AQS框架实现类学习

CountDownLatch：允许一个或者多个线程等待其他线程完成操作

/**
 * 

 * 
 * @author jinxindong 2016年11月1日 上午9:33:46
 * @version V1.0
 */
public class CountDownLatchDemo {
	
	final static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	
	public static void main(String[] args) throws InterruptedException {
		CountDownLatch countDownLatch = new CountDownLatch(2);//计数数量
		Worker worker1 = new Worker("zhang san", 5000, countDownLatch);
		Worker worker2 = new Worker("li si", 8000, countDownLatch);
		worker1.start();//
		worker2.start();//
		countDownLatch.await();//如果计数到达零，则释放所有等待的线程。
		System.out.println("all work done at " + sdf.format(new Date()));
	}
	static class Worker extends Thread {	
		String workerName;
		int workTime;
		CountDownLatch countDownLatch;
		
		public Worker(String workerName, int workTime, CountDownLatch countDownLatch) {
			this.countDownLatch = countDownLatch;
			this.workerName = workerName;
			this.workTime = workTime;
		}		
		public void run() {
			try {
				System.out.println("Worker " + workerName + " do work begin at " + sdf.format(new Date()));
				Thread.sleep(workTime);// 工作了
				System.out.println("Worker " + workerName + " do work complete at " + sdf.format(new Date()));
			} catch (InterruptedException e) {
				e.printStackTrace();
			} finally {
				countDownLatch.countDown();//递减锁存器的计数。
			}	
		}
		 
	}
}

cyclicBarrier 同步屏障：
拦截到所有后，释放，所有被拦截的线程才会继续进行

cyclicBarrier和CountDownLatch的区别：
countDownLatch只能用一次，cyclicBarrier的计数器可以使用reset（）方法重置。

Semaphore：同事允许几个线程并发操作共享资源  方法： acquire（） 和release（）

/**
 * 

 * @author jinxindong 2016年10月31日 下午4:42:07
 * @version V1.0 
 */
//创建一个会实现print queue的类名为PrintQueue
public class PrintQueue {
	
	private final Semaphore semaphore;//声明对象为一个semaphore 信号量
	public PrintQueue(){
		semaphore = new Semaphore(2);
	}
	
	//实现打印功能  模拟打印文档
	public void printJob(Object document){
		try {
	        semaphore.acquire();
	        long duration = (long)(Math.random()*10);
	        System.out.printf("%s: PrintQueue: Printing a Job during %d seconds\n",Thread.currentThread().getName(),duration);
            Thread.sleep(duration);
            
		} catch (Exception e) {
	        // TODO: handle exception
			 e.printStackTrace();
        }finally{
        	semaphore.release();
        }
	}
		
}

Exchanger：两个线程间，的数据交换。如果多余两个取前两个。执行exchange后，返回值是另一个线程的结果。

/**
 * 

 * @author jinxindong 2016年11月1日 上午10:29:45
 * @version V1.0 
 */
public class ExchangerTest {
	
	private static final Exchanger exc = new Exchanger();
	private static ExecutorService executorService =  Executors.newFixedThreadPool(2);
	
	/**
	 * @author jinxindong 2016年11月1日 上午10:29:45
	 * @param args
	 */
	public static void main(String[] args) {
		//执行线程A
		executorService.execute(new Runnable() {			
			@Override
			public void run() {
				try {
	                String A = "银行流水A";
	                String b = exc.exchange(A); 
	                System.out.println(" b= "+b);
                } catch (Exception e) {
	                e.printStackTrace();
                }				
			}
		});
		
		//执行线程B
		executorService.execute(new Runnable() {			
			@Override
			public void run() {	
				try {
					String B = "银行流水B";
	               String a = exc.exchange(B);
	               System.out.println(" a= "+a);
                } catch (InterruptedException e) {
	                e.printStackTrace();
                }
			}
		});
		
		executorService.shutdown();
	}
	
}

Phaser：

可以代替countDownLatch和CyclicBarrier

1  Phaser pha = new Phaser（2）；//countDownLatch（2）

    pha.arrive() // latch.countDown() 减1

    pha.awaitAdvance // latch.await()

2   Phaser pha = new Phaser（2）；

     pha.arriveAndAwaitAdvance（） // cyc.await（）