1 /*
2 * Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.awt;
27
28 import java.awt.event.*;
29
30 import java.awt.peer.ComponentPeer;
31
32 import java.lang.ref.WeakReference;
33 import java.lang.reflect.InvocationTargetException;
34
35 import java.security.AccessController;
36 import java.security.PrivilegedAction;
37
38 import java.util.EmptyStackException;
39
40 import sun.awt.*;
41 import sun.awt.dnd.SunDropTargetEvent;
42 import sun.util.logging.PlatformLogger;
43
44 import java.util.concurrent.locks.Condition;
45 import java.util.concurrent.locks.Lock;
46 import java.util.concurrent.atomic.AtomicInteger;
47
48 import java.security.AccessControlContext;
49
50 import jdk.internal.misc.SharedSecrets;
51 import jdk.internal.misc.JavaSecurityAccess;
52
53 /**
54 * {@code EventQueue} is a platform-independent class
55 * that queues events, both from the underlying peer classes
56 * and from trusted application classes.
57 * <p>
58 * It encapsulates asynchronous event dispatch machinery which
59 * extracts events from the queue and dispatches them by calling
60 * {@link #dispatchEvent(AWTEvent) dispatchEvent(AWTEvent)} method
61 * on this {@code EventQueue} with the event to be dispatched
62 * as an argument. The particular behavior of this machinery is
63 * implementation-dependent. The only requirements are that events
64 * which were actually enqueued to this queue (note that events
65 * being posted to the {@code EventQueue} can be coalesced)
66 * are dispatched:
67 * <dl>
68 * <dt> Sequentially.
69 * <dd> That is, it is not permitted that several events from
70 * this queue are dispatched simultaneously.
71 * <dt> In the same order as they are enqueued.
72 * <dd> That is, if {@code AWTEvent} A is enqueued
73 * to the {@code EventQueue} before
74 * {@code AWTEvent} B then event B will not be
75 * dispatched before event A.
76 * </dl>
77 * <p>
78 * Some browsers partition applets in different code bases into
79 * separate contexts, and establish walls between these contexts.
80 * In such a scenario, there will be one {@code EventQueue}
81 * per context. Other browsers place all applets into the same
82 * context, implying that there will be only a single, global
83 * {@code EventQueue} for all applets. This behavior is
84 * implementation-dependent. Consult your browser's documentation
85 * for more information.
86 * <p>
87 * For information on the threading issues of the event dispatch
88 * machinery, see <a href="doc-files/AWTThreadIssues.html#Autoshutdown"
89 * >AWT Threading Issues</a>.
90 *
91 * @author Thomas Ball
92 * @author Fred Ecks
93 * @author David Mendenhall
94 *
95 * @since 1.1
96 */
97 public class EventQueue {
98 private static final AtomicInteger threadInitNumber = new AtomicInteger(0);
99
100 private static final int LOW_PRIORITY = 0;
101 private static final int NORM_PRIORITY = 1;
102 private static final int HIGH_PRIORITY = 2;
103 private static final int ULTIMATE_PRIORITY = 3;
104
105 private static final int NUM_PRIORITIES = ULTIMATE_PRIORITY + 1;
106
107 /*
108 * We maintain one Queue for each priority that the EventQueue supports.
109 * That is, the EventQueue object is actually implemented as
110 * NUM_PRIORITIES queues and all Events on a particular internal Queue
111 * have identical priority. Events are pulled off the EventQueue starting
112 * with the Queue of highest priority. We progress in decreasing order
113 * across all Queues.
114 */
115 private Queue[] queues = new Queue[NUM_PRIORITIES];
116
117 /*
118 * The next EventQueue on the stack, or null if this EventQueue is
119 * on the top of the stack. If nextQueue is non-null, requests to post
120 * an event are forwarded to nextQueue.
121 */
122 private EventQueue nextQueue;
123
124 /*
125 * The previous EventQueue on the stack, or null if this is the
126 * "base" EventQueue.
127 */
128 private EventQueue previousQueue;
129
130 /*
131 * A single lock to synchronize the push()/pop() and related operations with
132 * all the EventQueues from the AppContext. Synchronization on any particular
133 * event queue(s) is not enough: we should lock the whole stack.
134 */
135 private final Lock pushPopLock;
136 private final Condition pushPopCond;
137
138 /*
139 * Dummy runnable to wake up EDT from getNextEvent() after
140 push/pop is performed
141 */
142 private static final Runnable dummyRunnable = new Runnable() {
143 public void run() {
144 }
145 };
146
147 private EventDispatchThread dispatchThread;
148
149 private final ThreadGroup threadGroup =
150 Thread.currentThread().getThreadGroup();
151 private final ClassLoader classLoader =
152 Thread.currentThread().getContextClassLoader();
153
154 /*
155 * The time stamp of the last dispatched InputEvent or ActionEvent.
