经典多线程问题（六）-零奇偶问题01020304

1.0 countdownlatch关键字的使用

package com.example.demo;

import java.util.concurrent.CountDownLatch;

/**
 * @ClassName ZeroEvenOdd
 * @Description: 1116. 打印零与奇偶数（多线程）
 * @Author xtanb
 * @Date 2019/9/23
 * @Version V1.0
 **/
public class ZeroEvenOdd {
    private int n;
    private CountDownLatch countDownLatchA;
    private CountDownLatch countDownLatchB;
    private CountDownLatch countDownLatchC;

    public ZeroEvenOdd(int n) {
        this.n = n;
        this.countDownLatchA = new CountDownLatch(0);
        this.countDownLatchB = new CountDownLatch(1);
        this.countDownLatchC = new CountDownLatch(1);
    }

    // printNumber.accept(x) outputs "x", where x is an integer.
    public void zero(IntConsumer printNumber) throws InterruptedException {
        for(int i=0;i<n;i++){
            countDownLatchA.await();
            printNumber.accept(0);
            countDownLatchA = new CountDownLatch(1);
            if(i%2==0){
                countDownLatchB.countDown();
            }else{
                countDownLatchC.countDown();
            }
        }
    }

    public void even(IntConsumer printNumber) throws InterruptedException {
        for(int i=1;i<=n;i=i+2){
            countDownLatchB.await();
            printNumber.accept(i);
            countDownLatchB = new CountDownLatch(1);
            countDownLatchA.countDown();
        }
    }

    public void odd(IntConsumer printNumber) throws InterruptedException {
        for(int i=2;i<=n;i=i+2){
            countDownLatchC.await();
            printNumber.accept(i);
            countDownLatchC = new CountDownLatch(1);
            countDownLatchA.countDown();
        }
    }

    public static void main(String[] args) {
        ZeroEvenOdd zeroEvenOdd = new ZeroEvenOdd(10);
        IntConsumer printNumber = new IntConsumer();
        new Thread(){
            @Override
            public void run() {
                try {
                    zeroEvenOdd.zero(printNumber);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();
        new Thread(){
            @Override
            public void run() {
                try {
                    zeroEvenOdd.odd(printNumber);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();
        new Thread(){
            @Override
            public void run() {
                try {
                    zeroEvenOdd.even(printNumber);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }
}