ComposerMVC User Guide - Index of
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1. Version 1 0 26 05 2004 Page 11 112. service does not receive an output DOM containing the result view name the Controller forwards the request with any error messages if present to the Error view JSP 9 The result view JSP uses static HTML normal JSP actions tags and the Composer tag library to take the result DOM from the web service and render it in the result HTML page If this page also contains an HTML Form and the user presses submit in this form then the whole flow cycle is repeated again 10 lf the error pages is forwarded to the error page displays a generic message and if any error messages are passed to it displays theses as well again using static HTML normal JSP syntax and Composer tags 2 2 Inputs and Outputs Typically a JSP which contains a HTML Form for submission to a ComposerMVC application will contain HTML source similar to the following lt FORM METHOD POST ACTION orders gt lt INPUT TYPE hidden NAME Controller VALUE ordersController gt lt INPUT TYPE hidden NAME Action VALUE searchAction gt lt P gt Surname lt INPUT TYPE text NAME LastName gt lt P gt lt P gt Account Id lt INPUT TYPE text NAME Account gt lt P gt lt P gt lt INPUT TYPE submit NAME search VALUE Search gt lt P gt lt FORM gt This example shows an order lookup form where the user is expected to enter his her last name and account id to be able to lookup his her existing orders In the ComposerMVC project the main controller JSP
3. ComposerMVC User Guide ComposerMVC User Guide By Paul Done Version 1 0 26 05 2004 Page 1 11 ComposerMVC User Guide 1 Introduction ComposerMVC is Model View Controller MVC framework for use in exteNd Composer projects Typically Novell s exteNd Composer product is used by developers to create web services which represent an organisation s processes These services usually encapsulate data and logic which already exist in one or more back end systems The user interface for Composer developed web services are normally constructed using other products and programming languages These products are used to consume the Composer web services For example an exteNd Director portal a C NET GUI application or a JZEE web application Since version 5 0 exteNd Composer has provided native capabilities for creating simple HTML interfaces using the Java Server Pages JSP technology However on its own this capability is fairly limited and if used forces the developer to embed large sections of Java code scriptlets within the Composer JSPs Validation inter page navigation and linking is also very difficult to achieve using Composer JSPs The ComposerMVC framework introduces the MVC design pattern http java sun com blueprints patterns MVC html to a Composer project to try to eliminate some of these shortcomings A ComposerMVC project can be divided into the three logical sections Model the normal Composer Web Services th
4. E experience the team does not posses licenses for exteNd Director the preferred UI creation toolkit for Composer web services the team is creating an HTML web application using mostly static or content managed pages and only a small part of the application needs to dynamically generate content Note This document assumes that the reader already has a familiarity with Novell s exteNd Composer product Version 1 0 26 05 2004 Page 2 11 ComposerMVC User Guide 2 Framework Structure 2 1 Control Flow The diagram below shows the basic structure of a ComposerMVC project In a Composer project the Container JSP and Web Service parts of the Controller are pre supplied and do not need to be created or modified The only part of the Controller requiring development effort is the creation of the individual Action components XML Map components which respond to HTML Form submissions Page 1 Page 2 Page 3 JSP JSP JSP View View View Key Blue Model Grey View Yellow Controller The typical flow of control for deployed ComposerMVC projects is 1 Via a browser an end user access the URL of the main controller JSP Container JSP 2 The main controller JSP determines that for this user the first view should automatically be shown and forwards the request straight to the Page 1 JSP view to generate a HTML page 3 The result HTML page typically contains an HTML Form which includes two special hidden input items Cont
5. at integrate with back end systems View a set of standard Composer JSPs displaying a mix of static HTML and dynamically generated HTML via the standard Composer Tag Library Controller a special container JSP a special controller web service and a set of action XML Map components The benefits of the ComposerMVC framework are developers build web services in the normal way enabling these web services to subsequently be used remotely and unchanged if a future decision is made to move to a full user interface toolkit such as exteNd Director later on in a project s lifetime normal JSPs contain no scriptlet code and only use HTML standard JSP syntax and Composer s standard tag library to dynamically generate pages thus reducing the overhead of page creation and maintenance all validation logic for HTML Form submission calls to update or query the model and navigation logic to determine what view to display is implemented in individual action components where programmatic logic is most easily accomplished in Composer The ComposerMVC framework is NOT a replacement for a fully fledged user interface toolkit such as exteNd Director Ideally such toolkits should be used given sufficient skills resources and licenses However this is not an ideal world hence this framework can provide a service to a development team which falls into one of the following three categories e the team has little or no Java J2E
