By default any content written to the output stream is immediately sent to the client Buffering allows content to be written before anything is actually sent back to the client thus providing the servlet with more time to set appropriate status codes and headers or forward to another Web resource e Set localization information HTTP response objects HttpServletResponse have fields representing HTTP headers such as e Status codes which are used to indicate the reason a request is not satis fied e Cookies which are used to store application specific information at the cli ent Sometimes cookies are used to maintain an identifier for tracking a user s session see Session Tracking page 78 In Duke s Bookstore
496. tifiers or external links The next step is to go through the concepts find the WSDL documents they cor respond to and display the organizations that use each document Display information about the concepts found Collection specConcepts br getCollection Iterator iter specConcepts iterator if Cliter hasNextQ System out printInC No WSDL specification concepts found else while Citer hasNext Concept concept Concept iter nextQ String name getName concept Collection links concept getExternalLinks System out printInC nSpecification Concept n tName name n tKey concept getKey getIdQ n tDescription 360 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR getDescription concept if Clinks sizeQ gt 0 ExternalLink link CExternalLink links iterator Q nextQ System out printInC tURL of WSDL document link getExternalURIQ Find organizations that use this concept Collection specConceptsl new ArrayListQ specConcepts1 add concept br bqm findOrganizations null null null specConcepts1 null null Display information about organizations If you find an organization that offers a service you wish to use you can invoke the service using the JAX RPC API Finding Services and Servic eBindings After a client has located an organization it can find that organization s services and the service bindings assoc
497. ting with JAXR 361 finding by classification 358 377 by name 357 376 using WSDL documents 377 keys 361 365 primary contacts 361 publishing 376 removing 377 with JAXR 365 saving with JAXR 364 P packages javax xml messaging 290 javax xml registry 349 javax xml registry infomod e1 349 javax xml soap 290 javax xml1 transform 248 packaging 254 parameter entity 225 470 INDEX parsed character data 212 entity 222 PCDATA 212 versus CDATA 212 pluggability layer 242 point to point connection 303 postal addresses retrieving 371 378 specifying 369 378 prerequisites viii printing the tutorial xi PrintWriter 62 processing data 185 instructions 182 204 profiles 259 299 ebXML 299 311 implementations 312 Javadoc documentation 299 SOAP RP 299 provider JAXR 349 ProviderConnection object 258 297 310 ProviderConnection send meth od 297 298 315 proxies 269 277 HTTP setting 354 R RDF 196 schema 196 registering businesses 263 registries definition 348 ebXML 348 349 getting access to public UDDI registries 351 private 349 querying 356 searching 264 submitting data 361 UDDI 348 UDDI Server Registry 349 using public and private 373 registry objects 349 retrieving 381 Registry Server See J2EE SDK Registry Server RegistryObject interface 349 RegistryService interface 349 356 RELAX NG 193 release 131 remote method invocation 255 remote procedure call See RPC remote procedure c
498. tion and send a reply informing the customer that the order will be filled If the quantity ordered is not available the implementation might place its own order to replenish its supply and notify the customer that the coffee is backor dered package coffees public class CoffeeOrderImp implements CoffeeOrderlIF public Coffee getPriceListQ throws RemoteException public String orderCoffee String coffeeName int quantity throws RemoteException After writing the service s interface and implementation class the developer s next step is to generate the helper classes The final steps in creating a Web ser vice are packaging and deployment A Web service definition is packaged in a Web application archive WAR For example the CoffeeOrder service could be packaged in the file jaxrpc coffees war which makes it easy to distribute and deploy Coding a Client Writing the client application for a Web service entails simply writing code that invokes the desired method Of course much more is required to build the remote method call and transmit it to the Web service but that is all done behind the scenes and is invisible to the client The following class definition is an example of a Web services client It creates an instance of CoffeeOrderIF and uses it to call the method getPriceList Then it accesses the price and name fields of each Coffee object in the array returned by the method getPriceList in order to
499. tion screens you will get an order con firmation that looks like the one shown in Figure 12 3 x Confirmation Netscape tto localhost 8080 cbserver checkoutAck Gall Continue Shopping Copyright 2002 Sun Microsystems Inc Figure 12 3 Order Confirmation A Java Encoding Schemes This appendix describes the character encoding schemes that are supported by the Java platform US ASCII US ASCII is a 7 bit encoding scheme that covers the English language alphabet It is not large enough to cover the characters used in other lan guages however so it is not very useful for internationalization ISO 8859 1 This is the character set for Western European languages It s an 8 bit encod ing scheme in which every encoded character takes exactly 8 bits With the remaining character sets on the other hand some codes are reserved to sig nal the start of a multi byte character UTEF 8 UTF 8 is an 8 bit encoding scheme Characters from the English language alphabet are all encoded using an 8 bit bytes Characters for other languages are encoded using 2 3 or even 4 bytes UTF 8 therefore produces compact documents for the English language but for other languages documents tend to be half again as large as they would be if they used UTF 16 If the majority of a document s text is in a Western European language then UTF 8 is generally a good choice because it allows for internationalization while still minimizing the
500. tlet For example showcart jsp removes a book from a shopping cart using a scriptlet The ID of the book to be removed is passed as a request parameter The value of the request parameter is first set as a page attribute to be used later by the JSTL sql query tag and then declared as scripting variable and passed to the cart remove method lt c set var bookId value param Remove gt lt jsp useBean id bookId type java lang String gt lt Cart remove bookId gt lt sql query var books dataSource applicationScope bookDS gt select from PUBLIC books where id lt sql param value bookId gt lt sql query gt FLOW CONTROL TAGS The catch tag provides a complement to the JSP error page mechanism It allows page authors to recover gracefully from error conditions that they can control Actions that are of central importance to a page should not be encapsu lated in a catch so their exceptions will propagate to an error page Actions with secondary importance to the page should be wrapped in a catch so they never cause the error page mechanism to be invoked The exception thrown is stored in the scoped variable identified by var which always has page scope If no exception occurred the scoped variable identified by var is removed if it existed If var is missing the exception is simply caught and not saved How Contol Tags To execute flow control logic a page author must generally resort to using sc
