java多線程 核心類庫與方法 CountDownLatch

利用CountDownLatch模擬跑步比賽.

要點

1.await().//當計數器不爲0的時候,阻塞線程。

2.countDown().//技術器減1.

//測試創建啓動類

public class CountDownLatchMatch {
	public static void main(String[] args) throws InterruptedException {
		
		CountDownLatch       coming  = new CountDownLatch(10);
		CountDownLatch      waiting  = new CountDownLatch(1);
		CountDownLatch   waitToRace  = new CountDownLatch(10);
		CountDownLatch    startRace  = new CountDownLatch(1);
		CountDownLatch      endRace  = new CountDownLatch(10);
		
		MyService myService = new MyService(coming, waiting,waitToRace, startRace, endRace);
		Mythread []mythread = new Mythread[10];
		
		for(int i=0;i<10;i++){
			mythread[i] = new Mythread(myService);
			mythread[i].setName(i+1+"號運動員");
			mythread[i].start();
		}
		
		System.out.println("裁判正在等待運動員到達.");
		coming.await();
		
	//	Thread.sleep(2000);
		System.out.println("****運動員全部到達起始點******");
		waiting.countDown();
		
		waitToRace.await();
		System.out.println("****運動員全部到已經準備好*****");
		
		startRace.countDown();
		endRace.await();
		
		System.out.println("****比賽結束！****");
		
		
	}
}
//創建自定義線程


public class Mythread extends Thread{
	
	private MyService myService;
	
	public Mythread(MyService myService) {
		this.myService = myService;
	}
	
	
	@Override
	public void run() {
		try {
			myService.testMethod();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}// 創建service 

public class MyService {
	
	CountDownLatch coming;
	CountDownLatch waiting;
	CountDownLatch waitToRace;
	CountDownLatch startRace;
	CountDownLatch endRace;
	
	
	public MyService(CountDownLatch coming,CountDownLatch waiting,CountDownLatch waitToRace,CountDownLatch startRace,CountDownLatch endRace) 
	{
		   this.coming     = coming;
		   this.waiting	   = waiting;
		   this.waitToRace = waitToRace;
		   this.startRace  = startRace;
		   this.endRace    = endRace;
	}
	
	public void testMethod() throws InterruptedException{
		
		System.out.println("運動員  開始往起跑點方向走.");
		Thread.sleep((int)Math.random()*10000 );
		System.out.println("運動員  "+Thread.currentThread().getName()+"到達起始點.");
		coming.countDown();
		waiting.await();
		System.out.println("裁判宣佈準備跑了.");
		System.out.println(Thread.currentThread().getName()+"已經準備好");
		waitToRace.countDown();
		startRace.await();
		System.out.println(Thread.currentThread().getName()+"已經跑完.計時不詳");
		endRace.countDown();
	}
	
}