<AWT Dev> [11][JDK-8152974] AWT hang occurs when sequenced events

[Sergey Bylokhov]

On 14/03/2018 07:53, Krishna Addepalli wrote:
> As per our discussion, I have modified the fix to process only SequencedEvents and ignore others. I have also modified the test case to include some dummy events between two SequencedEvents, and it works.

Looks fine.

> However, could you point me to a doc/spec which says that all the SequencedEvents have to be processed together, even if other events in the queue have arrived before?

This class is not public so it behavior is not completely specified. But 
even this javadoc specified that "If this method is invoked before all 
previous nested events have been dispatched, then this method blocks 
until such a point is reached." So yes SequencedEvents should be 
processed together according their order. it does not specify should we 
dispatch other events in between. But if we will dispatch other event 
then we will introduce "out of order dispatching", when some event which 
was posted after SequencedEvent will be dispatched first. So the 
question is why we need this "sort of out of order execution".

> 
> Thanks,
> Krishna
> 
> -----Original Message-----
> From: Krishna Addepalli
> Sent: Saturday, February 17, 2018 7:57 AM
> To: Sergey Bylokhov <sergey.bylokhov at oracle.com>; awt-dev at openjdk.java.net; Semyon Sadetsky <semyon.sadetsky at oracle.com>
> Subject: RE: <AWT Dev> [11][JDK-8152974] AWT hang occurs when sequenced events
> 
> Hi Sergey,
> 
> The event is present, but with the id "java.awt.event.FocusEvent.FOCUS_LAST+1", whereas when it is pumping the events, it is looking for "java.awt.event.FocusEvent.FOCUS_LAST+2", which is not in the queue.
> 
> Thanks,
> Krishna
> 
> -----Original Message-----
> From: Sergey Bylokhov
> Sent: Saturday, February 17, 2018 1:49 AM
> To: Krishna Addepalli <krishna.addepalli at oracle.com>; awt-dev at openjdk.java.net; Semyon Sadetsky <semyon.sadetsky at oracle.com>
> Subject: Re: <AWT Dev> [11][JDK-8152974] AWT hang occurs when sequenced events
> 
> Hi, Krishna.
> On 16/02/2018 00:42, Krishna Addepalli wrote:
>> The SentEvent.ID value is "java.awt.event.FocusEvent.FOCUS_LAST+2", and when in the function pumpOneEventForFilters, it tries to call EventQueue.getNextEvent(id), it looks for SentEvent.ID, which is not present, and then the queue blocks in the hope that someone will post that event. This is what is leading to the hang.
> 
> But both events are posted by the test, why the second event is not present in the queue?
> 
> 


-- 
Best regards, Sergey.