501. to reference a DESIGNING AN XML DATA STRUCTURE local copy of the XHTML DTD or some mirrored version with a potentially beneficial impact on performance Designing an XML Data Structure This section covers some heuristics you can use when making XML design deci sions Saving Yourself Some Work Whenever possible use an existing schema definition It s usually a lot easier to ignore the things you don t need than to design your own from scratch In addi tion using a standard DTD makes data interchange possible and may make it possible to use data aware tools developed by others So if an industry standard exists consider referencing that DTD with an external parameter entity One place to look for industry standard DTDs is at the reposi tory created by the Organization for the Advancement of Structured Information Standards OASIS at http www XML org Another place to check is Com merceOne s XML Exchange at http www xm1x com which is described as a repository for creating and sharing document type definitions Note Many more good thoughts on the design of XML structures are at the OASIS page http www oasis open org cover elementsAndAttrs htm1 Attributes and Elements One of the issues you will encounter frequently when designing an XML struc ture is whether to model a given data item as a subelement or as an attribute of an existing element For example you could model the title of a slide either a
502. to specify a servlet path for a JSP page unless you wish to refer to the page by a name other than its file CONFIGURING WEB MODULES 31 name In the Hello2 example the greeting page has a servlet path but response jsp is called by name To view the servlet path for the Hello2 application 1 In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web hel1o2 Expand the nodes he1102 Select the greeting JSP page Select the Deployment Entries property and open the property editor nA BW N Notice that the JSP page greeting jsp has the servlet name greeting and is mapped to the URL greeting Initialization Parameters The Web components in a Web module share an object that represents their application context see Accessing the Web Context page 75 You can pass ini tialization parameters to the context or Web component To add a context parameter in the IDE Mount the Web module as a filesystem and expand it Expand the WEB INF node Select the web xm1 file Select the Deployment tab in the property editor Select the Context Parameters property and open the property editor Click Add Type the parameter name and value Click OK twice CONN NN FW NY For an example context parameter page mapping see The Example JSP Pages page 150 To add a Web component initialization parameter in the IDE 1 Mount the Web module as a filesystem and expand it 2 Select the Web compo
503. to write your own implementation of a message factory and plug it in via system properties but the default message factory is the one that will generally be used The other way to get a MessageFactory object is to retrieve it from a naming service where it has been registered This way is available only to applications that use a messaging provider and it will be covered later in Creating a Message page 311 303 304 WEB SERVICES MESSAGING WITH JAXM Parts of a Message A SOAPMessage object is required to have certain elements and the SAAJ API simplifies things for you by returning a new SOAPMessage object that already contains these elements So message which was created in the preceding line of code automatically has the following I A SOAPPart object that contains A A SOAPEnvelope object that contains 1 An empty SOAPHeader object 2 An empty SOAPBody object The SOAPHeader object though optional is included for convenience because most messages will use it The SOAPBody object can hold the content of the mes sage and can also contain fault messages that contain status information or details about a problem with the message The section SOAP Faults page 319 walks you through how to use SOAPFau1t objects Accessing Hements of a Message The next step in creating a message is to access its parts so that content can be added The SOAPMessage object message created in the previous code fragment is where to start It con
504. toCommit true releaseConnectionQ catch Exception ex try con rollbackQ releaseConnection throw new OrderException Transaction failed ex getMessage catch SQLException sqx releaseConnection throw new OrderExceptionC Rollback failed sqx getMessage Inttalizing a Servlet After the Web container loads and instantiates the servlet class and before it delivers requests from clients the Web container initializes the servlet You can customize this process to allow the servlet to read persistent configuration data initialize resources and perform any other one time activities by overriding the WRITING SERVICE METHODS init method of the Servlet interface A servlet that cannot complete its initial ization process should throw Unavai lableException All the servlets that access the bookstore database BookStoreServlet Cata logServlet BookDetailsServlet and ShowCartServlet initialize a variable in their init method that points to the database helper object created by the Web context listener public class CatalogServlet extends HttpServlet private BookDB bookDB public void initQ throws ServletException bookDB BookDB getServletContextQ getAttributeC bookDB if CbookDB null throw new Unavai lableException Couldn t get database Whiting Service Methods The service provided by a servlet is implemented in the service method of a GenericServlet the doMethod methods whe
505. torial examples jaxr direc tory are as follows JAXRQuery java shows how to search a registry for organizations JAXRQueryByNAICSClassi fication java shows how to search a registry using a common classification scheme JAXRQueryByWSDLClassi fication java shows how to search a registry for Web services that describe themselves by means of a WSDL document JAXRPublish java shows how to publish an organization to a registry JAXRDelete java shows how to remove an organization from a registry JAXRSaveClassificationScheme java shows how to publish a classifi cation scheme specifically a postal address scheme to a registry JAXRPublishPostal java shows how to publish an organization with a postal address for its primary contact JAXRQueryPostal java shows how to retrieve postal address data from an organization JAXRDeleteScheme java shows how to delete a classification scheme from a registry JAXRGetMyObjects java lists all the objects that you own in a registry The lt INSTALL gt j2eetutorial examples jaxr directory also contains A JAXRExamples properties file in the src subdirectory that supplies string values used by the sample programs A file called postalconcepts xm1 that you use with the postal address examples A file called postal properties that specifies the location of the user taxonomy file for the postal address examples The instructions that follow assume that you have started Sun ONE Studio You do not n
506. ts then one aspect of the validation criteria for the data has been defined it only remains to write the code Although a DTD specification cannot go the same level of detail a DTD like a schema provides a grammar that tells which data structures can occur in what sequences That specification tells you how to write the high level code that processes the data elements But when the data structure and possibly format is fully specified the code you need to process it can just as easily be generated automatically That process is known as binding creating classes that recognize and process different data elements by processing the specification that defines those elements As time goes on you should find that you are using the data specification to generate sig nificant chunks of code so you can focus on the programming that is unique to your application Archiving The Holy Grail of programming is the construction of reusable modular compo nents Ideally you d like to take them off the shelf customize them and plug them together to construct an application with a bare minimum of additional coding and additional compilation The basic mechanism for saving information is called archiving You archive a component by writing it to an output stream in a form that you can reuse later You can then read it in and instantiate it using its saved parameters For exam XML AND RELATED SPECS DIGESTING THE ALPHABET SOUP 187 ple if
507. ttachment getContent String id attachment getContentIdQ System out printC Attachment id content System out printIn contains Summary In this section you have been introduced to the basic JAXM API You have seen how to create and send SOAP messages as a standalone client and as a client using a messaging provider You have walked through adding content to a SOAP SOAP FAULTS header and a SOAP body and also walked through creating attachments and giv ing them content In addition you have seen how to retrieve the content from the SOAP part and from attachments In other words you have walked through using the basic JAXM API SOAP Faults This section expands on the basic JAXM API by showing you how to use the API for creating and accessing a SOAP Fault element in an XML message Overview If you send a message that was not successful for some reason you may get back a response containing a SOAP Fault element that gives you status information error information or both There can be only one SOAP Fault element in a mes sage and it must be an entry in the SOAP Body The SOAP 1 1 specification defines only one Body entry which is the SOAP Fault element Of course the SOAP Body may contain other Body entries but the SOAP Fault element is the only one that has been defined A SOAPFault object the representation of a SOAP Fault element in the JAXM API is similar to an Exception object in that it conveys
508. tual data JSP pages are more appropriate for generating text based markup such as HTML SVG WML and XML Web components are supported by the services of a runtime platform called a Web container The Web container provides services such as request dispatching 25 26 INTRODUCTION TO WEB APPLICATIONS security concurrency and life cycle management It also gives Web components access to APIs such as naming transactions and e mail Certain aspects of Web application behavior can be configured when the applica tion is deployed to the Web container The configuration information is main tained in a text file in XML format called a Web application deployment descriptor A deployment descriptor must conform to the schema described in the Java Servlet specification This chapter describes the organization configuration and installation and deployment procedures for Web applications Chapters 9 and 10 cover how to develop Web components for service oriented Web applications Chapters 3 and 4 cover how to develop the Web components for presentation oriented Web applications Many features of JSP technology are determined by Java Servlet technology so you should familiarize yourself with that material even if you do not intend to write servlets Most Web applications use the HTTP protocol and support for HTTP is a major aspect of Web components For a brief summary of HTTP protocol features see HTTP Overview page 427 Web Applicati
509. tuting and Inserting Text In this section you ll learn about e Handling Special Characters lt amp and so on e Handling Text with XML style syntax Handling Special Characters In XML an entity is an XML structure or plain text that has a name Referenc ing the entity by name causes it to be inserted into the document in place of the entity reference To create an entity reference the entity name is surrounded by an ampersand and a semicolon like this amp entityName Later when you learn how to write a DTD you ll see that you can define your own entities so that amp yourEntityName expands to all the text you defined for that entity For now though we ll focus on the predefined entities and character references that don t require any special definitions Predefined Entities An entity reference like amp amp contains a name in this case amp between the start and end delimiters The text it refers to amp is substituted for the name like a macro in a programming language Table 7 1 shows the predefined entities for special characters Table 7 1 Predefined Entities 207 208 UNDERSTANDING XML Character References A character reference like amp 147 contains a hash mark followed by a num ber The number is the Unicode value for a single character such as 65 for the letter A 147 for the left curly quote or 148 for the right curly quote In
510. tween clients and enterprise beans After an enterprise bean is created a client invokes methods on it as if it were in the same virtual machine The fact that the J2EE architecture provides configurable services means that application components within the same J2EE application can behave differently based on where they are deployed For example an enterprise bean can have security settings that allow it a certain level of access to database data in one pro duction environment and another level of database access in another production environment The container also manages nonconfigurable services such as enterprise bean and servlet life cycles database connection resource pooling data persistence and access to the J2EE platform APIs described in the section J2EE APIs page 17 Although data persistence is a nonconfigurable service the J2EE architecture lets you override container managed persistence by including the appropriate code in your enterprise bean implementation when you want more control than the default container managed persistence provides For example you might use bean managed persistence to implement your own finder search methods or to create a customized database cache Container Types The deployment process installs J2EE application components in the J2EE con tainers illustrated in Figure 1 5 PACKAGING 13 J2EE Server Il Servlet JSP Page Web Container A i l Database Application Clien
