Thank you for the double click pointers. These methods are useful bits of
knowledge and it is heartening that I am not the only one to experience
these occurrences. However, the primary question that I have is thread
safety. My user can press multiple keys simultaneously or nearly
simultaneously. Each key press performs a different function and calls the
update manager with code similar to this:
myCanvas.getUpdateManger().getUpdateRunnableQueue().invokeLater(new
Runnable() {
public void run()
{
performSVGUpdate1();
}
});
}
1. Are multiple occurrences of code execution like this thread safe?
2. Is this simply placing all of the Runnable objects in a queue for the
update manager to execute later?
3. Would it cause a problem if the update manager thread were running when
we attempt to add another Runnable object to the queue?
Threads can be a source of great frustration to debug and I would like to
get a better understanding of what is going on so I can prevent any
conflicts before they happen. When I write threads, I know exactly what is
occurring and can prepare for it. Here there are tools that are performing
many methods for me and I am uncertain as to what precautions I should take.
Any additional insight into the matter that I haven't mentioned regarding
threads would be appreciated too.
Sincerely,
Tim Apessos
-----Original Message-----
From: Tonny Kohar [mailto:[EMAIL PROTECTED]
Sent: Thursday, April 20, 2006 10:55 PM
To: [email protected]
Subject: Re: Update Manager thread safety question
Hi,
On Java Standard MouseEvent, you could detect it is either single click
or double click by using mouseEvent.getClickCount(). The threshold
between click is determined by the JVM, which hopefully follows the
platform it run (Win XP, linux, etc)
Regards
Tonny Kohar
--
Sketsa
SVG Graphics Editor
http://www.kiyut.com
On Thu, 2006-04-20 at 23:49 +0100, Lewis Keen wrote:
> Tim,
>
> During my final year project development (Poker game) I too noticed
> the problem with double clicking on an element. I used this method on
> my "click" event listeners:
>
> public boolean isSingleClick(Event evt)
> {
> MouseEvent me=(MouseEvent)evt;
> return me.getDetail()==1;
> }
>
> where the MouseEvent is a org.w3c.dom.events.MouseEvent and not a
> standard java.awt.event.MouseEvent. This seemed to fix most of the
> problems I was having, however this is still the odd occasion where it
> does a double-click (not sure if its me or this dodgy mouse). I
> consequently removed the flags that I was originally using and it
> seemed to work fine.
>
> As to the two key listeners, it may be useful to have a brief
> explanation of what the listeners do and if the affect each other in a
> major way. I would imagine that the problem is similar to the problem
> a double-click would have, and I did have some problems with the lock
> not occuring quickly enough when doing a double-click. Sorry if this
> is waffle, its a little hard to explain :/
>
> Hope this helps,
>
> Lewis
>
> On 4/20/06, Tim Apessos <[EMAIL PROTECTED]> wrote:
> >
> >
> >
> > I took all the useful advice given to me on my SVG Update problem and
fixed
> > the problem that I was having. Thank you. I am curious about one other
> > item.
> >
> >
> >
> > If I have two key listeners as in the example below and the user presses
the
> > keys nearly simultaneously, are there any thread safety issues that I
need
> > to worry about? As a precaution I've put flags in the listeners that I
have
> > written so far to prevent a double click while an update has not
occurred
> > but have not done so to prevent multiple keys from attempting to call
the
> > Update Manager at the same time. Is this an issue that I need to be
> > concerned with?
> >
> >
> >
> > Public class KeyListener1{
> >
> > .
> >
> > .
> >
> > .
> >
> > JSVGCanvas myCanvas;
> >
> > myCanvas.getUpdateManger().getUpdateRunnableQueue().invokeLater(new
> > Runnable() {
> > public void run()
> > {
> > performSVGUpdate1();
> > }
> > });
> > }
> >
> >
> >
> >
> >
> >
> > Public class KeyListener2{
> >
> > JSVGCanvas myCanvas;
> >
> > myCanvas.getUpdateManger().getUpdateRunnableQueue().invokeLater(new
> > Runnable() {
> > public void run()
> > {
> > performSVGUpdate2();
> > }
> > });
> >
> >
> > }
> >
> >
> >
> > Thanks,
> >
> > Tim
>
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