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jsfjsf-2childrencomposite-component

In JSF2, how to know if composite component has children?

I'm writing a composite component, you have a special tag named:

<composite:insertChildren />

Which inserts all the component's children there. Is there any way to know whether the component has children? Like a boolean value that could go on a "rendered" attribute.

Solution

  • The basic expression you're after is the following:

    #{cc.childCount} or more elaborately:

    #{component.getCompositeComponentParent(component).childCount}

    E.g. the following composite component:

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

    <cc:implementation>             
        <h:outputText value="Children: #{cc.childCount}" />
    </cc:implementation>    
</html>

    used on the following Facelet:

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

    <h:body>

        <test:myCom>
            <h:outputText value="first child" />
            <h:outputText value="second child" />
        </test:myCom>

    </h:body>
</html>

    will print Children: 2.

    Thus #{cc.childCount != 0} will tell you whether a composite component has children or not.