511. ucture Thus unlike a SAX parser a DOM parser allows random access to particular pieces of data in an XML document Another differ ence is that with a SAX parser you can only read an XML document but with a DOM parser you can build an object representation of the document and manip ulate it in memory adding a new element or deleting an existing one In the previous example we used a SAX parser to look for just one piece of data in a document Using a DOM parser would have required having the whole doc ument object model in memory which is generally less efficient for searches involving just a few items especially if the document is large In the next exam ple we add a new coffee to the price list using a DOM parser We cannot use a SAX parser for modifying the price list because it only reads data Let s suppose that you want to add Kona coffee to the price list You would read the XML price list file into a DOM and then insert the new coffee element with its name and price The following code fragment creates a DocumentBui 1derFac tory object which is then used to create the DocumentBui Ider object builder The code then calls the parse method on builder passing it the file priceList xml DocumentBuilderFactory factory DocumentBui lderFactory newInstanceQ DocumentBuilder builder factory newDocumentBui lder Document document builder parseC priceList xml At this point document is a DOM representation of the pri
512. ue Collection classifications new ArrayList classifications add classification org addClassifications classifications Next it adds the JAX RPC service called JAXRPCCoffee Service and its ser vice binding The access URI for the service binding contains the endpoint URL that remote clients will use to contact our service http localhost 80 SupplierService SupplierService 390 THE COFFEE BREAK APPLICATION JAXR validates each URI so an exception is thrown if the service was not deployed before you ran this program Collection services new ArrayListQ Service service blcm createService bundle getStringC service name InternationalString is blcm createInternationalString Cbundle getStringC service description service setDescription is Create service bindings Collection serviceBindings new ArrayList ServiceBinding binding blcm createServiceBinding is blcm createInternationalString Cbundle getStringC service binding binding setDescription is try binding setAccessURI endpoint catch CJAXRException je throw new JAXRExceptionC Error Publishing this service in the registry has failed because the service has not been deployed on the application server serviceBindings add binding Add service bindings to service service addServiceBindings serviceBindings Add service to services then add services to organization services add service
513. uire any structure So it is natural to define them as attributes of the slide show element Add the text highlighted below to set up some attributes lt slideshow title Sample Slide Show date Date of publication author Yours Truly gt lt slideshow gt When you create a name for a tag or an attribute you can use hyphens underscores _ colons and periods in addition to characters and numbers Unlike HTML values for XML attributes are always in quotation marks and multiple attributes are never separated by commas Note Colons should be used with care or avoided altogether because they are used when defining the namespace for an XML document 202 UNDERSTANDING XML Adding Nested Hements XML allows for hierarchically structured data which means that an element can contain other elements Add the text highlighted below to define a slide element and a title element contained within it lt slideshow gt lt TITLE SLIDE gt lt slide type all1 gt lt title gt Wake up to WonderWidgets lt title gt lt slide gt lt slideshow gt Here you have also added a type attribute to the slide The idea of this attribute is that slides could be earmarked for a mostly technical or mostly executive audi ence with type tech or type exec or identified as suitable for both with type al1 More importantly though this example illustrates the difference between t
514. un ONE Studio these APIs are available in the directory lt S1STUDIO_HOME gt jwsdp common 1 ib The remainder of this introduction first gives an overview of the Java APIs for XML explaining what they do and how they make writing Web applications eas ier It then describes each of the APIs individually and then presents a scenario that illustrates how they can work together The tutorials that follow give more detailed explanations and walk you through how to use the Java APIs for XML to build applications for Web services They also provide sample applications that you can run Overview of the J ava APis for XML The Java APIs for XML let you write your Web applications entirely in the Java programming language They fall into two broad categories those that deal directly with processing XML documents and those that deal with procedures Document oriented e Java API for XML Processing JAXP processes XML documents using various parsers e Procedure oriented e Java API for XML based RPC JAX RPC sends SOAP method calls to remote parties over the Internet and receives the results e Java API for XML Messaging JAXM sends SOAP messages over the Internet in a standard way e Java API for XML Registries JAXR provides a standard way to access business registries and share information Perhaps the most important feature of the Java APIs for XML is that they all sup port industry standards thus ensuring interope
515. used to initialize the javax activa tion DataHandler object dh The Message object m creates the Attachment Part object attachPart which is initialized with the data handler containing the URL for the image Finally the message adds attachPart to itself URL url new URLC http foo bar img jpg DataHandler dh new DataHandler ur1 AttachmentPart attachPart m createAttachmentPart dh m addAttachmentPart attachPart 261 262 INTRODUCTION TO WEB SERVICES A SOAPMessage object can also give content to an AttachmentPart object by passing an Object and its content type to the method createAttachmentPart AttachmentPart attachPart m createAttachmentPart content string text plain m addAttachmentPart attachPart A third alternative is to create an empty AttachmentPart object and then to pass the AttachmentPart setContent method an Object and its content type In this code fragment the Object is a ByteArrayInputStream initialized with a jpeg image AttachmentPart ap m createAttachmentPart byte jpegData ap setContent new ByteArrayInputStream jpegData image jpeg m addAttachmentPart ap Sending a Message Once you have populated a SOAPMessage object you are ready to send it A stan dalone client uses the SOAPConnection method call to send a message This method sends the message and then blocks until it gets back a response The arguments to the method call are the message being se
