Can I call methods on beans in composite components?

问题

I want to write a more or less gemeric component, where i hand in a controller bean and the componend should display some CRUD buttons.

Following composite component:

<composite:interface>
  <composite:attribute name="controller" />
  <composite:attribute name="object" />
</composite:interface>

<composite:implementation>

  <h:panelGrid columns="3" columnClasses="celltop">
    <h:commandButton id="save" value="#{msg.saveButtonLabel}"
      action="#{cc.attrs.controller.save}" />
    <h:commandButton id="delete" value="#{msg.deleteButtonLabel}"
      action="#{cc.attrs.controller.delete(cc.attrs.object)}" />
    <h:commandButton id="cancel" value="#{msg.backButtonLabel}"
      action="#{cc.attrs.controller.cancel}" immediate="true" />
  </h:panelGrid>

</composite:implementation>

<viewController:buttons controller="customerController" object="#{customerController.customer}"/>

@Named
@ConversationScoped
public class CustomerController implements Serializable {

    public String cancel() {
    customer = null;
    if (!conversation.isTransient()) {
        conversation.end();
    }
    return "cancelled";
}

leads to the following exception when I click on the Cancel button:

javax.faces.el.MethodNotFoundException: javax.el.MethodNotFoundException: /resources/components/viewController/buttons.xhtml @25,65 action="#{cc.attrs.controller.cancel}": Method not found: customerController.cancel()
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:92)

Is it not possible to call methods on beans given to CC?

回答1:

Yes you can. Your mistake is just that you passed only a plain vanilla String representing the managed bean name as attribute value

controller="customerController"

while you should actually have passed the concrete managed bean instance from the EL scope

controller="#{customerController}"

The exception message is admittedly somewhat misleading, but it's basically just showing the Object#toString() of the attribute value. If it were a concrete managed bean instance, you'd rather have seen something like

Method not found: com.example.CustomerController@12345678.cancel()

or whatever is been returned by its toString() implementation, if overridden.

来源：https://stackoverflow.com/questions/11994339/can-i-call-methods-on-beans-in-composite-components

标签

jsf-2

composite-component