How to create a composite component for a datatable column?
Given this datatable (naturally working):
<rich:dataTable var="var" value="#{values}">
<rich:column>
<f:facet name="header">
HEADER
</f:facet>
<h:outputText value="#{var}" />
</rich:column>
</rich:dataTable>
If I define a custom component (also ok in the syntax and at the right place under resources/components):
<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich"
xmlns:composite="http://java.sun.com/jsf/composite">
<!-- INTERFACE -->
<composite:interface>
<composite:attribute name="val" />
</composite:interface>
<!-- IMPLEMENTATION -->
<composite:implementation>
<rich:column>
<f:facet name="header">
HEADER
</f:facet>
<h:outputText value="#{cc.attrs.val}" />
</rich:column>
</composite:implementation>
</html>
Why does the following does not work?
<?xml version="1.0" encoding="UTF-8"?>
<ui:composition template="/WEB-INF/templates/default.xhtml"
xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich"
xmlns:my="http://java.sun.com/jsf/composite/components">
<ui:define name="content">
<rich:dataTable var="var" value="#{values}">
<my:mycolumn val="#{var}"/>
</rich:dataTable>
</ui:define>
</ui:composition>
Do you know how could I let it work (I want to define my own column and save code)? Thanks a lot! Bye
Answer
The <my:mycolumn> element must be an instance of UIColumn as that's the only valid child of a UIData component during the render response phase. All other UIComponent types will be ignored, thus not rendered. A composite component is implicitly a UINamingContaner component, which isn't a UIColumn and therefore ignored.
A PrimeFaces <p:dataTable> with a backing component that extends UIColumn also won't work due to the wrong lifecycle of a composite component. The column has to be created during the view build time, while the composite component's body is created during view render time.
The solution is to create a tag file instead, which means an extra .taglib.xml file, yet it works flawlessly.
/WEB-INF/tags/column.xhtml:
<ui:composition
xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:rich="http://richfaces.org/rich">
<rich:column>
<f:facet name="header">HEADER</f:facet>
<h:outputText value="#{val}" />
</rich:column>
</ui:composition>
/WEB-INF/my.taglib.xml:
<?xml version="1.0" encoding="UTF-8"?>
<facelet-taglib
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facelettaglibrary_2_0.xsd"
version="2.0">
<namespace>http://example.com/my</namespace>
<tag>
<tag-name>column</tag-name>
<source>tags/column.xhtml</source>
<attribute>
<description>Column value</description>
<name>val</name>
</attribute>
</tag>
</facelet-taglib>
Note: The <attribute> entries are not mandatory, but are nice for documentation purposes, such as generated docs and IDE autocomplete.
/WEB-INF/web.xml:
<context-param>
<param-name>javax.faces.FACELETS_LIBRARIES</param-name>
<param-value>/WEB-INF/my.taglib.xml</param-value>
</context-param>
Usage:
<ui:composition
xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:rich="http://richfaces.org/rich"
xmlns:my="http://example.com/my">
<rich:dataTable value="#{values}" var="value">
<my:column val="#{value}" />
</rich:dataTable>
</ui:composition>