java中的CyclicBarrier的问题
古月椒 2016-05-10 09:14:48 package cn.itcast;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class CyclicBarrierTest {
public static void main(String[] args) {
ExecutorService service = Executors.newCachedThreadPool();
final CyclicBarrier cb = new CyclicBarrier(3);
for (int i = 0; i < 3; i++) {
Runnable runnable = new Runnable() {
public void run() {
try {
Thread.sleep((long) Math.random() * 10000);
System.out.println("线程" + Thread.currentThread().getName() +
"即将到达集合地点1,当前已有"+ (cb.getNumberWaiting() + 1) + "个已经到达,"
+ (cb.getNumberWaiting() == 2 ? "都到齐了,继续走啊" : "继续等待"));
cb.await();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (BrokenBarrierException e) {
e.printStackTrace();
}
}
};
service.execute(runnable);
}
service.shutdown();
}
}
上述代码执行过程中,getNumberWaiting()方法不能正确打印出正在等待的线程数。。很奇怪,这里也不需要什么同步的问题吧,运行了好多次。。还求大神赐教。。