生产者消费者模型

生产者消费者模型的特点：

保证生产者不会在缓冲区满的时候继续向缓冲区放入数据，而消费者也不会在缓冲区空的时候，消耗数据。

当缓冲区满的时候，生产者会进入休眠状态，当下次消费者开始消耗缓冲区的数据时，生产者才会被唤醒，开始往缓冲区中添加数据；当缓冲区空的时候，消费者也会进入休眠状态，直到生产者往缓冲区中添加数据时才会被唤醒。

import lombok.extern.slf4j.Slf4j;
import java.util.concurrent.TimeUnit;


public class ProducerAndConsumerDemo {

    public static void main(String[] args) {

        Store store = new Store(10);

        new Thread(new Producer(store), "producer").start();
        new Thread(new Consumer(store), "consumer1").start();
        new Thread(new Consumer(store), "consumer2").start();
    }
}


@Slf4j
class Store {

    private Integer capacity;
    private Integer count = 0;

    public Store(Integer capacity) {
        this.capacity = capacity;
    }

    public Boolean isFull() {
        return this.count >= this.capacity;
    }

    public Boolean isEmpty() {
        return this.count <= 0;
    }

    synchronized void produce() throws InterruptedException {

        if (this.isFull()) {

            log.info("仓库满了，停止生产");
            wait();

        } else if (this.isEmpty()) {

            log.info("仓库空了, 放入第" + count + "号位置，并通知消费者");
            this.count++;
            TimeUnit.SECONDS.sleep(1);
            notifyAll();

        } else {

            log.info("放入第" + count + "号位置");
            this.count++;
            TimeUnit.SECONDS.sleep(1);

        }

    }

    synchronized void consume() throws InterruptedException {

        if (this.isEmpty()) {

            log.info("仓库空了，停止消费");
            wait();

        } else if (this.isFull()) {

            this.count--;
            log.info("仓库满了，取出第" + count + "号位置, 并通知生产者");
            TimeUnit.SECONDS.sleep(2);
            notifyAll();

        } else {

            this.count--;
            log.info("取出第" + count + "号位置");
            TimeUnit.SECONDS.sleep(2);

        }
    }
}

class Producer implements Runnable {

    private Store store;

    public Producer(Store store) {
        this.store = store;
    }

    @Override
    public void run() {

        while (true) {
            try {
                store.produce();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

class Consumer implements Runnable {

    private Store store;

    public Consumer(Store store) {
        this.store = store;
    }

    @Override
    public void run() {
        while (true) {
            try {
                store.consume();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}