156 */
157 private long mostRecentEventTime = System.currentTimeMillis();
158
159 /*
160 * The time stamp of the last KeyEvent .
161 */
162 private long mostRecentKeyEventTime = System.currentTimeMillis();
163
164 /**
165 * The modifiers field of the current event, if the current event is an
166 * InputEvent or ActionEvent.
167 */
168 private WeakReference<AWTEvent> currentEvent;
169
170 /*
171 * Non-zero if a thread is waiting in getNextEvent(int) for an event of
172 * a particular ID to be posted to the queue.
173 */
174 private volatile int waitForID;
175
176 /*
177 * AppContext corresponding to the queue.
178 */
179 private final AppContext appContext;
180
181 private final String name = "AWT-EventQueue-" + threadInitNumber.getAndIncrement();
182
183 private FwDispatcher fwDispatcher;
184
185 private static volatile PlatformLogger eventLog;
186
187 private static final PlatformLogger getEventLog() {
188 if(eventLog == null) {
189 eventLog = PlatformLogger.getLogger("java.awt.event.EventQueue");
190 }
191 return eventLog;
192 }
193
194 static {
195 AWTAccessor.setEventQueueAccessor(
196 new AWTAccessor.EventQueueAccessor() {
197 public Thread getDispatchThread(EventQueue eventQueue) {
198 return eventQueue.getDispatchThread();
199 }
200 public boolean isDispatchThreadImpl(EventQueue eventQueue) {
201 return eventQueue.isDispatchThreadImpl();
202 }
203 public void removeSourceEvents(EventQueue eventQueue,
204 Object source,
205 boolean removeAllEvents)
206 {
207 eventQueue.removeSourceEvents(source, removeAllEvents);
208 }
209 public boolean noEvents(EventQueue eventQueue) {
210 return eventQueue.noEvents();
211 }
212 public void wakeup(EventQueue eventQueue, boolean isShutdown) {
213 eventQueue.wakeup(isShutdown);
214 }
215 public void invokeAndWait(Object source, Runnable r)
216 throws InterruptedException, InvocationTargetException
217 {
218 EventQueue.invokeAndWait(source, r);
219 }
220 public void setFwDispatcher(EventQueue eventQueue,
221 FwDispatcher dispatcher) {
222 eventQueue.setFwDispatcher(dispatcher);
223 }
224
225 @Override
226 public long getMostRecentEventTime(EventQueue eventQueue) {
227 return eventQueue.getMostRecentEventTimeImpl();
228 }
229 });
230 }
231
232 /**
233 * Initializes a new instance of {@code EventQueue}.
234 */
235 public EventQueue() {
236 for (int i = 0; i < NUM_PRIORITIES; i++) {
237 queues[i] = new Queue();
238 }
239 /*
240 * NOTE: if you ever have to start the associated event dispatch
241 * thread at this point, be aware of the following problem:
242 * If this EventQueue instance is created in
243 * SunToolkit.createNewAppContext() the started dispatch thread
244 * may call AppContext.getAppContext() before createNewAppContext()
245 * completes thus causing mess in thread group to appcontext mapping.
246 */
247
248 appContext = AppContext.getAppContext();
249 pushPopLock = (Lock)appContext.get(AppContext.EVENT_QUEUE_LOCK_KEY);
250 pushPopCond = (Condition)appContext.get(AppContext.EVENT_QUEUE_COND_KEY);
251 }
252
253 /**
254 * Posts a 1.1-style event to the {@code EventQueue}.
255 * If there is an existing event on the queue with the same ID
256 * and event source, the source {@code Component}'s
257 * {@code coalesceEvents} method will be called.
258 *
259 * @param theEvent an instance of {@code java.awt.AWTEvent},
260 * or a subclass of it
261 * @throws NullPointerException if {@code theEvent} is {@code null}
262 */
263 public void postEvent(AWTEvent theEvent) {
264 SunToolkit.flushPendingEvents(appContext);
265 postEventPrivate(theEvent);
266 }
267
268 /**
269 * Posts a 1.1-style event to the {@code EventQueue}.
270 * If there is an existing event on the queue with the same ID
271 * and event source, the source {@code Component}'s
272 * {@code coalesceEvents} method will be called.
