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jsfjsf-2elcomposite-componentajax4jsf

Using id-attribute in JSF 2 composite component with targets

I am trying to create a JSF 2.1 composite component for a button:

<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:composite="http://java.sun.com/jsf/composite"
xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich"
xmlns:c="http://java.sun.com/jstl/core">

    <composite:interface>
        <composite:attribute name="id" required="true" type="java.lang.String" />
        <composite:attribute name="label" required="true" type="java.lang.String" />
        <composite:attribute name="action" method-signature="java.lang.String action()" targets="#{cc.attrs.id}" />
    </composite:interface>

    <composite:implementation>
        <a4j:commandLink id="#{cc.attrs.id}">
            <span style="linkButton"><h:outputText value="#{cc.attrs.label}" /></span>
        </a4j:commandLink>
    </composite:implementation>
</html>

The problem I have with this code is that it gives the following exception when the page is rendered:

java.lang.ClassCastException: javax.faces.component.UINamingContainer cannot be cast to javax.faces.component.ActionSource2
at com.sun.faces.application.view.FaceletViewHandlingStrategy$MethodRetargetHandlerManager$ActionRegargetHandler.retarget(FaceletViewHandlingStrategy.java:1536)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.retargetMethodExpressions(FaceletViewHandlingStrategy.java:689)
at com.sun.faces.facelets.tag.jsf.CompositeComponentTagHandler.applyNextHandler(CompositeComponentTagHandler.java:201)
at org.richfaces.view.facelets.html.BehaviorsAddingComponentHandlerWrapper.applyNextHandler(BehaviorsAddingComponentHandlerWrapper.java:53)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:196)
...

When I replace the #{cc.attrs.id} in id and targets attribute with a defined String like myId then the component works as expected but this makes it not reusable in the same page and thus eliminates the wohle sense in creating a composite component in the first place.

Did I miss anything here?

Solution

  • In the JSF component tree, the #{cc.attrs.id} is already used by <cc:implementation> itself. You're not supposed to reuse any used component ID on another component. Your concrete functional requirement is unclear, the complaint "not reusable in the same page" makes really no sense as it works perfectly fine (have you actually tried it and investigated the produced HTML output?), so it's hard to understand what problem exactly you're facing. Perhaps you completely overlooked that composite components implicitly inherit from NamingContainer and already prepend their own id to those of children, like as <h:form>, <h:dataTable>, etc also do?

    If your sole requirement is being able to reference the composite component from outside by ajax as in <f:ajax render="compositeId" />, then you need to wrap the body of <cc:implementation> in a plain vanilla HTML <span> or <div> as follows with the #{cc.clientId} instead:

    <div id="#{cc.clientId}">

    See also: