Re: wait finishes early?

"Mike Schilling" <>
Tue, 8 Dec 2009 20:54:38 -0800
John B. Matthews wrote:

In article
mikew01 <> wrote:

I am trying to write a method that detects when a thread has timed
out waiting for a resource, for brevity I have included the
parts below in the lock method. I am finding that when I specify a
value of around 6000ms and above the period is calculated lower
the timeout which results in the code thinking that the thread has
not timed out waiting but has simply been released from a notify.
It appears that either wait( timeout ) is releasing early or I am
using the correct method for gauging the time to obtain period.
  synchronized ( requester )
   requester.wait( timeout );


"Always invoke wait inside a loop that tests for the condition being
waited for."


This looks to me like the correct logic, encapsulated reasonably well:

public class EventUtils
    public static void waitforEvent(
            long maxDelay, Object lock, EventChecker checker)
                throws InterruptedException
            long start = System.currentTimeMillis();
            long toWait = maxDelay;
            while (true)
                if (checker.isDone())
                if (maxDelay > 0)
                    long elapsed = System.currentTimeMillis() - start;
                    if (elapsed >= maxDelay)
                    toWait = maxDelay - elapsed;

    public interface EventChecker
        boolean isDone();

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