516. vaBeans Components in J SP Pages JavaBeans components are Java classes that can be easily reused and composed together into applications Any Java class that follows certain design conventions can be a JavaBeans component JavaServer Pages technology directly supports using JavaBeans components with JSP language elements You can easily create and initialize beans and get and set the values of their properties This chapter provides basic information about JavaBeans components and the JSP language elements for accessing Java Beans components in your JSP pages For further information about the Java Beans component model see http java sun com products javabeans J avaBeans Component Design Conventions JavaBeans component design conventions govern the properties of the class and govern the public methods that give access to the properties A JavaBeans component property can be e Read write read only or write only e Simple which means it contains a single value or indexed which means it represents an array of values 104 JAVASERVER PAGES TECHNOLOGY There is no requirement that a property be implemented by an instance variable the property must simply be accessible using public methods that conform to certain conventions e For each readable property the bean must have a method of the form PropertyClass getProperty e For each writable property the bean must have a method of the form setProperty PropertyClass p
517. vax servlet package You define a filter by implementing the Filter interface The most important method in this interface is the doFil ter method which is passed request response and filter chain objects This method can perform the following actions e Examine the request headers e Customize the request object if it wishes to modify request headers or data e Customize the response object if it wishes to modify response headers or data e Invoke the next entity in the filter chain If the current filter is the last filter in the chain that ends with the target Web component or static resource the next entity is the resource at the end of the chain otherwise it is the next 65 66 JAVA SERVLET TECHNOLOGY filter that was configured in the WAR It invokes the next entity by calling the doFilter method on the chain object passing in the request and response it was called with or the wrapped versions it may have created Alternatively it can choose to block the request by not making the call to invoke the next entity In the latter case the filter is responsible for filling out the response e Examine response headers after it has invoked the next filter in the chain e Throw an exception to indicate an error in processing In addition to doFilter you must implement the init and destroy methods The init method is called by the container when the filter is instantiated If you wish to pass initialization parameters to the f
518. velope env sp getEnvelope SOAPBody sb env getBody Name newBodyName env createName confirmation Confirm http sonata coffeebreak com SOAPBodyElement confirm sb addBodyE1ement newBodyName create the orderID element for confirmation COFFEE BREAK SERVER 401 Name newOrderIDName env createNameC orderId SOAPElement newOrderNo confirm addChi 1dElement newOrderIDName newOrderNo addTextNode sentID create ship date element Name shipDateName env createName ship date SOAPElement shipDate confirm addChi 1dElement shi pDateName create the shipping date Date today new DateQ long msPerDay 1000 60 60 24 long msTarget today getTimeQ long msSum msTarget msPerDay 2 Date result new Date result setTime msSum String sd result toStringQ shipDate addTextNode sd confirmation saveChanges catch Exception ex ex printStackTraceQ return confirmation Coffee Break Server The Coffee Break Server uses servlets JSP pages and JavaBeans components to dynamically construct HTML pages for consumption by a Web browser client The JSP pages use the template tag library discussed in A Template Tag Library page 141 to achieve a common look and feel among the HTML pages and many of the JSTL custom tags discussed in Chapter 6 to minimize the use of scripting The Coffee Break Server implementation is organized along the Model V
519. version is s ideshowla dtd htm1 Start by creating a file named slideshow dtd Enter an XML declaration and a comment to identify the file as shown below lt xml version 1 encoding utf 8 gt lt DTD for a simple slide show gt Next add the text highlighted below to specify that a slideshow element con tains slide elements and nothing else lt DTD for a simple slide show gt lt ELEMENT slideshow slide gt As you can see the DTD tag starts with lt followed by the tag name ELEMENT After the tag name comes the name of the element that is being defined slide show and in parentheses one or more items that indicate the valid contents for that element In this case the notation says that a slideshow consists of one or more slide elements 211 212 UNDERSTANDING XML Without the plus sign the definition would be saying that a s1ideshow consists of a single slide element The qualifiers you can add to an element definition are listed in Table 7 2 Table 7 2 DTD Element Qualifiers Question Mark Optional zero or one Asterisk Zero or more Plus Sign One or more You can include multiple elements inside the parentheses in a comma separated list and use a qualifier on each element to indicate how many instances of that element may occur The comma separated list tells which elements are valid and the order they can occur in You can also nest parentheses to group
520. very component type Because you do not have to develop these ser vices yourself you are free to concentrate on solving the business problem at hand Container Services Containers are the interface between a component and the low level platform specific functionality that supports the component Before a Web enterprise bean or application client component can be executed it must be assembled into a J2EE application and deployed into its container 11 12 OVERVIEW The assembly process involves specifying container settings for each component in the J2EE application and for the J2EE application itself Container settings customize the underlying support provided by the J2EE server which includes services such as security transaction management Java Naming and Directory Interface JNDI lookups and remote connectivity Here are some of the high lights e The J2EE security model lets you configure a Web component or enter prise bean so that system resources are accessed only by authorized users e The J2EE transaction model lets you specify relationships among methods that make up a single transaction so that all methods in one transaction are treated as a single unit e JNDI lookup services provide a unified interface to multiple naming and directory services in the enterprise so that application components can access naming and directory services e The J2EE remote connectivity model manages low level communications be
521. vice helloWsd1Ur1 new QName nameSpaceUri serviceName A Service object is a factory for proxies To create the Service object helloService the program calls the createService method on another type of factory a ServiceFactory object The createService method has two parameters the URL of the WSDL file and a QName object In this example the URL of the WSDL file points to the WSDL that has been deployed with MyHe11oService http localhost 80 MyHel 1loService MyHel 1loService WSDL A QName object is a tuple that represents an XML qualified name The tuple is composed of a namespace URI and the local part of the qualified name In the QName parameter of the createService invocation the local part is the service name MyHel loService 2 From helloService creates a proxy myProxy with a type of the service definition interface MyHel oServiceRPC MyHelloServiceRPC myProxy MyHelloServiceRPC helloService getPort new QName nameSpaceUri portName MyHelloServiceRPC class The helloService object is a factory for dynamic proxies To create myProxy the program calls the getPort method of helloService This method has two parameters a QName object that specifies the port name DYNAMIC PROXY CLIENT EXAMPLE 281 and a java lang Class object for the service definition interface The port name MyHelloServiceRPCPort is specified by the WSDL file When the IDE creates the WSDL it constructs the port name by appending RPC
