Prevent AWT Event Queue from overloading

Question

I have coded a Swing GUI, which uses KeyAccelerators on JMenuItems. Pressing the keys that trigger the Accelerator for a longer time causes the EventQueue to stack commands and blocking the GUI. I want the AWT Event Queue not to have more than one (or two) KeyEvents with Control Modifier in it. I tried this:

         AWTEvent awtevent = Toolkit.getDefaultToolkit()
                        .getSystemEventQueue().peekEvent();
                if (awtevent != null) {
                    String paramString = awtevent.paramString();
                    if ((paramString.indexOf("modifiers=Ctrl") != -1 && ((KeyEvent) event)
                            .isControlDown())) {
                        ((KeyEvent) event).consume();
                    } else if (paramString.indexOf("modifiers=Ctrl") != -1
                            && (paramString.indexOf("keyChar=Undefined") != -1)) {
                        ((KeyEvent) event).consume();

                    }
                }

But its very unreliable as it sometimes consumes an Event that shouldnt be consumed.

score 2 · Accepted Answer · answered Oct 10 '14 at 20:18

You cannot reliably do this from the outside. It is not thread-safe to manipulate the event queue from outside the event-dispatch thread, and you cannot execute a task on the event dispatch thread that that mucks with events posted prior to that task itself being processed. You could maybe push a cleanup task onto the queue every second or two that would handle yet-to-be-processed events, but ... just don't.

If you want to filter AWT / Swing events then you need to install your own event queue, which is easier than it may sound. You may find this article to be instructive.

Prevent AWT Event Queue from overloading

1 Answers1