小编Eri*_*ves的帖子

我正在实现一个复合组件,我发现了一个我找不到解决方案的问题.

我指定了页面作者可以传递或不传递的属性,但我无法指定方法属性(Action的方法表达式),如果未传递,则复合组件不使用method属性在composite:implementation标签中.

这是我的代码:

<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>

使用它时,我没有指定"actionMethod"属性.像这样:

<util:foo namePrompt="SomeName" showComponent="true"/>

但我收到错误消息:

javax.faces.FacesException: Unable to resolve composite component from using page using EL expression '#{cc.attrs.actionMethod}'

有没有办法做到这一点？

我正在研究Java认证1Z0-803,我对垃圾收集存在疑问:

import java.util.*;

class X {
    List<String> list = new ArrayList<>();
}

public class TestGC {
    // Is an Object eligible for GC even if its instance variable is references to another variable
    public static void main(String[] args){
        X x = new X(); // 1
        List<String> list = x.list;
        x = null; // 2, Is X object reference eligible for garbage collection here?

        list.add("a");
        list.add("b");
        list.add("c");

        for(String item : list) {
            System.out.println(item);
        }
        list = null;// 3, Or X object …