信号灯法_解决生产者消费者问题

添加一个标志位

代码：

package multithreading.Advanced;

public class TestPC2 {
    public static void main(String[] args) {
        TV tv = new TV();
        new Player(tv).start();
        new Watcher(tv).start();
    }
}

// 生产者-->演员
class Player extends Thread{
    TV tv;
    public Player(TV tv){
        this.tv = tv;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            if (i%2 == 0){
                this.tv.play("快乐大本营");
            }else {
                this.tv.play("我是歌手");
            }
        }
    }
}

// 消费者-->观众
class Watcher extends Thread{
    TV tv;
    public Watcher(TV tv){
        this.tv = tv;
    }

    @Override
    public void run() {
        for (int i = 0; i < 20; i++) {
            tv.watch();
        }
    }
}

// 产品-->节目
class TV{
    // 演员表演，观众等待
    // 观众观看，演员等待
    String voices;  // 表演的节目
    boolean flag = true;

    // 表演
    public synchronized void play(String voices){
        if (!flag){
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("演员表演了："+voices);
        // 通知观众观看
        this.notifyAll();
        this.voices = voices;
        this.flag = !this.flag;
    }

    // 观看
    public synchronized void watch(){
        if (flag){
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("观看了："+voices);
        // 通知演员表演
        this.notifyAll();
        this.flag = !this.flag;
    }
}