者_察_观

/**
* 被观察者对象
*/
public class Observable
{
private boolean chanaged = false;

private Vector<Object> obs;

public Observable()
{
obs = new Vector<Object>();//创建一个同步列表，保存所有的观察者
}

public void chuangge()
{
System.out.println("选手“aaa”开始唱歌..."); //$NON-NLS-1$
}

/**
* 添加观察者到列表中
* @param o
*/
public synchronized void add(Observer o)
{
if (o != null)
{
if (!obs.contains(o))
{
obs.addElement(o);
}
}
}

/**
* 通知操作，传递一个参数到观察者那里，进行操作
* @param obj
*/
public void notifyObservers(Object obj)
{
Object[] arrayLocal = obs.toArray();
for (int i = arrayLocal.length - 1; i >= 0; i--)
{
Object object = arrayLocal[i];
if (object instanceof Observer)
{
Observer os = (Observer)object;
os.update("sss");
}
}
}

public static void main(String[] args)
{
Observable observable = new Observable();

ObsInstance1 obsInstance1 = new ObsInstance1();
ObsInstance2 obsInstance2 = new ObsInstance2();

observable.add(obsInstance1);
observable.add(obsInstance2);

observable.chuangge();
}
}

/**
* 观察者接口
*/
interface Observer
{
public int update(Object obj);
}
/**
* 观察者一
*/
public class ObsInstance1 implements Observer
{
@Override
public int update(Object obj)
{
System.out.println("评委一，你唱的太难听了。。。"); //$NON-NLS-1$
return 60;
}
}
/**
* 观察者二
*/
public class ObsInstance2 implements Observer
{
@Override
public int update(Object obj)
{
System.out.println("评委二，你长的太丑了。。。"); //$NON-NLS-1$
return 61;
}
}