java 多線程-信號燈法

借助標志位

public class light {
public static void main(String[]args)
{
    Tv tv=new Tv();
    new Player(tv).start();
    new Watcher(tv).start();
}

}
//生產(chǎn)者 演員
class Player extends Thread{
Tv tv;
public Player(Tv tv)
{
    this.tv=tv;
}
public void run()
{
    for(int i=0;i<20;i++)
    {
        if(i%2==0)
        {
            this.tv.play("偶不變");
        }else
        {
            this.tv.play("奇變");
        }
    }
}
}
//消費者 觀眾
class Watcher extends Thread{
Tv tv;
public Watcher(Tv tv)
{
    this.tv=tv;
}
public void run()
{
    for(int i=0;i<20;i++)
    {
        this.tv.watch("無聊");
    }
}
}
//同一個資源 電視
    class Tv {

String voice;
//信號燈
//為真則演員表演，觀眾等待
//為假則觀眾觀看，演員等待

boolean flag=true;

//表演
public synchronized void play(String voice)
{
    if(!flag)
    {
        try {
            this.wait();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    System.out.println("表演了:"+voice);
    this.voice=voice;

    //表演后
    this.notifyAll();
    this.flag=!this.flag;
}

public void watch(String string) {
    // TODO Auto-generated method stub

}

//觀看
public synchronized void watch()
{
    if(flag)
    {
        try {
            this.wait();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    System.out.println("聽到了:"+voice);

    //觀看后:
    this.notifyAll();
    this.flag=!this.flag;
}
}