###事件处理 与c#中的委托相似，Java中事件的原型就是observer设计模式。

代码示例1：

interface WaterOkListener{
	void actionWaterOk();	
}

class Water{
	java.util.List<WaterOkListener>waterOk =new java.util.ArrayList<WaterOkListener>();
	
	//绑定事件
	public void addWaterOkListener(WaterOkListener sender){
		waterOk.add(sender);
	}
	//取消绑定
	public void removeWaterOkListener(WaterOkListener e){
		waterOk.remove(e);
	}

	//触发事件
	public void waterOk(){
		
		System.out.println("水开了！");
		for(int i=0;i<waterOk.size();i++){
			waterOk.get(i).actionWaterOk();	
		}	
	}
}
class Zhangsan implements WaterOkListener{

	public void actionWaterOk(){
		System.out.println("张三去提水去了！！");	
	}
}
class Lisi implements WaterOkListener {
	
	public void actionWaterOk(){
		System.out.println("李四去提水去了！");	
	}	
}

class waterTest{
	public static void main(String[]args){
		Lisi f=new Lisi();
		Zhangsan z=new Zhangsan();
		Water w=new Water();
		w.addWaterOkListener(f);
		w.addWaterOkListener(z);
		w.waterOk();	
	}
}

代码示例2：

package java事件;

import java.util.*;


//最简单的事件

interface WakenUpListener
{
	void actionWakenUp();
}

class Child
{
	private boolean wakeUp = false;
	private List<WakenUpListener> wakenUp = new ArrayList<WakenUpListener>();

	public void addActionListener(WakenUpListener w)
	{
		wakenUp.Add(w);
	}
	public void removeActionListener(WakenUpListener e)
	{
		wakenUp.Remove(e);
	}

	public void wake()
	{
		System.out.println("小孩醒了！");
		for (int i = 0; i < wakenUp.size(); i++)
		{
			wakenUp.get(i).actionWakenUp();
		}
	}
}

class Father implements WakenUpListener 
{
	public void actionWakenUp()
	{
		System.out.println("喂小孩东西吃！");
	}
}
class GrandFather implements WakenUpListener 
{
	public void actionWakenUp()
	{
		System.out.println("抱小孩出去玩！");
	}
}
class Dog implements WakenUpListener
{
	public void actionWakenUp()
	{
		System.out.println("汪汪汪...");
	}
}


class test
{
	public static void main(String[] args)throws Exception 
	{
		Dog d = new Dog();
		Father f = new Father();
		GrandFather g = new GrandFather();
		Child c = new Child();
		c.addActionListener(d);
		c.addActionListener(f);
		c.addActionListener(g);
		Thread.sleep(200);
		c.wake();
		c.removeActionListener(d);
		c.wake();
	}
}