如何知道闩锁是否完成了任务

Question

I have two threads with countDownLatch set to 1, so that, when the first threads finishes the second should starts. And what I want to do is, when the second finishes its task, I want to get the data computed from both threads to do some operations.

now my question is, is there any way to know if the CountDownLatch object finished its task?

Update

is it safe to use

while (latch.getcountDown()==0) {
 // do the calculations on the data processed by the two threads
}

Answer 1

Yes when your thread finishes and is capable of say accepting request or a particular task, it call countDown method on latch. And on the other hand in your main thread (or your co-ordinator thread), block on await method on latch.

Now whenever 'x' slave threads completes their task and calls countDown, master knows about the same and comes out of await and does further processing.

Answer 2

Have you tried 'join' for the threads. Instead of using a heavy latch join might do the trick.