设计模式 观察者模式

首先写秘书类

import java.util.ArrayList;
import java.util.List;

public class Secretary {

	private List<StockObserver> observers=new ArrayList<StockObserver>();
	
	private String action;
	
	public String getAction() {
		return action;
	}

	public void setAction(String action) {
		this.action = action;
	}

	public void Attach(StockObserver observer)
	{
		observers.add(observer);
	}
	
	public void Notify()
	{
		for (StockObserver stockObserver : observers) {
			stockObserver.Update();
		}
	}
	
	
}

在写观察者类

public class StockObserver {

	private String name;
	private Secretary sub;
	public StockObserver(String name,Secretary sub)
	{
		this.name=name;
		this.sub=sub;
	}
	public void Update()
	{
		System.out.println(sub.getAction()+"!!!"+name+"关闭股票行情，继续工作！");
	}
}

在写测试类

public class Program {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Secretary secretary=new Secretary();
		StockObserver worker1 = new StockObserver("施于任", secretary);
		StockObserver worker2 = new StockObserver("魏国冲", secretary);
		
		//登记着两位工友
		secretary.Attach(worker1);
		secretary.Attach(worker2);
		
		//发现老板回来
		secretary.setAction("老板回来了");
		
		//通知两个同事
		secretary.Notify();
	}

}