273 *
274 * @param theEvent an instance of {@code java.awt.AWTEvent},
275 * or a subclass of it
276 */
277 private final void postEventPrivate(AWTEvent theEvent) {
278 theEvent.isPosted = true;
279 pushPopLock.lock();
280 try {
281 if (nextQueue != null) {
282 // Forward the event to the top of EventQueue stack
283 nextQueue.postEventPrivate(theEvent);
284 return;
285 }
286 if (dispatchThread == null) {
287 if (theEvent.getSource() == AWTAutoShutdown.getInstance()) {
288 return;
289 } else {
290 initDispatchThread();
291 }
292 }
293 postEvent(theEvent, getPriority(theEvent));
294 } finally {
295 pushPopLock.unlock();
296 }
297 }
298
299 private static int getPriority(AWTEvent theEvent) {
300 if (theEvent instanceof PeerEvent) {
301 PeerEvent peerEvent = (PeerEvent)theEvent;
302 if ((peerEvent.getFlags() & PeerEvent.ULTIMATE_PRIORITY_EVENT) != 0) {
303 return ULTIMATE_PRIORITY;
304 }
305 if ((peerEvent.getFlags() & PeerEvent.PRIORITY_EVENT) != 0) {
306 return HIGH_PRIORITY;
307 }
308 if ((peerEvent.getFlags() & PeerEvent.LOW_PRIORITY_EVENT) != 0) {
309 return LOW_PRIORITY;
310 }
311 }
312 int id = theEvent.getID();
313 if ((id >= PaintEvent.PAINT_FIRST) && (id <= PaintEvent.PAINT_LAST)) {
314 return LOW_PRIORITY;
315 }
316 return NORM_PRIORITY;
317 }
318
319 /**
320 * Posts the event to the internal Queue of specified priority,
321 * coalescing as appropriate.
322 *
323 * @param theEvent an instance of {@code java.awt.AWTEvent},
324 * or a subclass of it
325 * @param priority the desired priority of the event
326 */
327 private void postEvent(AWTEvent theEvent, int priority) {
328 if (coalesceEvent(theEvent, priority)) {
329 return;
330 }
331
332 EventQueueItem newItem = new EventQueueItem(theEvent);
333
334 cacheEQItem(newItem);
335
336 boolean notifyID = (theEvent.getID() == this.waitForID);
337
338 if (queues[priority].head == null) {
339 boolean shouldNotify = noEvents();
340 queues[priority].head = queues[priority].tail = newItem;
341
342 if (shouldNotify) {
343 if (theEvent.getSource() != AWTAutoShutdown.getInstance()) {
344 AWTAutoShutdown.getInstance().notifyThreadBusy(dispatchThread);
345 }
346 pushPopCond.signalAll();
347 } else if (notifyID) {
348 pushPopCond.signalAll();
349 }
350 } else {
351 // The event was not coalesced or has non-Component source.
352 // Insert it at the end of the appropriate Queue.
353 queues[priority].tail.next = newItem;
354 queues[priority].tail = newItem;
355 if (notifyID) {
356 pushPopCond.signalAll();
357 }
358 }
359 }
360
361 private boolean coalescePaintEvent(PaintEvent e) {
362 ComponentPeer sourcePeer = ((Component)e.getSource()).peer;
363 if (sourcePeer != null) {
364 sourcePeer.coalescePaintEvent(e);
365 }
366 EventQueueItem[] cache = ((Component)e.getSource()).eventCache;
367 if (cache == null) {
368 return false;
369 }
370 int index = eventToCacheIndex(e);
371
372 if (index != -1 && cache[index] != null) {
373 PaintEvent merged = mergePaintEvents(e, (PaintEvent)cache[index].event);
374 if (merged != null) {
375 cache[index].event = merged;
376 return true;
377 }
378 }
379 return false;
380 }
381
382 private PaintEvent mergePaintEvents(PaintEvent a, PaintEvent b) {
383 Rectangle aRect = a.getUpdateRect();
384 Rectangle bRect = b.getUpdateRect();
385 if (bRect.contains(aRect)) {
386 return b;
387 }
388 if (aRect.contains(bRect)) {
389 return a;
390 }
391 return null;
392 }
393
394 private boolean coalesceMouseEvent(MouseEvent e) {
395 EventQueueItem[] cache = ((Component)e.getSource()).eventCache;
396 if (cache == null) {
397 return false;
398 }
399 int index = eventToCacheIndex(e);
400 if (index != -1 && cache[index] != null) {
401 cache[index].event = e;
402 return true;
403 }
404 return false;
405 }
406
407 private boolean coalescePeerEvent(PeerEvent e) {
408 EventQueueItem[] cache = ((Component)e.getSource()).eventCache;
409 if (cache == null) {
410 return false;
411 }
412 int index = eventToCacheIndex(e);
413 if (index != -1 && cache[index] != null) {
414 e = e.coalesceEvents((PeerEvent)cache[index].event);
415 if (e != null) {
416 cache[index].event = e;
417 return true;
418 } else {
419 cache[index] = null;
420 }
421 }
422 return false;
423 }
424
425 /*
426 * Should avoid of calling this method by any means
427 * as it's working time is dependent on EQ length.