522. vice package The source code for the placeOrder method follows public ConfirmationBean placeOrder OrderBean order Date tomorrow com sun cb DateHelper addDays new Date 1 ConfirmationBean confirmation new ConfirmationBean order getId Q tomorrow return confirmation Publishing the Service in the Registry Because we want customers to find our service we will to publish it in a registry The programs that publish and remove our service are called OrgPublisher and OrgRemover Although related to the service these programs are not part of the service s Web application that is the servlet that implements the service They are stand alone programs that are run separately These programs reside in the lt INSTALL gt j2eetutorial examples cb jaxrpc registry directory The OrgPublisher program begins by loading String values from the Cof feeRegistry properties file Next the program instantiates a utility class named JAXRPublisher OrgPublisher connects to the registry by invoking the makeConnection method of JAXRPublisher To publish the service OrgPub lisher invokes the executePublish method which accepts as input username password and endpoint The username and password values are required by the Registry Server The endpoint value is the URL that remote clients will use to contact our JAX RPC service The executePublish method of JAXRPub lisher returns a key that uniquely identifies the service in the registry Org
523. vigate to lt S1AS7_HOME gt pointbase server 3 Execute StartServer POPULATING THE EXAMPLE DATABASE Populating the Example Database The Sun ONE Application Server 7 is distributed with a sample database that contains the table required for the Duke s Bookstore examples The table is accessible only to the user name BOOKSTORE If you need to repopulate the data base 1 Start the PointBase console tool a Open a terminal window b Navigate to lt S1AS7_HOME gt pointbase client_tools c Execute PB_console In the PointBase console window connect to the database jdbc point base server localhost sun appserv samples with user name PBPUBLIC and password PBPUBLIC In the IDE mount the filesystem lt INSTALL gt j2eetutorial examples web bookstore 4 Expand the bookstore node Oo ON DD In the PointBase console window execute the SQL statements in cre ateUser sql a Copy the SQL statements in createUser sql b Paste the SQL statements into the text area labeled Enter SQL Com mands by choosing Edit Paste in the PointBase console window c Choose SQL Execute All Choose DBA gt Disconnect from Database Choose DBA gt Connect to Database Type BOOKSTORE for the user name and BOOKSTORE for the password In the PointBase console window execute the SQL statements in book store sql At the end of the processing you should see the following out put java ID java
524. volved in accom plishing the delivery MESSAGING PROVIDERS Profiles JAXM offers the ability to plug in additional protocols that are built on top of SOAP A JAXM provider implementation is not required to implement features beyond what the SOAP 1 1 and SOAP with Attachments specifications require but it is free to incorporate other standard protocols called profiles that are implemented on top of SOAP For example the ebXML Message Service Spec ification available at http www oasis open org committees ebxml msg defines levels of service that are not included in the two SOAP specifica tions A messaging provider that is implemented to include ebXML capabilities on top of SOAP capabilities is said to support an ebXML profile A messaging provider may support multiple profiles but an application can use only one at a time and must have a prior agreement with each of the parties to whom it sends messages about what profile is being used Profiles affect a message s headers For example depending on the profile a new SOAPMessage object will come with certain headers already set Also a profile implementation may provide API that makes it easier to create a header and set its content The JAXM reference implementation includes APIs for both the ebXML and SOAP RP profiles The Javadoc documentation for these profiles is at lt S1STUDIO_HOME gt jwsdp docs jaxm profiles index htm You will find links to the Javadoc documentation
525. w of J AXR This section covers the following topics e What is a registry e What is JAXR e JAXR architecture 347 348 PUBLISHING AND DISCOVERING WEB SERVICES WITH JAXR What Is a Registry An XML registry is an infrastructure that enables the building deployment and discovery of Web services It is a neutral third party that facilitates dynamic and loosely coupled business to business B2B interactions A registry is availa le to organizations as a shared resource often in the form of a Web based service Currently there are a variety of specifications for XML registries These include e The ebXML Registry and Repository standard which is sponsored by the Organization for the Advancement of Structured Information Standards OASIS and the United Nations Centre for the Facilitation of Procedures and Practices in Administration Commerce and Transport U N CEFACT e The Universal Description Discovery and Integration UDDI project which is being developed by a vendor consortium A registry provider is an implementation of a business registry that conforms t gt a specification for XML registries What Is J AXR JAXR enables Java software programmers to use a single easy to use abstrac tion API to access a variety of XML registries A unified JAXR information model describes content and metadata within XML registries JAXR gives developers the ability to write registry client programs that are por table across
526. ware It focuses on teaching the concepts of J2EE technologies through an extensive set of examples and provides basic instructions in how to use the software so that you can develop configure build deploy and run the examples To learn how to use the software see the resources listed in Further Information page x vii viii Prerequisites To understand this tutorial you will need a good knowledge of the Java program ming language SQL and relational database concepts The topics listed in Table P 1 The Java Tutorial are particularly relevant Table P 1 Relevant Topics in The Java Tutorial JDBC http java sun com docs books tutorial jdbc Threads http java sun com docs books tutorial essential threads JavaBeans http java sun com docs books tutorial javabeans How to Read This Tutonal This tutorial is organized into the following sections e Introduction These chapters introduce the J2EE platform and the fundamentals of Web applications They are prerequisites for the rest of the tutorial e Overview e Web Applications e Web Technology These chapters cover the technologies used in developing presentation oriented Web applications e Java Servlets e JavaServer Pages e JSP custom tags e The JSP Standard Tag Library JSTL e Java Web Services Technology These chapters cover the technologies used in developing service oriented Web applications ABOUT THE EXAMPLES e Defining RPC or
