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					Facelets
Çağatay Çivici Apache MyFaces Team Member cagatay@apache.org

Çağatay Çivici
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Apache MyFaces Project Committer OpenLogic Expert Group Member Sourceforge jsf-comp project developer JSF Client Side Validators Acegi Security Framework’s JSF Components JFreeChart for JSF : JSF Chart Creator FacesTrace: Visual Debugger of JSF

Agenda
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JSF and JSP Facelets Jsfc and inline texts Templating Composition Components EL Functions JSTL Support Custom Logic Tags

JSF and JSP
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JSP is the default view technology JSP tags refer to JSF components
h:commandButton = HtmlCommandButton Mixing them brings overhead because of two different lifecycles
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JSF and JSP (Advantages)
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JSP is well adopted, reduces learning curve of JSF. Above is the only advantage

JSF and JSP (Disadvantages)
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JSP is created to generate dynamic output not to create component trees Two different lifecycles (overhead) Content Interweaving Issues

JSF and JSP
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JSF 1.1 - Initial request (e.g. index.jsf)
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FacesServlet gets the request and JSF lifecycle begins restoreState returns null and a new view is created (createView) with view id = index.jsp (jsp is the default suffix) lifecycle jumps to renderResponse renderView is called that dispatches index.jsp to the container Container traverses all the tags, tags call component’s encode methods during component tree is created State is saved via writeState and buffered output is rendered to the client.

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JSF 1.2 - a servletwrapper is used instead of f:view to buffer the content and component tree is created before rendering

Facelets
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A viewhandler purely created for JSF No more JSP .xhtml instead of .jsp No tld files and no tag classes to defined a UIComponent Faster than using JSP&JSF

Migrating from JSP to Facelets
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<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h"%> <%@ taglib uri="http://java.sun.com/jsf/core" prefix="f"%>

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<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core">

Installation
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Add jsf-facelets.jar to the classpath Add viewhandler config to faces-config.xml Change javax.faces.DEFAULT_SUFFIX to .xhtml

*.taglib.xml
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Concept similar to tld but lightweight Used to define components, converters, validators, composition components, custom logic tags, functions and etc.

Jsfc
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Jsfc : jwcid concepty in Tapestry
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<h:commandButton id=“btn_save” value=“Save” action=“#{bean.method}” /> <input jsfc="h:commandButton" type="submit" id=“btn_save" value=“Save“ action=“#{bean.method}”/>

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Provides integration with HTML editors

Inline Texts
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Inline Text: Display texts without a UIComponent
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<h:outputText value=“#{IndexPageBean.welcomeMessage}” /> <h1>#{IndexPageBean.welcomeMessage}</h1>

Support for Unified EL
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Facelets support the Unified EL #{BeanName.field} same as; ${BeanName.field}

Templating
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A template is an xhtml with placeholders Placeholders are marked with ui:insert
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Fragment from Template.xhtml <title> <ui:insert name="title">Default Title</ui:insert> </title>

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In order to use the template ui:composition is needed.
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Fragment from index.xhtml
<ui:composition template="/template.xhtml"> <ui:define name="title"> Welcome to index page </ui:define>

Composition Components
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Composition component is basically a template userInfo.xhtml
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<ui:composition xmlns:ui="http://java.sun.com/jsf/facelets"> <h3>Logged as : #{user}</h3> </ui:composition> <tag> <tag-name>userInfo</tag-name> <source>tags/userInfo.xhtml</source> </tag>

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myfacelets.taglib.xml
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Use as;
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<ds:userInfo user="#{myBean.currentUser}"/>

EL Functions
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MyFunctions.java
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public static String length(String name) { if( name == null ) return null; else return String.valueOf( name.length() );

}
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myfacelets.taglib.xml
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<function> <function-name>length</function-name> <function-class>faceletsbox.utils.CustomerUtils</function-class> <function-signature> java.lang.String length(java.lang.String) </function-signature> </function>

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Use as;
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#{ds:length(MyBean.userName)}

JSTL Support
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With JSP, mixing JSF and JSTL is problematic Facelets brings limited but faultless support
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<c:if> <c:forEach> <c:catch> <c:set>

Custom logic tags
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JSTL like logic tags by extending Facelets TagHandler myfacelets.taglib.xml
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<tag> <tag-name>if</tag-name> <handler-class>mycompany.myproject.utils.IfHandler</handler-class> </tag>

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Use as;
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<ds:if test="#{MyBean.isLoggedIn}"> Welcome </ds:if>

List of built-in Facelets tags
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<ui:component/> <ui:composition/>  <ui:debug/>  <ui:decorate/> <ui:define/> <ui:fragment/> <ui:include/> <ui:insert/> <ui:param/> <ui:remove/> <ui:repeat/>

Summary
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Facelets saves JSF from the burden of JSP Great for templating and composition components plus bonuses like el functions IDE support is not wide, only Exadel support facelets for now

The End – Questions?
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cagatay@apache.org www.jroller.com/page/cagataycivici