我可以在复合组件中的bean上调用方法吗? [英] Can I call methods on beans in composite components?

问题描述

我想编写一个或多或少的gemeric组件，在该组件中，我将提交一个控制器bean，并且组件应显示一些CRUD按钮.

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.

以下复合组件:

<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";
}

当我单击取消"按钮时，

导致以下异常:

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)

不可能在提供给CC的bean上调用方法吗?

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

推荐答案

可以.您的错误只是您仅传递了一个普通香草String，它代表托管Bean名称为属性值

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"

您实际上应该已经从EL范围传递了具体的托管bean实例

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

controller="#{customerController}"

诚然，异常消息在某种程度上具有误导性，但它基本上只是显示属性值的Object#toString().如果它是一个具体的托管bean实例，您宁愿看到类似

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

未找到方法:[e-mail]()

Method not found: [e-mail]()

或它的toString()实现返回的任何内容(如果被覆盖).

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

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