简介

在这里模仿CyclicBarrier,自定义一个自己多线程屏障类，里面有个计时器count，count为0时，才唤醒线程，否则就await挂起，（没错就是用的object类的挂起和唤醒全部线程方法）

1、MyCyclicBarrier

package com.jacky;import java.util.concurrent.BrokenBarrierException;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.ReentrantLock;/** * Created by jacky on 2018/2/11. */public class MyCyclicBarrier {    private int count;    private int parties;    private  Runnable barrierAction;    private final ReentrantLock lock = new ReentrantLock();    private final Condition condition = lock.newCondition();    public MyCyclicBarrier(int parties,Runnable barrierAction){        if (parties <=0){            throw new IllegalArgumentException();        }        this.parties = parties;        this.count = parties;        this.barrierAction = barrierAction;    }    public  int await() throws InterruptedException,BrokenBarrierException {        lock.lock();        try {            int index = --count;            if (index ==0){              if (null == barrierAction){                  barrierAction.run();              }                condition.signalAll();               return  index;            }            for (;;){                 condition.await();                return index;            }        }finally {            lock.unlock();        }    }}

2、测试

package com.jacky;import com.sun.org.apache.xpath.internal.SourceTree;import java.util.concurrent.BrokenBarrierException;import java.util.concurrent.CyclicBarrier;/** * Created by jacky on 2018/2/11. */public class CyclicBarrierDemo {    public static void main(String[] args) throws InterruptedException {        MyCyclicBarrier barrier = new MyCyclicBarrier(3, new Runnable() {            @Override            public void run() {                Thread thread = Thread.currentThread();                System.out.println("barrierAction start"+thread.getName());                try {                    Thread.sleep((int)Math.random()*300);                } catch (InterruptedException e) {                    e.printStackTrace();                }                System.out.println("barrierAction start"+thread.getName());            }        });        Runnable runnable1 = new Runnable() {            @Override            public void run() {                try {                    Thread.sleep((int)(Math.random()*100));                } catch (InterruptedException e) {                    e.printStackTrace();                }                Thread thread = Thread.currentThread();                System.out.println("thread start:"+thread.getName());                try {                    Thread.sleep(1000);                } catch (InterruptedException e) {                    e.printStackTrace();                }                try {                    barrier.await();                } catch (InterruptedException e) {                    e.printStackTrace();                } catch (BrokenBarrierException e) {                    e.printStackTrace();                }                System.out.println("thread end:"+thread.getName());            }        };        Runnable runnable2 = new Runnable() {            @Override            public void run() {                try {                    Thread.sleep((int)(Math.random()*200));                } catch (InterruptedException e) {                    e.printStackTrace();                }                Thread thread = Thread.currentThread();                System.out.println("thread start:"+thread.getName());                try {                    Thread.sleep(2000);                } catch (InterruptedException e) {                    e.printStackTrace();                }                try {                    barrier.await();                } catch (InterruptedException e) {                    e.printStackTrace();                } catch (BrokenBarrierException e) {                    e.printStackTrace();                }                System.out.println("thread end:"+thread.getName());            }        };        Thread thread1 = new Thread(runnable1);        Thread thread2 = new Thread(runnable2);        Thread thread3 = new Thread(runnable1);        thread1.start();        thread2.start();        thread3.start();        Thread.sleep(2000);        System.out.println("thread1:"+thread1.getName()+","+thread1.getState());        System.out.println("thread2:"+thread2.getName()+","+thread2.getState());        System.out.println("thread3:"+thread3.getName()+","+thread3.getState());    }}