/**
* Fetches and possibly removes the next event from the internal queues. This method returns
* immediately. When all queues are empty, this returns <code>null</code>:
*
* @param remove <true> when the event should be removed from the queue, <code>false</code>
* otherwise
* @return the next event or <code>null</code> when all internal queues are empty
*/
private AWTEvent getNextEventImpl(boolean remove) {
AWTEvent next = null;
for (int i = 0; i < queues.length && next == null; i++) {
Queue q = queues[i];
if (q.queueHead != null) {
// Got an event, remove it.
next = q.queueHead;
if (remove) {
// Unlink event from the queue.
q.queueHead = next.queueNext;
if (q.queueHead == null) q.queueTail = null;
next.queueNext = null;
}
}
}
return next;
}
/**
* Actually performs the event posting. This is needed because the RI doesn't use the public
* postEvent() method when transferring events between event queues in push() and pop().
*
* @param evt the event to post
* @param priority the priority of the event
*/
private final void postEventImpl(AWTEvent evt, int priority) {
if (evt == null) throw new NullPointerException();
if (next != null) {
next.postEvent(evt);
return;
}
Object source = evt.getSource();
Queue q = queues[priority];
if (source instanceof Component) {
// For PaintEvents, ask the ComponentPeer to coalesce the event
// when the component is heavyweight.
Component comp = (Component) source;
ComponentPeer peer = comp.peer;
if (peer != null && evt instanceof PaintEvent && !(peer instanceof LightweightPeer))
peer.coalescePaintEvent((PaintEvent) evt);
// Check for any events already on the queue with the same source
// and ID.
AWTEvent previous = null;
for (AWTEvent qevt = q.queueHead; qevt != null; qevt = qevt.queueNext) {
Object src = qevt.getSource();
if (qevt.id == evt.id && src == comp) {
// If there are, call coalesceEvents on the source component
// to see if they can be combined.
Component srccmp = (Component) src;
AWTEvent coalescedEvt = srccmp.coalesceEvents(qevt, evt);
if (coalescedEvt != null) {
// Yes. Replace the existing event with the combined event.
if (qevt != coalescedEvt) {
if (previous != null) {
assert previous.queueNext == qevt;
previous.queueNext = coalescedEvt;
} else {
assert q.queueHead == qevt;
q.queueHead = coalescedEvt;
}
coalescedEvt.queueNext = qevt.queueNext;
if (q.queueTail == qevt) q.queueTail = coalescedEvt;
qevt.queueNext = null;
}
return;
}
}
previous = qevt;
}
}
if (q.queueHead == null) {
// We have an empty queue. Set this event both as head and as tail.
q.queueHead = evt;
q.queueTail = evt;
} else {
// Note: queueTail should not be null here.
q.queueTail.queueNext = evt;
q.queueTail = evt;
}
if (dispatchThread == null || !dispatchThread.isAlive()) {
dispatchThread = new EventDispatchThread(this);
dispatchThread.start();
}
notify();
}
