Notes by Fang

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Created by Fang on March 30, 2012 10:07:25    Last update: March 30, 2012 10:09:08
After a user resets a password, I want to force the user to change the password before she gets access to secured content. This is usually done with a servlet filter. But with Spring MVC, you can also use a HandlerInterceptor . According to Spring JavaDoc: HandlerInterceptor is basically similar to a Servlet 2.3 Filter, but in contrast to the latter it just allows custom pre-processing with the option of prohibiting the execution of the handler itself, and custom post-processing. Filters are more powerful, for example they allow for exchanging the request and response objects that are handed down the chain. Note that a filter gets configured in web.xml, a HandlerInterceptor in the application context. As a basic guideline, fine-grained handler-related preprocessing tasks are candidates...
Created by Fang on March 05, 2012 20:32:37    Last update: March 05, 2012 20:32:37
In this simple example, I create a simple validating bean and create a JUnit test to test the validation. The bean ( src/main/java/com/example/Person.java ): package com.example; import javax.validatio... The test ( src/test/java/com/example/TestPerson.java ): package com.example; import java.util.Set; ... Run the test: mvn clean test You'll notice that one test passed and the other failed. The tests require that a person must have a name and the name cannot be empty, so @NotNull is not the right rule to use here. To make sure that the name is not empty, we need to use @Pattern . But since a null String matches any pattern, @NotNull is also needed: package com.example; import javax.validatio...
Created by Fang on February 10, 2012 14:41:03    Last update: February 10, 2012 14:44:01
I wanted to add a jar file to a Maven project but I don't want to create an artifact and install it to the repository. This is a third party jar that will be used only for this project and not shared with other projects, so it's convenient just to drop it in the project folder and package it with the target. Maven provides the system dependency scope to do just that: <dependency> <groupId>com.thirdparty</group...
Created by Fang on November 21, 2011 16:30:56    Last update: December 07, 2011 08:54:32
This is a series of notes on building custom JSF 2.0 facelet taglibs, ordered from the simplest to the less simple. Hopefully it can help you to get started on how to build custom taglibs for JSF. A simple JSF facelets taglib example The simplest taglib I can think of. Using EL expression with a custom tag Make tag attributes dynamic. Mixing custom tag with facelet ui taglibs Discover things you might run into when you get into more details. Which EL context to use? Using the wrong EL context can lead to subtle bugs. JSF facelet taglib backed by a UI component A UIComponent can be a tag handler, without being TagHandler . Using tag handler, UI component and renderer with a JSF facelet...
Created by Fang on November 21, 2011 15:57:49    Last update: November 22, 2011 09:51:26
The improved custom taglib works with existing facelet ui taglibs. For example: <ui:param name="theName" value="John"/> <my:hel... produces the expected output. However, a problem exists with the ui:repeat tag: <h3>With ui:repeat</h3> <ui:repeat var="theName... When tested with a URL like: http://localhost:8080/facelet-demo/?name=Zack&name... the raw EL prints out the correct names, but my custom tag substitutes empty string for theName2 ! In theory, the response is rendered in the Render Response phase, way after the Apply Request Values phase, actual values should be available to EL. The answer to this anomaly turned out to be very deep ! Yes, right there in the code! I would consider this a bug in facelets implementation, but the JSF spec did not tell what the expected behavior should be. In my custom...
Created by Fang on November 21, 2011 13:49:11    Last update: November 21, 2011 13:49:11
In the test for the simple taglib example , I used a literal string for the name attribute: <my:hello name="Jack"/> What happens if the name attribute contains EL expresson? For example: <my:hello name="#{param['name']}"/> If EL works, the tag should take the value of the " name " request parameter and print it out. But the tag as implemented in the simple taglib example prints the literal string: Hello #{param['name']}! I am FaceletTag. In order to make a tag to recognize EL, we have to use TagAttribute.getValue(FaceletContext ctx) instead of TagAttribute.getValue() . The latter returns the literal value of the attribute. The HelloTagHandler should be changed to: package com.example; import java.io.IOExcep... Rebuild the taglib and test with a URL like this: http://localhost:8080/facelet-test/?name=Jack The tag will print:...
Created by Fang on November 10, 2011 09:26:12    Last update: November 10, 2011 09:26:12
Syntax highlighted XML schema for JSF 2.0 Application Configuration Resource File ( faces-config.xml ). Almost 3000 lines! <?xml version="1.0" encoding="UTF-8"?> <xsd:sch...
Created by Fang on September 07, 2009 20:44:15    Last update: November 03, 2011 14:43:19
Step 1: Repackage a web app as EAR A Java EE application is a multimodule Maven project. At the very least you'll need to package a WAR and an EAR. To get started, I'll simply re-package the simple webapp as an EAR. Create a directory named javaee-app Copy the webapp from here to javaee-app . Rename struts1app to webapp . Create pom.xml under javaee-app : <project> <modelVersion>4.0.0</modelVersion>... Create a directory named ear under javaee-app . Create pom.xml under ear : <project> <modelVersion>4.0.0</modelVersion>... Modify pom.xml in the webapp directory so that it looks like this: <project> <modelVersion>4.0.0</modelVersion> ... Build with " mvn package " in the javaee-app directory. You can see that ear-1.0.ear is successfully generated in javaee-app/ear/target . Maven successfully resolves dependencies between the sub-projects....
Created by Fang on October 31, 2011 21:10:10    Last update: October 31, 2011 21:13:10
In this example I'll add a parameter to a facelets template. The example contains three tabs, each tab points to a different page. The tab control is shared among all pages, therefore, it is put in the template. Starting from the simple facelet example , make these additions: Create a new template WEB-INF/templates/tabs.xhtml : <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Stric... Add a page for the about tab ( about.xhtml ): <?xml version="1.0" encoding="UTF-8"?> <ui:comp... Add a page for the news tab ( news.xhtml ): <?xml version="1.0" encoding="UTF-8"?> <ui:comp... Add a page for the partner tab ( partner.xhtml ): <?xml version="1.0" encoding="UTF-8"?> <ui:comp... Build and re-deploy the application. Launch the browser and load page http://localhost:8080/facelet-demo/about.jsf . This is a screenshot:
Created by Fang on October 28, 2011 14:49:53    Last update: October 28, 2011 14:52:19
Facelet templates can be nested, for example, a page can use a template which inherits from another template. To demonstrate this, let's start from the simple example and make these additions: Add a place holder for CSS style sheets in WEB-INF/templates/default.xhtml : <h:head> <title>Facelets Template Demo</tit... Add a derivative template ( WEB-INF/templates/default-style.xhtml ) which provides CSS: <?xml version="1.0" encoding="UTF-8"?> <ui:comp... Add a page that uses the styled template ( home-style.xhtml ): <?xml version="1.0" encoding="UTF-8"?> <ui:comp... The only difference between this file and home.xhtml is the template being used. Compare the display of the pages home.xhtml and home-style.xhtml .
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