Sleep and check until condition is true

Question

Is there a library in Java that does the following? A thread should repeatedly sleep for x milliseconds until a condition becomes true or the max t

Answer 1

EDIT

Most answers focus on the low level API with waits and notifies or Conditions (which work more or less the same way): it is difficult to get right when you are not used to it. Proof: 2 of these answers don't use wait correctly.
java.util.concurrent offers you a high level API where all those intricacies have been hidden.

IMHO, there is no point using a wait/notify pattern when there is a built-in class in the concurrent package that achieves the same.

---

A CountDownLatch with an initial count of 1 does exactly that:

• When the condition becomes true, call latch.countdown();
• in your waiting thread, use : boolean ok = latch.await(1, TimeUnit.SECONDS);

Contrived example:

final CountDownLatch done = new CountDownLatch(1);

new Thread(new Runnable() {

    @Override
    public void run() {
        longProcessing();
        done.countDown();
    }
}).start();

//in your waiting thread:
boolean processingCompleteWithin1Second = done.await(1, TimeUnit.SECONDS);

Note: CountDownLatches are thread safe.