Question

为什么不在Callable中设置中断位会导致表示Callable的Future在调用Future.get（）时抛出TimeoutException？

public class ExecutorServiceTest extends MockitoTestCase {
  private static CountDownLatch latch1 = new CountDownLatch(1);

  class TaskChecksForInterruptedExcAndDoesSetInterruptedBit implements Callable<String> {
    @Override
    public String call() {
      latch1.countDown();
      while (!Thread.currentThread().isInterrupted()) {
      }
      Thread.currentThread().interrupt();
      return "blah";
    }
  }

  void testInterrupt() throws Exception {
    ExecutorService pool = Executors.newFixedThreadPool(numThreads);
    Future<String> future = pool.submit(new TaskChecksForInterruptedExcAndDoesSetInterruptedBit());
    latch1.await(); // Don't interrupt the Callable until it actually starts processing
    pool.shutdownNow();
    try {
      future.get(100, TimeUnit.MILLISECONDS);
    } catch (final TimeoutException e) {
      // Why doesn't this get called!
      return;
    }
    fail();
  }
}

Answer 1

shutdownNow（）调用尝试中断所有正在运行的任务。在这种情况下，在繁忙的循环中检测到中断，因此代码继续，Callable返回＆＃34; blah＆＃34; （而不是例外）
根据规范，TimeoutException仅在线程等待完整的超时期限时抛出，但没有结果可用。中断不适合这种情况。
您对CountDownLatch的使用不正确。你递减了，但我没有看到对latch1.await（）

设置中断位不会使Future.get（）抛出TimeoutException

1 个答案: