import java.util.concurrent.Semaphore;

/**

* 编写一个程序，开启三个线程，这三个线程的 ID 分别是 A、B 和 C，每个线程把自己的 ID 在屏幕上打印 10 遍，

* 要求输出结果必须按 ABC 的顺序显示，如 ABCABCABC... 依次递推

*

* 使用 Semaphore 实现

*/

public class AbcSemaphore {

public static void main(String[] args) {

Semaphore semaphoreA = new Semaphore(1);

Semaphore semaphoreB = new Semaphore(0);

Semaphore semaphoreC = new Semaphore(0);

new Thread(()->{

try {

while (true) {

semaphoreA.acquire();

System.out.print(Thread.currentThread().getName());

semaphoreB.release();

}

} catch (InterruptedException e) {

e.printStackTrace();

}

},"A").start();

new Thread(()->{

try {

while (true) {

semaphoreB.acquire();

System.out.print(Thread.currentThread().getName());

semaphoreC.release();

}

} catch (InterruptedException e) {

e.printStackTrace();

}

},"B").start();

new Thread(()->{

try {

while (true) {

semaphoreC.acquire();

System.out.println(Thread.currentThread().getName());

semaphoreA.release();

}

} catch (InterruptedException e) {

e.printStackTrace();

}

},"C").start();

}

}