<Swing Dev> [9] Review Request for 8130735: javax.swing.TimerQueue: timer fires late when another timer starts

[Alexander Scherbatiy]

   What about to add removed flat to DelayedTimer? Something like:
   TimerQueue.removeTimer(Timer timer){
     timer.lock();
     // ...
     timer.delayedTimer.removed = true;
     queue.remove(timer.delayedTimer);
     timer.delayedTimer = null;
     timer.unlock();
}

TimerQueue.run(){
     DelayedTimer delayedTimer = queue.take();
     delayedTimer.getTimer().lock();
     if(delayedTimer.removed){
         // skip it
     }
     // ...
     delayedTimer.getTimer().unlock();
}

  Thanks,
  Alexandr.


On 7/17/2015 12:28 AM, Sergey Bylokhov wrote:
> Hi, Semyon.
> I see that the chance to reproduce the problem is very very small, 
> because we should call addTimer, when we are at lines 171/172. So the 
> bug is about really small timings. So the related question: Is it 
> possible in the fixed version to call addTimer when we remove 
> DelayedTimer from the queue via queue.take(), but before we assign its 
> value to the runningTimer?
>
> On 14.07.15 12:51, Alexander Zvegintsev wrote:
>> still looks good to me.
>>
>> Thanks,
>>
>> Alexander.
>>
>> On 07/14/2015 12:41 PM, Semyon Sadetsky wrote:
>>> Hi Alexander,
>>>
>>> I added the double check 
>>> :http://cr.openjdk.java.net/~ssadetsky/8130735/webrev.01/
>>>
>>> --Semyon
>>>
>>> On 7/13/2015 1:24 PM, Alexander Zvegintsev wrote:
>>>> Hello Semyon,
>>>>
>>>> the fix looks good to me.
>>>>
>>>> P.S. Just a side note, as I can see we could possibly start two 
>>>> threads instead of one in startIfNeeded():
>>>>
>>>>   96     void startIfNeeded() {
>>>>   97         if (! running) {
>>>>   98             runningLock.lock();
>>>>   99             try {
>>>>  100                 final ThreadGroup threadGroup = 
>>>> AppContext.getAppContext().getThreadGroup();
>>>>  101 AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
>>>>  102                     String name = "TimerQueue";
>>>>  103                     Thread timerThread = new 
>>>> ManagedLocalsThread(threadGroup,
>>>>  104 this, name);
>>>>
>>>> !running check is missing after try. It is not the case with 
>>>> current code base, but it may be changed in future.
>>>>
>>>> Thanks,
>>>>
>>>> Alexander.
>>>>
>>>> On 07/09/2015 08:08 PM, Semyon Sadetsky wrote:
>>>>> Hello,
>>>>>
>>>>> Please review fix for JDK9:
>>>>>
>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8130735
>>>>> webrev: http://cr.openjdk.java.net/~ssadetsky/8130735/webrev.00/
>>>>>
>>>>> The root cause is the setting larger expiration time for the timer 
>>>>> which is already inserted into the delay queue. So all timers 
>>>>> behind the timer cannot be executed earlier than its expiration 
>>>>> time. This happens very rare only for repeated timers and only if 
>>>>> user uses the Swing timer API inaccurately (call start() without 
>>>>> stop()).
>>>>> The fix eliminates this possibility by introducing a check if the 
>>>>> timer was already restarted concurrently.
>>>>> It is difficult to write test because I could not reliably 
>>>>> reproduce the issue for a reasonable time.
>>>>>
>>>>> --Semyon
>>>>
>>>
>>
>
>
> -- 
> Best regards, Sergey.