JSF2.0 - Composite component with optional method expression

composite-component, java-ee-6, jsf-2

Solution

You will have to create two `p:commandLink` elements and render them conditionally according to definition of your parameter:

<p:commandLink actionListener="#{cc.attrs.actionMethod}" rendered="#{!empty cc.getValueExpression('actionMethod') and cc.attrs.showComponent}">
  <h:outputText value="#{cc.attrs.namePrompt}"/>
</p:commandLink>
<p:commandLink rendered="#{empty cc.getValueExpression('actionMethod')}">
  <h:outputText value="#{cc.attrs.namePrompt}"/>
</p:commandLink>

Problem

I'm implementing a composite component and I found a issue which I didn't find a solution. I specified its attributes that can or not be passed by the page author, but I couldn't specify a method attribute (a method expression to Action) that, if it wasn't passed, the composite component doesn't use the method attribute in the composite:implementation tag. Here my code: ``` <composite:interface> <composite:attribute name="namePrompt" required="true"/> <composite:attribute name="actionMethod" method-signature="java.lang.String action()" required="false"/> <composite:attribute name="showComponent" default="false"/> </composite:interface> <composite:implementation> <div> <p:commandLink actionListener="#{cc.attrs.actionMethod}" rendered="#{cc.attrs.showComponent}" > <h:outputText value="#{cc.attrs.namePrompt}"/> </p:commandLink> </div> </composite:implementation> ``` When using it, I didn't specify the "actionMethod" attribute. Like this: ``` <util:foo namePrompt="SomeName" showComponent="true"/> ``` But I get the error message: ``` javax.faces.FacesException: Unable to resolve composite component from using page using EL expression '#{cc.attrs.actionMethod}' ``` Is there a way to do this?

Original source