428 * In the worst case this method alone can slow down the entire application
429 * 10 times by stalling the Event processing.
430 * Only here by backward compatibility reasons.
431 */
432 private boolean coalesceOtherEvent(AWTEvent e, int priority) {
433 int id = e.getID();
434 Component source = (Component)e.getSource();
435 for (EventQueueItem entry = queues[priority].head;
436 entry != null; entry = entry.next)
437 {
438 // Give Component.coalesceEvents a chance
439 if (entry.event.getSource() == source && entry.event.getID() == id) {
440 AWTEvent coalescedEvent = source.coalesceEvents(
441 entry.event, e);
442 if (coalescedEvent != null) {
443 entry.event = coalescedEvent;
444 return true;
445 }
446 }
447 }
448 return false;
449 }
450
451 private boolean coalesceEvent(AWTEvent e, int priority) {
452 if (!(e.getSource() instanceof Component)) {
453 return false;
454 }
455 if (e instanceof PeerEvent) {
456 return coalescePeerEvent((PeerEvent)e);
457 }
458 // The worst case
459 if (((Component)e.getSource()).isCoalescingEnabled()
460 && coalesceOtherEvent(e, priority))
461 {
462 return true;
463 }
464 if (e instanceof PaintEvent) {
465 return coalescePaintEvent((PaintEvent)e);
466 }
467 if (e instanceof MouseEvent) {
468 return coalesceMouseEvent((MouseEvent)e);
469 }
470 return false;
471 }
472
473 private void cacheEQItem(EventQueueItem entry) {
474 int index = eventToCacheIndex(entry.event);
475 if (index != -1 && entry.event.getSource() instanceof Component) {
476 Component source = (Component)entry.event.getSource();
477 if (source.eventCache == null) {
478 source.eventCache = new EventQueueItem[CACHE_LENGTH];
479 }
480 source.eventCache[index] = entry;
481 }
482 }
483
484 private void uncacheEQItem(EventQueueItem entry) {
485 int index = eventToCacheIndex(entry.event);
486 if (index != -1 && entry.event.getSource() instanceof Component) {
487 Component source = (Component)entry.event.getSource();
488 if (source.eventCache == null) {
489 return;
490 }
491 source.eventCache[index] = null;
492 }
493 }
494
495 private static final int PAINT = 0;
496 private static final int UPDATE = 1;
497 private static final int MOVE = 2;
498 private static final int DRAG = 3;
499 private static final int PEER = 4;
500 private static final int CACHE_LENGTH = 5;
501
502 private static int eventToCacheIndex(AWTEvent e) {
503 switch(e.getID()) {
504 case PaintEvent.PAINT:
505 return PAINT;
506 case PaintEvent.UPDATE:
507 return UPDATE;
508 case MouseEvent.MOUSE_MOVED:
509 return MOVE;
510 case MouseEvent.MOUSE_DRAGGED:
511 // Return -1 for SunDropTargetEvent since they are usually synchronous
512 // and we don't want to skip them by coalescing with MouseEvent or other drag events
513 return e instanceof SunDropTargetEvent ? -1 : DRAG;
514 default:
515 return e instanceof PeerEvent ? PEER : -1;
516 }
517 }
518
519 /**
520 * Returns whether an event is pending on any of the separate
521 * Queues.
522 * @return whether an event is pending on any of the separate Queues
523 */
524 private boolean noEvents() {
525 for (int i = 0; i < NUM_PRIORITIES; i++) {
526 if (queues[i].head != null) {
527 return false;
528 }
529 }
530
531 return true;
532 }
533
534 /**
535 * Removes an event from the {@code EventQueue} and
536 * returns it. This method will block until an event has
537 * been posted by another thread.
538 * @return the next {@code AWTEvent}
539 * @exception InterruptedException
540 * if any thread has interrupted this thread
541 */
542 public AWTEvent getNextEvent() throws InterruptedException {
543 do {
544 /*
545 * SunToolkit.flushPendingEvents must be called outside
546 * of the synchronized block to avoid deadlock when
547 * event queues are nested with push()/pop().
548 */
549 SunToolkit.flushPendingEvents(appContext);
550 pushPopLock.lock();
551 try {
552 AWTEvent event = getNextEventPrivate();
553 if (event != null) {
554 return event;
555 }
556 AWTAutoShutdown.getInstance().notifyThreadFree(dispatchThread);
557 pushPopCond.await();
558 } finally {
559 pushPopLock.unlock();
560 }
561 } while(true);
562 }
563
564 /*
565 * Must be called under the lock. Doesn't call flushPendingEvents()
566 */
567 AWTEvent getNextEventPrivate() throws InterruptedException {
568 for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
569 if (queues[i].head != null) {
570 EventQueueItem entry = queues[i].head;
571 queues[i].head = entry.next;
572 if (entry.next == null) {
573 queues[i].tail = null;
574 }
575 uncacheEQItem(entry);
576 return entry.event;
577 }
578 }
579 return null;
580 }
581
582 AWTEvent getNextEvent(int id) throws InterruptedException {
583 do {
584 /*
585 * SunToolkit.flushPendingEvents must be called outside
586 * of the synchronized block to avoid deadlock when
587 * event queues are nested with push()/pop().