527. with message driven beans and JMS JTA and JNDI You can learn more about using the J2EE platform to build integrated business systems by reading J2EE Technology in Practice http java sun com j2ee inpractice aboutthebook htm 24 OVERVIEW 2 Intoduction to Web Applications Stephanie Bodoff A Web application is a dynamic extension of a Web server There are two types of Web applications e Presentation oriented A presentation oriented Web application generates dynamic Web pages containing various types of markup language HTML XML and so on in response to requests e Service oriented A service oriented Web application implements the end point of a fine grained Web service Service oriented Web applications are often invoked by presentation oriented applications In the Java 2 Platform Web components provide the dynamic extension capabili ties for a Web server Web components are either Java Servlets or JSP pages Servlets are Java programming language classes that dynamically process requests and construct responses JSP pages are text based documents that exe cute as servlets but allow a more natural approach to creating static content Although servlets and JSP pages can be used interchangeably each has its own strengths Servlets are best suited to service oriented Web applications and man aging the control functions of a presentation oriented application such as dis patching requests and handling nontex
528. ws enough to substitute something like Image not found On the other hand the src attribute which names the image to display is required The type attribute is intended for the specification of a MIME data type as defined at ftp ftp isi edu in notes iana assignments media types It has a default value image gif Note It is understood here that the character data CDATA used for the type attribute will be one of the MIME data types The two most common formats are image gif and image jpeg Given that fact it might be nice to specify an attribute list here using something like type image gif image jpeg That won t work however because attribute lists are restricted to name tokens The forward slash isn t part of the valid set of name token characters so this declaration fails Besides that creating an attribute list in the DTD would limit the valid MIME types to those defined today Leaving it as CDATA leaves things more open ended so that the declaration will continue to be valid as additional types are defined In the document a reference to an image named intro pic might look some thing like this lt image src image intro pic gif alt Intro Pic type image gif gt The Altemative Using Entity References Using a MIME data type as an attribute of an element is a mechanism that is flexible and expandable To create an external ENTITY reference using the nota tion mechanism you need DTD
529. ww naics htm for details e The Universal Standard Products and Services Classification UNSPSC See http www eccma org unspsc for details e The ISO 3166 country codes classification system maintained by the Inter national Organization for Standardization ISO See http www iso org iso en prods ser vices iso3166ma index htm1 for details The following sections describe how to perform some common queries Finding Organizations by Name To search for organizations by name you normally use a combination of find qualifiers which affect sorting and pattern matching and name patterns which specify the strings to be searched The findOrgani zations method takes a col lection of findQualifier objects as its first argument and a collection of name Pattern objects as its second argument The following fragment shows how to find all the organizations in the registry whose names begin with a specified string qString and to sort them in alphabetical order Define find qualifiers and name patterns Collection findQualifiers new ArrayListQ findQualifiers add FindQualifier SORT_BY_NAME_DESC Collection namePatterns new ArrayListQ namePatterns add qString Find using the name BulkResponse response bqm findOrganizations findQualifiers namePatterns null null null null Collection orgs response getCollection A client can use percent signs to specify that the query string can occur any where within t
530. xamples JAXM Translator and JAXM Tags require certain permis sions to be granted in order to run successfully To make these changes perform the following steps 1 Open the following file in an editor lt S1AS7_HOME gt domains domain1 serverl1 config server policy 2 Find the following line permission java util PropertyPermission read 3 Add write permission by changing the line as follows permission java util PropertyPermission read write 325 326 WEB SERVICES MESSAGING WITH JAXM 4 Append the following lines of text to the end of the file The entire string between grant codebase and the opening curly brace should be on one line This permission applies to the privileged jaxm tags webapp grant codeBase file com sun aas instal1Root domains domainl serverl applications j2ee modules permission java util logging LoggingPermission control 35 5 Restart the server instance so the changes will take effect The Requestjava Program The class Request java puts together the code fragments used in the section Client without a Messaging Provider page 302 and adds what is needed to make it a complete example of a client sending a request response message In addition to putting all the code together it adds import statements a main method and a try catch block with exception handling The file Request java shown here in its entirety is a standalone client application that uses the S
531. xists the statement creates the bean and stores it as an attribute of the scope object see Using Scope Objects page 55 The value of the id attribute determines the name of the bean in the scope and the identifier used to reference the bean in other JSP elements and scriptlets Note In JSP Scripting Elements page 95 we mentioned that you must import any classes and packages used by a JSP page This rule is slightly altered if the class is only referenced by useBean elements In these cases you must only import the class if the class is in the unnamed package For example in What Is a JSP Page page 83 the page index jsp imports the MyLocales class However in the Duke s Book store example all classes are contained in packages and thus are not explicitly imported The following element creates an instance of Currency if none exists stores it as an attribute of the session object and makes the bean available throughout the session by the identifier currency lt jsp useBean id currency class util Currency scope session gt Setting JavaBeans Component Properties There are two ways to set JavaBeans component properties in a JSP page with the jsp setProperty element or with a scriptlet lt beanName setPropName value gt SETTING JAVABEANS COMPONENT PROPERTIES The syntax of the jsp setProperty element depends on the source of the prop erty value Table 4 3 summarizes the various ways to set a pro
