Observer

package observer;

import java.util.Observable;
import java.util.Observer;
/**
* observer
* @author new
*
*/
public class Friend implements Observer{
private String name;

/**
* 朋友的姓名
* @param name
*/
public Friend(String name)
{
this.name=name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

/**
* 获取被观察者的更改信息
*/
  public void update(Observable o,Object arg)
  {
  if(arg instanceof Long){
          System.out.println(name+"已经知道你的手机号码改为："+arg);
      }

  }
 
 
 
}



package observer;

import java.util.Observable;
/**
* 角色被观察者
* @author new
*
*/
public class ObserverDesignPattern extends Observable{

public ObserverDesignPattern()
{
super();
addFriend(new Friend("Tom"));
addFriend(new Friend("Jerry"));

}

//增加观察者
public void addFriend(Friend n)
{
super.addObserver(n);
}

  public void modifyPhoneNumber(final long l)
  {
  setChanged();
  notifyObservers(new Long(l));
    //更改通知观察者
  }

 
 
  public static void main(String[] args) {
      ObserverDesignPattern op = new ObserverDesignPattern();
      //更改手机号码
      System.out.println("我手机号码更改为000000000000");
      op.modifyPhoneNumber(Long.parseLong("000000000000"));
  }

}