588 */
589 SunToolkit.flushPendingEvents(appContext);
590 pushPopLock.lock();
591 try {
592 for (int i = 0; i < NUM_PRIORITIES; i++) {
593 for (EventQueueItem entry = queues[i].head, prev = null;
594 entry != null; prev = entry, entry = entry.next)
595 {
596 if (entry.event.getID() == id) {
597 if (prev == null) {
598 queues[i].head = entry.next;
599 } else {
600 prev.next = entry.next;
601 }
602 if (queues[i].tail == entry) {
603 queues[i].tail = prev;
604 }
605 uncacheEQItem(entry);
606 return entry.event;
607 }
608 }
609 }
610 waitForID = id;
611 pushPopCond.await();
612 waitForID = 0;
613 } finally {
614 pushPopLock.unlock();
615 }
616 } while(true);
617 }
618
619 /**
620 * Returns the first event on the {@code EventQueue}
621 * without removing it.
622 * @return the first event
623 */
624 public AWTEvent peekEvent() {
625 pushPopLock.lock();
626 try {
627 for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
628 if (queues[i].head != null) {
629 return queues[i].head.event;
630 }
631 }
632 } finally {
633 pushPopLock.unlock();
634 }
635
636 return null;
637 }
638
639 /**
640 * Returns the first event with the specified id, if any.
641 * @param id the id of the type of event desired
642 * @return the first event of the specified id or {@code null}
643 * if there is no such event
644 */
645 public AWTEvent peekEvent(int id) {
646 pushPopLock.lock();
647 try {
648 for (int i = NUM_PRIORITIES - 1; i >= 0; i--) {
649 EventQueueItem q = queues[i].head;
650 for (; q != null; q = q.next) {
651 if (q.event.getID() == id) {
652 return q.event;
653 }
654 }
655 }
656 } finally {
657 pushPopLock.unlock();
658 }
659
660 return null;
661 }
662
663 private static final JavaSecurityAccess javaSecurityAccess =
664 SharedSecrets.getJavaSecurityAccess();
665
666 /**
667 * Dispatches an event. The manner in which the event is
668 * dispatched depends upon the type of the event and the
669 * type of the event's source object:
670 *
671 * <table class="striped">
672 * <caption>Event types, source types, and dispatch methods</caption>
673 * <thead>
674 * <tr>
675 * <th scope="col">Event Type
676 * <th scope="col">Source Type
677 * <th scope="col">Dispatched To
678 * </thead>
679 * <tbody>
680 * <tr>
681 * <th scope="row">ActiveEvent
682 * <td>Any
683 * <td>event.dispatch()
684 * <tr>
685 * <th scope="row">Other
686 * <td>Component
687 * <td>source.dispatchEvent(AWTEvent)
688 * <tr>
689 * <th scope="row">Other
690 * <td>MenuComponent
691 * <td>source.dispatchEvent(AWTEvent)
692 * <tr>
693 * <th scope="row">Other
694 * <td>Other
695 * <td>No action (ignored)
696 * </tbody>
697 * </table>
698 *
699 * @param event an instance of {@code java.awt.AWTEvent},
700 * or a subclass of it
701 * @throws NullPointerException if {@code event} is {@code null}
702 * @since 1.2
703 */
704 protected void dispatchEvent(final AWTEvent event) {
705 final Object src = event.getSource();
706 final PrivilegedAction<Void> action = new PrivilegedAction<Void>() {
707 public Void run() {
708 // In case fwDispatcher is installed and we're already on the
709 // dispatch thread (e.g. performing DefaultKeyboardFocusManager.sendMessage),
710 // dispatch the event straight away.