6. d including MySQL and the samples50 database the phonelist table in this database is used by the project The project provides a simple 3 stage page flow enabling a user to i search for a person by last name or email address ii view the search results and select one person to view details for iii view the selected persons full details To open and run this project unzip the project to the filesystem and open the project s SPF file using the Composer Designer Before the project can be run it may be necessary to change the database connection details for the samples50 MySQL database From the Composer Designer open the Connections SamplesDB object and ensure that the JDBC URL user and password fields are set correctly the password is assumed to be admin by default To run the project select the Composer deploy option and either deploy the project to the default exteNd application Server profile or create and choose a new profile for another server eg Tomcat Once deployed the application can be run from a browser via the URL mvcdemo index html eg http localhost mvcdemo index html Version 1 0 26 05 2004 Page 10 11 ComposerMVC User Guide A Appendix A 1 Licence All source code binary releases and documentation which constitute the ComposerMVC project are covered by the following open source BSD style licence Copyright c 2004 Paul Done All rights reserved Redistribution and use
7. ically used by the framework to temporarily store the previously returned web service output DOM on the user s session object View JSPs can be arbitrarily named However experience has shown that prefixing the jsp name with the name of the application helps organise the project better For example for an orders application instead of calling the search JSP search it should be called orders_ search Action components can also be arbitrarily named However experience has shown that suffixing the component name with the word Action helps to distinguish action components from the regular XML Map components in a project For example for an orders application instead of calling the search action component SearchComponent it should be called searchAction The controller JSP and web service naming conventions specified in steps 1 and 2 above MUST be adhered to otherwise the framework will not be able to link the two together and the project variables listed in step 3 will not be located by the controller Composer provides a set of Tag Library tags which can be executed from a JSP These are described in the main Composer documentation C Program FilesiNovellexteNd5aiDocsiStart Composer Help html Select Composer User s Guide Select The Composer Tag Library These tags include e value e forEach hasnovalue e hasvalue e if execute To supplement the normal HTML tags JSP tags and Composer tags developer
8. in source and binary forms with or without modification are permitted provided that the following conditions are met Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution Neither the name ComposerMVC nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission HIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF ERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL HE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF HIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
9. mporary DOM eg Temp which can be free form no template or may use the same input template that is used by the normal web service that will be called Include validation logic eg Condition actions Script etc to validate that the input DOM content is correct and if not set the target view and error message elements of the Metadata output DOM accordingly using map actions Map elements of the input DOM to the temporary DOM in the format which will be expected by the model web service to be called Version 1 0 26 05 2004 Page 7 11 ComposerMVC User Guide Use the Component Execute action to invoke the normal web service Map the temporary DOM to the input of the service and map the output of the service straight to the Action component s output DOM Using a Map action set the TargetView element of the output Metadata DOM to the literal name of the JSP to be shown next 7 Ensure that all JSPs both the Controller JSP and the View JSPs are included in an application s Deployment profile with appropriate URLs specified Notes The ComposerMVC framework provides a category of templates called MVC This contains the input template ControllerInput and the metadata output MetadataOutput template which are used by the Controller Web Service and each Action Component The framework provides an ECMAScript library called ServletAPI This can be used to invoke various Servlet related APIs and is specif