532. y process ing you can save it as a request attribute The Dispatcher servlet used by a ver sion of the Duke s Bookstore application described in The Example JSP Pages page 114 saves the path information from the original URL retrieves a RequestDispatcher from the request and then forwards to the JSP page tem plate jsp public class Dispatcher extends HttpServlet public void doGet HttpServletRequest request HttpServletResponse response request setAttribute selectedScreen request getServletPathQ RequestDispatcher dispatcher request getRequestDispatcher template jsp if dispatcher null dispatcher forward request response ACCESSING THE WEB CONTEXT 75 public void doPost HttpServletRequest request The forward method should be used to give another resource responsibility for replying to the user If you have already accessed a ServletOutputStream or PrintWriter object within the servlet you cannot use this method it throws an I1legalStateException Accessing the Web Context The context in which Web components execute is an object that implements the ServletContext interface You retrieve the Web context with the getServlet Context method The Web context provides methods for accessing e Initialization parameters e Resources associated with the Web context e Object valued attributes e Logging capabilities The Web context is used by the Duke s Bookstore filters fi ters HitCounter F
533. y to perform database access operations the EJB container handles this for you However if you override the default container managed persistence for any reason you will need to use the JDBC API Also if you choose to have a session bean access the database you have to use the JDBC API JDBC API The JOBC API lets you invoke SQL commands from Java programing lan guage methods You use the JDBC API in an enterprise bean when you override the default container managed persistence or have a session bean access the database With container managed persistence database access operations are handled by the container and your enterprise bean implementation contains no JDBC code or SQL commands You can also use the JDBC API from a servlet or JSP page to access the database directly without going through an enterprise bean The JDBC API has two parts an application level interface used by the applica tion components to access a database and a service provider interface to attach a JDBC driver to the J2EE platform Java Servlet technology Java Servlet technology lets you define HTTP specific servlet classes A servlet class extends the capabilities of servers that host applications accessed by way of a request response programming model Although servlets can respond to any type of request they are commonly used to extend the applications hosted by Web servers JavaServer Pages Technology JavaServer Pages JSP technology lets
534. ynamic invocation interface DID STATIC STUB CLIENT EXAMPLE When you run these client examples they will access the MyHel1loService that you deployed in the preceding section Static Stub Client Example StaticStubHello is a stand alone program that calls the sayHello and say Goodbye methods of MyHe1loService It makes this call through a stub a local object which acts as a proxy for the remote service Because this stub is created before runtime by the IDE it is called a static stub Static SuubHello Source Code Before it can invoke the remote methods on the stub StaticStubHel1o per forms these steps 1 Creates a Stub object named stub return Stub new MyHelloService_Imp1 getMyHel loServiceRPCPortQ The program gets the Stub object by invoking a private method named createProxy Note that the code in this method is implementation spe cific and may not be portable because it relies on the MyHelloService_Imp1 object The MyHelloService_Imp1 class is cre ated by the IDE in when you choose the Generate Client Proxy menu item in Building and Running the StaticStubHello Client page 278 2 Casts stub to the service definition interface MyHel 1oServiceRPC MyHelloServiceRPC hello MyHelloServiceRPC stub A service definition interface declares the methods that a remote client may invoke on the service In this example the interface MyHel1oSer viceRPC defines the sayHello and sayGoodbye methods The IDE cre
535. you put snippets of servlet code directly into a text based document A JSP page is a text based document that JAVA MESSAGE SERVICE contains two types of text static template data which can be expressed in any text based format such as HTML WML and XML and JSP elements which determine how the page constructs dynamic content Java Message Service The Java Message Service JMS is a messaging standard that allows J2EE application components to create send receive and read messages It enables distributed communication that is loosely coupled reliable and asynchronous For more information on JMS see the online Java Message Service Tutorial http java sun com products jms tutorial index htm Java Naming and Directory Interface The Java Naming and Directory Interface JNDI provides naming and direc tory functionality It provides applications with methods for performing standard directory operations such as associating attributes with objects and searching for objects using their attributes Using JNDI a J2EE application can store and retrieve any type of named Java object Because JNDI is independent of any specific implementations applications can use JNDI to access multiple naming and directory services including existing naming and directory services such as LDAP NDS DNS and NIS This allows J2EE applications to coexist with legacy applications and systems For more information on JNDI see the online JNDI Tutor
536. you saved a table component its parameters might be the number of rows and columns to display Archived components can also be shuffled around the Web and used in a variety of ways When components are archived in binary form however there are some limita tions on the kinds of changes you can make to the underlying classes if you want to retain compatibility with previously saved versions If you could modify the archived version to reflect the change that would solve the problem But that s hard to do with a binary object Such considerations have prompted a number of investigations into using XML for archiving But if an object s state were archived in text form using XML then anything and everything in it could be changed as easily as you can say search and replace XML s text based format could also make it easier to transfer objects between applications written in different languages For all of these reasons XML based archiving is likely to become an important force in the not too distant future Summary XML is pretty simple and very flexible It has many uses yet to be discovered we are just beginning to scratch the surface of its potential It is the foundation for a great many standards yet to come providing a common language that dif ferent computer systems can use to exchange data with one another As each industry group comes up with standards for what they want to say computers will begin to link to each oth

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