EventListenerList 实例

package com.hexun.sample;
import javax.swing.event.EventListenerList; 
import java.util.Date; 
import java.text.DateFormat; 
import java.text.SimpleDateFormat;

/** 
* Java的事件机制/自定义事件.

运行结果: 
do something interesting in source here. 
listener detects [event]:wintys.event.MyEvent[source=wintys.event.MySource@18158 
59] [occur at]:2009-10-11 16:27:49 
listener detects [event]:wintys.event.MyEvent[source=wintys.event.MySource@18158 
59] [occur at]:2009-10-11 16:27:49

* @version 2009-10-11 
* @author 天堂露珠 ([e-mail]) 
* @see http://www.blogjava.net/wintys 
*/ 
public class MyEventTest{ 
    public static void main(String[] args){ 
        MySource source = new MySource(); 
        MyListener myListener = new MyListener(){ 
            public void doMyAction(MyEvent e){ 
                System.out.println("listener detects " + e); 
            } 
        }; 
        source.addMyListener(myListener); 
        source.addMyListener(myListener); 
        source.addMyListener(myListener); 
        source.removeMyListener(myListener);

        source.doSomething(); 
    } 
}

/** 
* 自定义的事件. 
* @version 2009-10-11 
* @author 天堂露珠([e-mail]) 
* @see http://www.blogjava.net/wintys 
*/ 
class MyEvent extends java.util.EventObject{ 
    private Date date;//记录事件发生的时间

    public MyEvent(Object source , Date date){ 
        super(source);

        this.date = date; 
    }

    public String toString(){ 
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
        String dt = df.format(date);

        return "[event]:" + super.toString() + " [occur at]:" + dt; 
    } 
}

/** 
* 自定义事件监听器接口. 
* @version 2009-10-11 
* @author 天堂露珠([e-mail]) 
* @see http://www.blogjava.net/wintys 
*/ 
interface MyListener extends java.util.EventListener{ 
    void doMyAction(MyEvent e); 
}

/** 
* 自定义事件源. 
* @version 2009-10-11 
* @author 天堂露珠([e-mail]) 
* @see http://www.blogjava.net/wintys 
*/ 
class MySource{ 
    /** 
     * 保存注册的监听器列表. 
     * 子类可以使用它保存自己的事件监听器(非MyListener监听器)列表. 
     */ 
    protected EventListenerList listenerList = new EventListenerList(); 
    private MyEvent myEvent = null;//fireDoMyAction()使用此变量

    /** 
     * 没有做任何事 
     */ 
    public MySource(){ 
    } 
    /** 
     * 添加一个MyListener监听器 
     */ 
    public void addMyListener(MyListener listener){ 
        listenerList.add(MyListener.class , listener); 
    }

    /** 
     * 移除一个已注册的MyListener监听器. 
     * 如果监听器列表中已有相同的监听器listener1、listener2, 
     * 并且listener1==listener2, 
     * 那么只移除最近注册的一个监听器。 
     */ 
    public void removeMyListener(MyListener listener){ 
        listenerList.remove(MyListener.class , listener); 
    }

    /** 
     * @return 在此对象上监听的所有MyListener类型的监听器 
     */ 
    public MyListener[] getMyListeners(){ 
        return (MyListener[])listenerList.getListeners(MyListener.class); 
    }

    //Winty:Copy directly from javax.swing.event.EventListenerList 
    /*Notify all listeners that have registered interest for 
       notification on this event type. The event instance 
       is lazily created using the parameters passed into 
       the fire method. 
     */ 
    protected void fireDoMyAction() { 
         // getListenerList() Guaranteed to return a non-null array 
         Object[] listeners = listenerList.getListenerList(); 
         // Process the listeners last to first, notifying 
         // those that are interested in this event 
        for (int i = listeners.length-2; i>=0; i-=2) { 
            if (listeners[i]==MyListener.class) { 
                // Lazily create the event: 
                if (myEvent == null) 
                    myEvent = new MyEvent(this , new Date()); 
                ((MyListener)listeners[i+1]).doMyAction(myEvent); 
            } 
        } 
    }

    /** 
     * 做一些事件源应该做的有意义的事，然后通知监听器. 
     * 这里只是一个示例方法. 
     * 例如:MySource如果是一个按钮，则doSomething()就可以命名为click(), 
     * 当用户点击按钮时调用click()方法. 
     */ 
    public void doSomething() { 
        System.out.println("do something interesting here.");

        fireDoMyAction();//通知监听器 
    } 
}
http://apps.hi.baidu.com/share/detail/18575799