10. or JSP is used to show the error messages Alternatively it is perfectly acceptable for the target view element to be set by the Action component the the name of original search JSP In this case the search JSP can show the error messages on the same page as the offending input items thus enabling the end user to re submit with correct data For this example if the validation was successful and the web service returned an Output DOM containing the account details and metadata DOM with the orders results JSP set as the target view the orders results JSP could have the following example content to show the results lt H1 gt Account Details lt H1 gt lt P gt First Name lt composer value name data xpath Account FirstName gt lt P gt lt P gt Last Name lt composer value name data xpath Account LastName gt lt P gt lt composer forEach name data xpath Account Addresses Address gt lt P gt Postcode lt composer value xpath Postcode gt lt composer forEach gt and alternatively if any errors were returned in the metadata a special error JSP or even a normal error JSP could display the errors in a manner similar to the following lt P gt The input data was invalid please try again lt P gt lt composer hasvalue name data part Metadata xpath MetadataOutput Errors gt lt composer forEach name data part Metadata xpath MetadataOutput Errors gt lt P gt Error lt composer value xpath Me
11. ordersController_FirstView Value orders search Name ordersController_ErrorView Value orders_errorpage 4 At the top of each View JSP include the following two lines to ensure that the Composer Tag Library is defined and the output and metadata DOMs from the main Controller web service are available to use in the JSP lt taglib uri composer prefix composer gt lt pageContext setAttribute data request getAttribute data gt 5 In each View JSP that will contain an HTML Form include two hidden parameters to enable the Controller to be used correctly when a form submit event occurs These items should specify the name of the Controller web service and the name of the target Action component respectively For example lt INPUT TYPE hidden NAME Controller VALUE ordersController gt lt INPUT TYPE hidden NAME Action VALUE searchAction gt 6 An Action component will usually be required for each View JSP that contains an HTML Submit Form to respond to the JSP s submit event An Action component should have the following structure The Input DOM should use the MVC Controllerinput XML template The Output DOM can be free form no template or use the same output template that is used by the normal web service that will be called by this component An extra output DOM should be added and called Metadata and this should use the MVC MetadataOutput XML template e Create a single te
12. ow Help HO F xX BEHG Y R xx Novell Input Data Ox ib Temp Output Metadata E lt gt ROOT B lt gt MetadataOutput lt gt Controller myappController lt gt Targetview myapp_showresults lt gt Action searchAction E lt gt Errors lt gt LastName Bloggs lt gt Message lt gt Account 4734834 lt gt Message S E SEa il ESsearch ction B T IF Input XPath ROOT LastName amp amp Input XPath ROOT Account E TRUE 3 MAP Input ROOT TO Temp Accounts x Execute GetAccountDetails Pass Temp Return Out T IF Out XPath count AccountiLastName lt 0 E TRUE Ss MAP Selection returned no data try again TO Metadata MetadataOutputErrors Message amp MAP myapp search TO Metadata MetadataOutputTargetview FALSE Ss MAP myapp_showresults TO Metadata MetadataOutput TargetView E FALSE Ss MAP You did not specify a last name and account id try again TO Metadata MetadataOutputErrors Message Ss MAP myapp search TO Metadata MetadataOutput Targetview E Version 1 0 26 05 2004 Page 9 11 ComposerMVC User Guide 4 MVC Demo Application A sample project called mvcdemo is provided to demonstrate how the ComposerMVC project can be used in practice This project can also be used as the basis of any new ComposerMVC project rather than using the skeleton composermvc project if preferred This project assumes that the full exteNd Enterprise suite is installe
13. roller name and Action name in addition to normal HTML input items and submit buttons 4 The user enters some data and presses submit which sends the HTTP Post request back to the URL of the controller JSP 5 The controller JSP uses the two hidden parameters Controller name and Action name to determine which custom Action component to call and invokes the Action component passing the input DOM which contains all the submitted input items 6 The Action XML Map component converts the input DOM to the format required by the web service s it will call validates that all correct input parameters for the web service are present and then invokes the web service with the modified DOM 7 Once the web service has completed the Action component checks the result output DOM from the web service and then identifies which result view JSP should be shown as a result passing this back to the calling Controller web service The Action component also checks for any errors which may have occurred in the called web service Any error messages generated are also placed in its output DOMs for use by the Controller web service Version 1 0 26 05 2004 Page 3 11 ComposerMVC User Guide 8 If the output DOMs received by the Controller web service from the Action component contains the name of a View JSP to show the Controller web services then forwards the request to the result view JSP along with the output DOM If the Controller web
