看了下观察者模式。。。是用C++写的，然后回到java，看到Obserable简直喜不自胜啊

从客户端开始：

	@Test
	public void testObserver(){
		NumObserverable observable = new NumObserverable();//被观察者
		NumObserv	er observer1 = new NumObserver();//观察者
		Observer observer2 = new ODDOberser();//观察者
		Observer observer3 = new EvenOberser();//观察者
		
		observable.addObserver(observer2);//
		observable.addObserver(observer3);
		observable.addObserver(observer1);
		
		observable.setData(5);
	}

 

NumObserverab类

public class NumObserverable extends Observable{
	public static final Integer EVEN = 2;
	public static final Integer ODD = 1;
	private int data = 0;

	public int getData() {
		return data;
	}

	public void setData(int data) {
		this.data = data;
		Integer flag = EVEN;
		if((data&0x00001) == 1){
			flag = ODD;
		}
		setChanged();
		notifyObservers(flag);
	}
	
}

ODDObserver类

public class ODDOberser implements Observer{
	public void update(Observable o, Object arg) {
		if(arg == NumObserverable.ODD){
			System.out.println("NumOberserale发生奇数设置："+((NumObserverable)o).getData());
		}
		
	}
}

EvenObserver类

public class EvenOberser implements Observer{
	public void update(Observable o, Object arg) {
		if(arg == NumObserverable.EVEN){
			System.out.println("NumOberserale发生偶数设置："+((NumObserverable)o).getData());
		}
		
	}
}