package com.artisan.test;
import java.util.stream.Stream;
public class MultiProduceConsumerDemo2 {
    // 对象监视器-锁
    private final Object LOCK = new Object();
    // 是否生产出数据的标识
    private boolean isProduced = false;
    // volatile 确保可见性， 假设 i 就是生产者生产的数据
    private volatile int i = 0;
    public void produce() {
        synchronized (LOCK) {
            String msg = isProduced ? "已生产货物" : "没有货物可搬运";
            // while 每次被唤醒时都会先检查isProduced是否滿足條件再继续
            // 不能用if的原因：if它将不再判断isProduced是否滿足條件，直接继续，引发错误
            // 举个例子 t1 ,t2 都进入到了wait ,然后使用if, 唤醒了t2后，不再判断isProduced是否滿足條件
            // 直接又生产了一个，导致生产多了数据
            while (isProduced) {
                try {
                    System.out.println(Thread.currentThread().getName() + " GOT LOCK ,isProduced= " + isProduced + " wait becauseof  " + msg);
                    LOCK.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            i++;
            System.out.println(Thread.currentThread().getName() + " GOT LOCK ,isProduced= " + isProduced + " Produce:" + i);
            // 唤醒所有正在等待这个对象的monitor的线程
            LOCK.notifyAll();
            isProduced = true;
        }
    }
    public void consume() {
        // 加锁
        synchronized (LOCK) {
            String msg = isProduced ? "已生产货物" : "没有货物可搬运";
            // while 每次被唤醒时都会先检查isProduced是否滿足條件再继续
            while (!isProduced) {
                try {
                    System.out.println(Thread.currentThread().getName() + " wait becauseof  " + msg);
                    LOCK.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(Thread.currentThread().getName() + " GOT LOCK ,isProduced= " + isProduced + " Consume:" + i);
            //唤醒所有正在等待这个对象的monitor的线程
            LOCK.notifyAll();
            isProduced = false;
        }
    }
    public static void main(String[] args) {
        MultiProduceConsumerDemo2 produceConsumerDemo = new MultiProduceConsumerDemo2();
        Stream.of("P1", "P2").forEach(n -> new Thread(n) {
            @Override
            public void run() {
                while (true) produceConsumerDemo.produce();
            }
        }.start());
        Stream.of("C1", "C2").forEach(n -> new Thread(n) {
            @Override
            public void run() {
                while (true) produceConsumerDemo.consume();
            }
        }.start());
    }
}