14. s may also find that the JSP Standard Tag Library JSTL http java sun com products jsp jstl helps in the authoring of View JSPs To incorporate this Tag Library just include the JSTL jar files in the Composer project and the appropriate taglib directive at the top of each JSP which will use the JSTL tags Instead of hard coding the target URL fora HTML Form submit the following JSP Version 1 0 26 05 2004 Page 8 11 ComposerMVC User Guide expression can be used to ensure that each View JSP always posts back to the main controller JSP lt FORM METHOD POST ACTION lt request getRequestURI gt gt If required view JSPs can still pull data directly from the model by using the Composer execute tag to execute a named web service e lt A HREF gt hyperlinks can also be generated in a page to call the controller JSP when selected provided that the hyperlink URL parameters include the special Controller and Action parameters The Controller Web Service will treat HTML Form POST submits and HTML hyperlink GET requests in the same way assembling all the input parameters into an input DOM 3 2 Example Action component Below is a screenshot of an example Action component called searchAction which would be used to invoke an account search web service given a user s last name and account id fel exteNd Composer mycdemo XML Map searchAction HER File Edit View Component Action Animate Tools Wind
15. ssage gt lt P gt lt composer forEach gt lt composer hasvalue gt Observe that in the three example JSPs orders_search orders_showresults and orders_errorpage only standard HTML tags standard JSP syntax and the Composer Standard Tag Library are used Also the normal web services in the model take a normal single input DOM and return a normal single output DOM and are thus not directly tied into the ComposerMVC framework structure Version 1 0 26 05 2004 Page 6 11 ComposerMVC User Guide 3 Starting a New Project 3 1 Steps To use the ComposerMVC framework in an exteNd Composer 5 0 project either unzip and copy the skeleton composermvc project or choose to create a new empty project and import the relevant Xobjects from the skeleton composermvc project into the new project The following list describes all the elements which need to be included in a project to incorporate the ComposerMVC framework 1 Rename the main Container Controller JSP called myapp to the name of the application it is required for eg orders 2 Rename the main Controller Web Service called myappController to the same name as the controller JSP suffixed by the word Controller eg ordersController 3 Select the Tools Project Settings menu option in the Composer Designer and add two new project variables to specify the name of the first page and the error page respectively for the application For example Name
16. tName gt lt LastName gt Bloggs lt LastName gt lt Addresses gt lt Address gt lt House gt 32 lt House gt lt Street gt Sea Avenue lt Street lt Town gt Sunny town lt Town gt lt Postcode gt ST2 1AZ lt Postcode gt lt Address gt lt Address gt lt House gt ACME House lt House gt lt Street gt ACME Park lt Street lt Town gt Grey City lt Town gt lt Postcode gt GC1 1BB lt Postcode gt lt Address gt lt Addresses gt lt Account gt and the metadata DOM may have the following content lt MetadataOutput gt lt TargetView gt orders showresults lt TargetView gt lt Errors gt lt MetadataOutput gt however if there was a validation error or normal web service error there may be an empty output DOM and the metadata DOM may have the following content lt MetadataOutput gt lt TargetView gt orders errorpage lt TargetView gt lt Errors gt lt Message gt An account last name has not been specified lt Message gt lt Message gt An account first name has not been specified lt Message gt lt Errors gt lt MetadataOutput gt The TargetView element of the metadata DOM tells the main controller JSP which normal view JSP should be forwarded to The Errors elements of the metadata data DOM is stores any error Version 1 0 26 05 2004 Page 5 11 ComposerMVC User Guide messages which need to be displayed to the user In the example where the validation error occurred a separate err
17. will be associated with the web application URL orders When invoked the Controller JSP uses the standard Composer execute tag to invoke the Controller Web Service which will receive this input DOM in the following format lt ROOT gt lt Controller gt ordersController lt Controller gt lt Action gt searchAction lt Action gt lt LastName gt Bloggs lt LastName gt lt Account gt 8437393 lt Account gt lt submit gt Search lt submit gt lt ROOT gt The controller web service is then able to invoke the Action Component XML Map called searchAction Using the standard Composer map instructions this Action Component converts the input DOM into the DOM format required by the proper web service to be called For example lt AccountSearch gt lt LastName gt Bloggs lt LastName gt lt Account gt 8437393 lt Account gt Version 1 0 26 05 2004 Page 4 11 ComposerMVC User Guide lt AccountSearch gt The output of both an Action Component and the Controller Web Service is actually two DOMs i a normal output DOM and ii a special metadata DOM The output DOM can contain anything and just reflects the output of the normal web service called from the model The metadata DOM has a special structure used by the Controller Web Services and Action Components For this example the output DOM originally from the normal model web service may be similar to the following lt Account gt lt FirstName gt Joe lt Firs
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