Recent Notes
Displaying keyword search results 1 - 10
Created by zhidao on April 25, 2012 14:56:38
Last update: April 25, 2012 14:56:38
Lacking better alternatives, this is how I render a global validation error:
<spring:bind path="changePasswordForm">
<c:if ...
<form:errors> without path attribute seems to work too:
<form:errors cssClass="ui-error"/>
Created by Fang on January 28, 2012 13:24:09
Last update: January 28, 2012 13:31:22
This is a simple JSP custom tags library with tag body. Just like the JSF counterpart , it splits a string and repeats the body for each word, i.e., with this markup:
<%@ taglib uri="http://custom.tag.com/demo" prefix...
output:
<html>
<body>
<p>Hello Tigger!</p>
<p>H...
With Maven, this is the directory structure:
./src
./src/main
./src/main/resources
./s...
There are three files to write:
pom.xml :
<project xmlns="http://maven.apache.org/POM/4.0.0"...
src/main/java/tagdemo/IterateTag.java :
package tagdemo;
import java.io.IOException...
src/main/resources/META-INF/demotag.tld :
<?xml version="1.0" encoding="UTF-8"?>
<!DO...
Build with:
mvn clean install
To use it as a dependency in other Maven projects:
<dependency>
<groupId>tag-demo</groupId>
...
Created by Fang on January 04, 2012 09:54:05
Last update: January 04, 2012 09:54:05
There are two ways to validate a form with JSF: jsf validation on the page with <f:validate...> tags (for example: <f:validateLength> , <f:validateRegex> , etc.), or JSR303 bean validation. This note is about how to customize messages for JSR303 bean validation. The validation message is specified in the message attribute for each validation annotation type. The mesage attribute is not a literal string, but a string that is interpolated in various ways. For example, the default validation message for AssertFalse is {javax.validation.constraints.AssertFalse.message} , which is replaced with the corresponding string in ValidationMessages.properties (or ValidationMessages_tr.properties , ValidationMessages_es.properties , depending on the locale). This is the contents of ValidationMessages.properties in the hibernate validator reference implementation:
javax.validation.constraints.AssertFalse.message =... To customize the messages, just provide the new value in...
Created by Fang on November 10, 2011 13:19:13
Last update: December 01, 2011 19:10:43
You can add custom implicit variables to JSF pages by using a custom EL resolver, in two simple steps: Write an ELResolver class to resolve the variable Add the ELResolver to faces-config.xml Starting from the Maven Hello World example: Add faces API and EL dependencies to pom.xml :
<dependencies> <dependency> <groupId>o... Add a simple greeter class ( src/main/java/com/example/Greeter.java ): package com.example; public class Greeter {... Add our custom EL resolver ( src/main/java/com/example/ELResolver.java ): package com.example; import java.util.Itera... Add the custom EL resolver to src/main/resources/META-INF/faces-config.xml <?xml version="1.0" encoding="UTF-8"?> <faces-c... Build JAR with mvn package Drop the JAR into WEB-INF/lib of a webapp and test the new EL with: <h:outputText value="#{Greeter.sayHi('Mike')}"/> Fixed: the setValue method used to throw an exception, which is wrong. @Override public void setValue(ELContext ctx, O......
Created by Fang on November 22, 2011 10:40:16
Last update: November 22, 2011 10:40:16
This is an example that uses tag handler, UI component and renderer together to support a custom taglib. The main purpose is to show how these components play together.
The tag renders
<ui:param name="extra" value="el interpreted"/>
...
as
<h3>my:foreach</h3>
<ul class="css class" extra...
These are the files:
The tag handler ( src/main/java/com/example/ForeachTagHandler.java ):
package com.example;
import java.util.Map;
...
The UI component ( src/main/java/com/example/UIForeach.java ):
package com.example;
import java.io.IOExcep...
The renderer ( src/main/java/com/example/ForeachRenderer.java ):
package com.example;
import java.io.IOExcep...
Faces config ( src/main/resources/META-INF/faces-config.xml ):
<?xml version="1.0" encoding="UTF-8"?>
<faces-c...
Taglib config ( src/main/resources/META-INF/foreach.taglib.xml ):
<?xml version="1.0" encoding="UTF-8"?>
<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 14, 2011 20:50:51
Last update: November 22, 2011 09:06:10
This facelet fragment will never print anything:
<ui:repeat var="person" value="#{myBean.theJTeam}"... because the test condition always returns false, even though the person var is not null. The same happens even when I define another variable with ui:param : <ui:repeat var="person" value="#{myBean.theJTeam}"... What's happening? The c:if test condition is evaluated before the ui:repeat tag had a chance to set the value! Both facelet ui tags and JSTL c tags are evaluated at the Render Response phase of the JSF lifecycle. But within the Render Response cycle, there are two sub-phases (so to speak): the first builds the UI element tree, the second renders the UI tree. The JSTL c:if tag is evaluated when the tree is built, but the facelet ui:repeat tag is evaluated when the UI...
Created by Fang on November 08, 2011 20:55:00
Last update: November 21, 2011 18:19:44
In the simple taglib example , I used a tag handler class to implement a taglib. This is an example to implement a taglib with a UI component. The purpose is to use a custom tag to split a string and print each part in a separate paragraph, i.e., print
<p>john</p> <p>steve</p> <p>mike</p> with custom tag <my:foreach> : <my:foreach var="who" value="john steve mike"> ... These are the files: pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0"... src/main/java/com/example/UIForeash.java : package com.example; import java.io.IOExcep... src/main/resources/META-INF/faces-config.xml : <?xml version="1.0" encoding="UTF-8"?> <faces-c... src/main/resources/META-INF/foreach.taglib.xml : <?xml version="1.0" encoding="UTF-8"?> <facelet... How to use: Put the JAR file generated by the above project in the WEB-INF/lib folder of the web app. If the web app is a Maven project, just add the taglib project as a dependency:...
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...
