Exchanger简单示例

A synchronization point at which threads can pair and swap elements within pairs. Each thread presents some object on entry to the exchange method, matches with a partner thread, and receives its partner's object on return. An Exchanger may be viewed as a bidirectional form of a SynchronousQueue. Exchangers may be useful in applications such as genetic algorithms and pipeline designs.

 Exchanger<V>  V为可以交换的对象的类型；
 Exchanger 它提供一个同步点，用于进行线程间成对配对及交换数据，两个线程通过exchange方法交换数据，如果第一个线程先执行exchange方法，它会一直等待第二个线程也执行exchange，当两个线程都到达同步点时，这两个线程就可以交换数据，将本线程生产出来的数据传递给对方。因此使用Exchanger的重点是成对的线程使用exchange()方法，当有一对线程达到了同步点，就会进行交换数据。因此该工具类的线程对象是成对的。

public class Exchange_Thread {

	public static void main(String[] args) {
		ExecutorService executorSer = Executors.newCachedThreadPool();
		final Exchanger<String> exchanger = new Exchanger<String>();
		executorSer.execute(new Runnable() {
			String data = "Lebron James";
			public void run() {
				System.out.println(Thread.currentThread().getName() + "请在交易截止日前交易走:"+ data);
				try {
					Thread.sleep((long)(Math.random()*100));
					String data1 = (String) exchanger.exchange(data);
					System.out.println(Thread.currentThread().getName() + "交易得到:"+ data1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		});
		
		executorSer.execute(new Runnable() {
			String data = "Anderson, Gerdon and some cash";
			public void run() {
				System.out.println(Thread.currentThread().getName() + "请在交易截止日前交易走:"+ data);
				try {
					Thread.sleep((long)(Math.random()*100));
					String data1 = (String) exchanger.exchange(data);
					System.out.println(Thread.currentThread().getName() + "交易得到:"+ data1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		});
		
		executorSer.execute(new Runnable() {
			String data = "Stephen Curry";
			public void run() {
				System.out.println(Thread.currentThread().getName() + "请在交易截止日前交易走:"+ data);
				try {
					Thread.sleep((long)(Math.random()*100));
					String data1 = (String) exchanger.exchange(data);
					System.out.println(Thread.currentThread().getName() + "交易得到:"+ data1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		});
		
	executorSer.execute(new Runnable() {
			String data = "Paul George";
			public void run() {
				System.out.println(Thread.currentThread().getName() + "请在交易截止日前交易走:"+ data);
				try {
					Thread.sleep((long)(Math.random()*100));
					String data1 = (String) exchanger.exchange(data);
					System.out.println(Thread.currentThread().getName() + "交易得到:"+ data1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
		});
		
		 executorSer.shutdown();
	}
}