JUC（2）使用condition实现精准通知唤醒

package com.orderPC;

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

/**
 * 执行A，然后B，然后C，然后A
 */

public class ProductC {
    public static void main(String[] args) {
        Data3 data3 = new Data3();
        new Thread(()->{
            for (int i = 0; i <5 ; i++) {
                data3.printA();
            }

        },"A").start();
        new Thread(()->{
            for (int i = 0; i < 5; i++) {
                data3.printB();

            }
        },"B").start();
        new Thread(()->{
            for (int i = 0; i < 5; i++) {
                data3.printC();

            }
        },"C").start();
    }
}

//资源类
class Data3{
    private Lock lock = new ReentrantLock();
    Condition condition1 = lock.newCondition();
    Condition condition2 = lock.newCondition();
    Condition condition3 = lock.newCondition();
    private int num = 1;

    public void printA(){
        lock.lock();
        try {
            while(num != 1){
                //等待
                condition1.await();
            }
            System.out.println(Thread.currentThread().getName()+"-->AAA");
            num=2;
            //唤醒，唤醒指定的
            condition2.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }
    public void printB(){
        lock.lock();

        try {
            while(num !=2 ){
                condition2.await();
            }
            System.out.println(Thread.currentThread().getName()+"-->BBB");
            num =3;
            //唤醒指定线程
            condition3.signal();

        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }
    public void printC(){
        lock.lock();

        try {
            while(num != 3){
                //等待
                condition3.await();
            }
            System.out.println(Thread.currentThread().getName()+"-->CCC");
            num = 1;
            condition1.signal();

        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }

}