711 if (fwDispatcher == null || isDispatchThreadImpl()) {
712 dispatchEventImpl(event, src);
713 } else {
714 fwDispatcher.scheduleDispatch(new Runnable() {
715 @Override
716 public void run() {
717 if (dispatchThread.filterAndCheckEvent(event)) {
718 dispatchEventImpl(event, src);
719 }
720 }
721 });
722 }
723 return null;
724 }
725 };
726
727 final AccessControlContext stack = AccessController.getContext();
728 final AccessControlContext srcAcc = getAccessControlContextFrom(src);
729 final AccessControlContext eventAcc = event.getAccessControlContext();
730 if (srcAcc == null) {
731 javaSecurityAccess.doIntersectionPrivilege(action, stack, eventAcc);
732 } else {
733 javaSecurityAccess.doIntersectionPrivilege(
734 new PrivilegedAction<Void>() {
735 public Void run() {
736 javaSecurityAccess.doIntersectionPrivilege(action, eventAcc);
737 return null;
738 }
739 }, stack, srcAcc);
740 }
741 }
742
743 private static AccessControlContext getAccessControlContextFrom(Object src) {
744 return src instanceof Component ?
745 ((Component)src).getAccessControlContext() :
746 src instanceof MenuComponent ?
747 ((MenuComponent)src).getAccessControlContext() :
748 src instanceof TrayIcon ?
749 ((TrayIcon)src).getAccessControlContext() :
750 null;
751 }
752
753 /**
754 * Called from dispatchEvent() under a correct AccessControlContext
755 */
756 private void dispatchEventImpl(final AWTEvent event, final Object src) {
757 event.isPosted = true;
758 if (event instanceof ActiveEvent) {
759 // This could become the sole method of dispatching in time.
760 setCurrentEventAndMostRecentTimeImpl(event);
761 ((ActiveEvent)event).dispatch();
762 } else if (src instanceof Component) {
763 ((Component)src).dispatchEvent(event);
764 event.dispatched();
765 } else if (src instanceof MenuComponent) {
766 ((MenuComponent)src).dispatchEvent(event);
767 } else if (src instanceof TrayIcon) {
768 ((TrayIcon)src).dispatchEvent(event);
769 } else if (src instanceof AWTAutoShutdown) {
770 if (noEvents()) {
771 dispatchThread.stopDispatching();
772 }
773 } else {
774 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
775 getEventLog().fine("Unable to dispatch event: " + event);
776 }
777 }
778 }
779
780 /**
781 * Returns the timestamp of the most recent event that had a timestamp, and
782 * that was dispatched from the {@code EventQueue} associated with the
783 * calling thread. If an event with a timestamp is currently being
784 * dispatched, its timestamp will be returned. If no events have yet
785 * been dispatched, the EventQueue's initialization time will be
786 * returned instead.In the current version of
787 * the JDK, only {@code InputEvent}s,
788 * {@code ActionEvent}s, and {@code InvocationEvent}s have
789 * timestamps; however, future versions of the JDK may add timestamps to
790 * additional event types. Note that this method should only be invoked
791 * from an application's {@link #isDispatchThread event dispatching thread}.
792 * If this method is
793 * invoked from another thread, the current system time (as reported by
794 * {@code System.currentTimeMillis()}) will be returned instead.
795 *
796 * @return the timestamp of the last {@code InputEvent},
797 * {@code ActionEvent}, or {@code InvocationEvent} to be
798 * dispatched, or {@code System.currentTimeMillis()} if this
799 * method is invoked on a thread other than an event dispatching
800 * thread
801 * @see java.awt.event.InputEvent#getWhen
802 * @see java.awt.event.ActionEvent#getWhen
803 * @see java.awt.event.InvocationEvent#getWhen
804 * @see #isDispatchThread
805 *
806 * @since 1.4
807 */
808 public static long getMostRecentEventTime() {
809 return Toolkit.getEventQueue().getMostRecentEventTimeImpl();
810 }
811 private long getMostRecentEventTimeImpl() {
812 pushPopLock.lock();
813 try {
814 return (Thread.currentThread() == dispatchThread)
815 ? mostRecentEventTime
816 : System.currentTimeMillis();
817 } finally {
818 pushPopLock.unlock();
819 }
820 }
821
822 /**
823 * @return most recent event time on all threads.
824 */
825 long getMostRecentEventTimeEx() {
826 pushPopLock.lock();
827 try {
828 return mostRecentEventTime;
829 } finally {
830 pushPopLock.unlock();
831 }
832 }
833
834 /**
835 * Returns the event currently being dispatched by the
836 * {@code EventQueue} associated with the calling thread. This is
837 * useful if a method needs access to the event, but was not designed to
838 * receive a reference to it as an argument. Note that this method should
839 * only be invoked from an application's event dispatching thread. If this
840 * method is invoked from another thread, null will be returned.
841 *
842 * @return the event currently being dispatched, or null if this method is
843 * invoked on a thread other than an event dispatching thread
844 * @since 1.4
845 */
846 public static AWTEvent getCurrentEvent() {
847 return Toolkit.getEventQueue().getCurrentEventImpl();
848 }
849 private AWTEvent getCurrentEventImpl() {
850 pushPopLock.lock();
851 try {
852 return (Thread.currentThread() == dispatchThread)
853 ? currentEvent.get()
854 : null;
855 } finally {
856 pushPopLock.unlock();
857 }
858 }
859
860 /**
861 * Replaces the existing {@code EventQueue} with the specified one.
