JUC生产者消费者指定唤醒

JUC生产者消费者指定唤醒

使用不同的condition，调用signal()

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class Demo {
    public static void main(String[] args) {
        Data data = new Data();

        // 线程A
        new Thread(() -> { for (int i = 0; i < 10; ++i) data.printA();}).start();
        // 线程B
        new Thread(() -> { for (int i = 0; i < 10; ++i) data.printB();}).start();
        // 线程C
        new Thread(() -> { for (int i = 0; i < 10; ++i) data.printC();}).start();
    }
}

// 资源类
class Data {
    // Lock对象
    private Lock lock = new ReentrantLock();
    // 监视器
    private final Condition conditionA = lock.newCondition();
    private final Condition conditionB = lock.newCondition();
    private final Condition conditionC = lock.newCondition();
    // 条件
    private int num = 0;
    // 当num==0时执行A
    // 当num==1时执行B
    // 当num==2时执行C

    // 方法A
    public void printA(){
        // 上锁
        lock.lock();
        try {
            // 等待
            while (num != 0){
                conditionA.await();
            }
            // 业务
            System.out.println("A");
            // 通知B
            num = 1;
            conditionB.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }

    // 方法B
    public void printB(){
        // 上锁
        lock.lock();
        try {
            // 等待
            while (num != 1){
                conditionB.await();
            }
            // 业务
            System.out.println("B");
            // 通知C
            num = 2;
            conditionC.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }
    // 方法C
    public void printC(){
        // 上锁
        lock.lock();
        try {
            // 等待
            while (num != 2){
                conditionC.await();
            }
            // 业务
            System.out.println("C");
            // 通知A
            num = 0;
            conditionA.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 解锁
            lock.unlock();
        }
    }

}