Java多线程中的CyclicBarrier使用方法详解

public class Solver {
    final int N;
    final float[][] data;
    final CyclicBarrier barrier;
    volatile boolean over = false;
    public Solver(float[][] matrix) throws InterruptedException {
        data = matrix;
        N = matrix.length;
        //每一轮循环都会执行，并且需要run执行完才会触发下一轮开启.
        Runnable barrierAction =
                new Runnable() {
                    @Override
                    public void run() {
                        System.out.println("Solver.run");
                        over = true;
                    }
                };
        //初始化CyclicBarrier
        barrier = new CyclicBarrier(N, barrierAction);
        List<Thread> threads = new ArrayList<>(N);
        for (int i = 0; i < N; i++) {
            Thread thread = new Thread(new Worker(i));
            threads.add(thread);
            thread.start();
        }
        // wait until done
        for (Thread thread : threads) {
            thread.join();
        }
    }
    //程序入口
    public static void main(String[] args) throws InterruptedException {
        float[][] matrix = {{1.2F}, {2.2F}};
        Solver solver = new Solver(matrix);
    }
    class Worker implements Runnable {
        int myRow;
        Worker(int row) {
            myRow = row;
        }
        @Override
        public void run() {
            while (!done()) {
                processRow(myRow);
                try {
                    barrier.await();
                } catch (InterruptedException | BrokenBarrierException ex) {
                    return;
                }
            }
        }
        private void processRow(int myRow) {
            System.out.println("Worker.processRow:" + myRow);
        }
        private boolean done() {
            return over;
        }
    }
}

 if (barrier.await() == 0) {
   // log the completion of this iteration
 }

CyclicBarrier(int parties, Runnable barrierAction) 
//添加线程在屏障达到时触发！线程会阻塞下一轮开始直到该线程执行完毕。

int getParties()  //获取当前设置的屏障数

int await()       //等待直到所有线程执行await达到屏障数

int await(long timeout, TimeUnit unit)  //等待直到所有线程执行await达到屏障数或者超过指定超时时间

boolean isBroken()   //查询当前屏障是否处于broken状态

void reset()         //重置当前屏障数到初始时数量

int getNumberWaiting() //查询当前等待未到达屏障值的线程数