Java并发编程中的Exchanger解析

    // 等待另一个线程到达此交换点（除非当前线程被中断），然后将给定的对象传送给该线程，并接收该线程的对象。
    public V exchange(V x) throws InterruptedException
    //增加超时机制，超过指定时间，抛TimeoutException异常
    public V exchange(V x, long timeout, TimeUnit unit) throws InterruptedException, TimeoutException

class FillAndEmpty {
    Exchanger<DataBuffer> exchanger = new Exchanger<DataBuffer>();
    DataBuffer initialEmptyBuffer = ... a made-up type
    DataBuffer initialFullBuffer = ...
    
    //填充缓冲区线程
    class FillingLoop implements Runnable {
        public void run() {
            DataBuffer currentBuffer = initialEmptyBuffer;    //空的缓冲区
            try {
                while (currentBuffer != null) {
                    addToBuffer(currentBuffer);    //填充数据
                    //如果缓冲区被数据填满，执行exchange。等待清空缓冲区线程也执行exchange方法。当两个线程都到达同步点，交换数据。
                    if (currentBuffer.isFull())
                        currentBuffer = exchanger.exchange(currentBuffer);    
                }
            } catch (InterruptedException ex) { ... handle ... }
        }
    }
    
    //清空缓冲区线程
    class EmptyingLoop implements Runnable {
        public void run() {
            DataBuffer currentBuffer = initialFullBuffer;    //满的缓冲区
            try {
                while (currentBuffer != null) {
                    takeFromBuffer(currentBuffer);    //清空缓冲区
                    //如果缓冲区被清空，执行exchange。等待填充缓冲区线程也执行exchange方法。当两个线程都到达同步点，交换数据。
                    if (currentBuffer.isEmpty())
                        currentBuffer = exchanger.exchange(currentBuffer);
                }
            } catch (InterruptedException ex) { ... handle ...}
        }
    }
 
    void start() {
        new Thread(new FillingLoop()).start();
        new Thread(new EmptyingLoop()).start();
    }
}