862 * Any pending events are transferred to the new {@code EventQueue}
863 * for processing by it.
864 *
865 * @param newEventQueue an {@code EventQueue}
866 * (or subclass thereof) instance to be use
867 * @see java.awt.EventQueue#pop
868 * @throws NullPointerException if {@code newEventQueue} is {@code null}
869 * @since 1.2
870 */
871 public void push(EventQueue newEventQueue) {
872 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
873 getEventLog().fine("EventQueue.push(" + newEventQueue + ")");
874 }
875
876 pushPopLock.lock();
877 try {
878 EventQueue topQueue = this;
879 while (topQueue.nextQueue != null) {
880 topQueue = topQueue.nextQueue;
881 }
882 if (topQueue.fwDispatcher != null) {
883 throw new RuntimeException("push() to queue with fwDispatcher");
884 }
885 if ((topQueue.dispatchThread != null) &&
886 (topQueue.dispatchThread.getEventQueue() == this))
887 {
888 newEventQueue.dispatchThread = topQueue.dispatchThread;
889 topQueue.dispatchThread.setEventQueue(newEventQueue);
890 }
891
892 // Transfer all events forward to new EventQueue.
893 while (topQueue.peekEvent() != null) {
894 try {
895 // Use getNextEventPrivate() as it doesn't call flushPendingEvents()
896 newEventQueue.postEventPrivate(topQueue.getNextEventPrivate());
897 } catch (InterruptedException ie) {
898 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
899 getEventLog().fine("Interrupted push", ie);
900 }
901 }
902 }
903
904 if (topQueue.dispatchThread != null) {
905 // Wake up EDT waiting in getNextEvent(), so it can
906 // pick up a new EventQueue. Post the waking event before
907 // topQueue.nextQueue is assigned, otherwise the event would
908 // go newEventQueue
909 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
910 }
911
912 newEventQueue.previousQueue = topQueue;
913 topQueue.nextQueue = newEventQueue;
914
915 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == topQueue) {
916 appContext.put(AppContext.EVENT_QUEUE_KEY, newEventQueue);
917 }
918
919 pushPopCond.signalAll();
920 } finally {
921 pushPopLock.unlock();
922 }
923 }
924
925 /**
926 * Stops dispatching events using this {@code EventQueue}.
927 * Any pending events are transferred to the previous
928 * {@code EventQueue} for processing.
929 * <p>
930 * Warning: To avoid deadlock, do not declare this method
931 * synchronized in a subclass.
932 *
933 * @exception EmptyStackException if no previous push was made
934 * on this {@code EventQueue}
935 * @see java.awt.EventQueue#push
936 * @since 1.2
937 */
938 protected void pop() throws EmptyStackException {
939 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
940 getEventLog().fine("EventQueue.pop(" + this + ")");
941 }
942
943 pushPopLock.lock();
944 try {
945 EventQueue topQueue = this;
946 while (topQueue.nextQueue != null) {
947 topQueue = topQueue.nextQueue;
948 }
949 EventQueue prevQueue = topQueue.previousQueue;
950 if (prevQueue == null) {
951 throw new EmptyStackException();
952 }
953
954 topQueue.previousQueue = null;
955 prevQueue.nextQueue = null;
956
957 // Transfer all events back to previous EventQueue.
958 while (topQueue.peekEvent() != null) {
959 try {
960 prevQueue.postEventPrivate(topQueue.getNextEventPrivate());
961 } catch (InterruptedException ie) {
962 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
963 getEventLog().fine("Interrupted pop", ie);
964 }
965 }
966 }
967
968 if ((topQueue.dispatchThread != null) &&
969 (topQueue.dispatchThread.getEventQueue() == this))
970 {
971 prevQueue.dispatchThread = topQueue.dispatchThread;
972 topQueue.dispatchThread.setEventQueue(prevQueue);
973 }
974
975 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this) {
976 appContext.put(AppContext.EVENT_QUEUE_KEY, prevQueue);
977 }
978
979 // Wake up EDT waiting in getNextEvent(), so it can
980 // pick up a new EventQueue
981 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
982
983 pushPopCond.signalAll();
984 } finally {
985 pushPopLock.unlock();
986 }
987 }
988
989 /**
990 * Creates a new {@code secondary loop} associated with this
991 * event queue. Use the {@link SecondaryLoop#enter} and
992 * {@link SecondaryLoop#exit} methods to start and stop the
993 * event loop and dispatch the events from this queue.
