From: "Brad Urani" <[EMAIL PROTECTED]>
Sent: Thursday, May 23, 2002 7:36 PM
> I have a program that calls Behavior.postId() in a
> thread with waits like so.
>
> for(c=0; c<100; c++)
> {
> behavior.postId(1);
> Thread.sleep(20);
> wait();
> }
>
> The behavior class calls notify() when it finishes so
> the loop can continue, But I've noticed that if I set
> the sleep too low the 3D thread will miss the behavior
> post and get stuck at the wait() freezing my program.
> Does anyone know how to guard against missed posts
> like this?
I've been holding off a bit on this, hoping for an answer from someone who
knew something about threads. I haven't figured my way around Java threads,
but I have learned to avoid tricky wait/notify structures like the plague,
and, most especially, I wouldn't let them near J3D.
I can't read your exact problem here, but I can say that you're working in a
frequency range that is very close to the one used by the J3D Behavior
scheduler to poll its wakeup queue so I think you can expect trouble (the
way this works is undocumented so I'm just guessing based on testing and
observation, and in fact, I'm pretty sure it changed from 1.2 to 1.3)
Further, I'm pretty sure that when a Behavior wakes up, it flushes its
queue, so you're responsible for dissecting the wakeup condition and feeding
its components to the proper response methods. At least this is the only
way I've gotten my Behaviors to work reliably. YMMV. So if your postId was
stacked up behind another wakeup and you didn't handle the sequence
properly, you may miss it, and your program would hang in the wait().
If you're trying to do something about timing Behaviors or sequencing
sampling, then I think you'd be much better off moving everything onto a
Behavior.
Not much, but I hope this helps.
Fred Klingener
Brock Engineering
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