994 *
995 * @return secondaryLoop A new secondary loop object, which can
996 * be used to launch a new nested event
997 * loop and dispatch events from this queue
998 *
999 * @see SecondaryLoop#enter
1000 * @see SecondaryLoop#exit
1001 *
1002 * @since 1.7
1003 */
1004 public SecondaryLoop createSecondaryLoop() {
1005 return createSecondaryLoop(null, null, 0);
1006 }
1007
1008 private class FwSecondaryLoopWrapper implements SecondaryLoop {
1009 final private SecondaryLoop loop;
1010 final private EventFilter filter;
1011
1012 public FwSecondaryLoopWrapper(SecondaryLoop loop, EventFilter filter) {
1013 this.loop = loop;
1014 this.filter = filter;
1015 }
1016
1017 @Override
1018 public boolean enter() {
1019 if (filter != null) {
1020 dispatchThread.addEventFilter(filter);
1021 }
1022 return loop.enter();
1023 }
1024
1025 @Override
1026 public boolean exit() {
1027 if (filter != null) {
1028 dispatchThread.removeEventFilter(filter);
1029 }
1030 return loop.exit();
1031 }
1032 }
1033
1034 SecondaryLoop createSecondaryLoop(Conditional cond, EventFilter filter, long interval) {
1035 pushPopLock.lock();
1036 try {
1037 if (nextQueue != null) {
1038 // Forward the request to the top of EventQueue stack
1039 return nextQueue.createSecondaryLoop(cond, filter, interval);
1040 }
1041 if (fwDispatcher != null) {
1042 return new FwSecondaryLoopWrapper(fwDispatcher.createSecondaryLoop(), filter);
1043 }
1044 if (dispatchThread == null) {
1045 initDispatchThread();
1046 }
1047 return new WaitDispatchSupport(dispatchThread, cond, filter, interval);
1048 } finally {
1049 pushPopLock.unlock();
1050 }
1051 }
1052
1053 /**
1054 * Returns true if the calling thread is
1055 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1056 * dispatch thread. Use this method to ensure that a particular
1057 * task is being executed (or not being) there.
1058 * <p>
1059 * Note: use the {@link #invokeLater} or {@link #invokeAndWait}
1060 * methods to execute a task in
1061 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1062 * dispatch thread.
1063 *
1064 * @return true if running in
1065 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1066 * dispatch thread
1067 * @see #invokeLater
1068 * @see #invokeAndWait
1069 * @see Toolkit#getSystemEventQueue
1070 * @since 1.2
1071 */
1072 public static boolean isDispatchThread() {
1073 EventQueue eq = Toolkit.getEventQueue();
1074 return eq.isDispatchThreadImpl();
1075 }
1076
1077 final boolean isDispatchThreadImpl() {
1078 EventQueue eq = this;
1079 pushPopLock.lock();
1080 try {
1081 EventQueue next = eq.nextQueue;
1082 while (next != null) {
1083 eq = next;
1084 next = eq.nextQueue;
1085 }
1086 if (eq.fwDispatcher != null) {
1087 return eq.fwDispatcher.isDispatchThread();
1088 }
1089 return (Thread.currentThread() == eq.dispatchThread);
1090 } finally {
1091 pushPopLock.unlock();
1092 }
1093 }
1094
1095 final void initDispatchThread() {
1096 pushPopLock.lock();
1097 try {
1098 if (dispatchThread == null && !threadGroup.isDestroyed() && !appContext.isDisposed()) {
1099 dispatchThread = AccessController.doPrivileged(
1100 new PrivilegedAction<EventDispatchThread>() {
1101 public EventDispatchThread run() {
1102 EventDispatchThread t =
1103 new EventDispatchThread(threadGroup,
1104 name,
1105 EventQueue.this);
1106 t.setContextClassLoader(classLoader);
1107 t.setPriority(Thread.NORM_PRIORITY + 1);
1108 t.setDaemon(false);
1109 AWTAutoShutdown.getInstance().notifyThreadBusy(t);
1110 return t;
1111 }
1112 }
1113 );
1114 dispatchThread.start();
1115 }
1116 } finally {
1117 pushPopLock.unlock();
1118 }
1119 }
1120
1121 final void detachDispatchThread(EventDispatchThread edt) {
1122 /*
1123 * Minimize discard possibility for non-posted events
1124 */
1125 SunToolkit.flushPendingEvents(appContext);
1126 /*
1127 * This synchronized block is to secure that the event dispatch
1128 * thread won't die in the middle of posting a new event to the
1129 * associated event queue. It is important because we notify
1130 * that the event dispatch thread is busy after posting a new event
1131 * to its queue, so the EventQueue.dispatchThread reference must
1132 * be valid at that point.
1133 */
1134 pushPopLock.lock();
1135 try {
1136 if (edt == dispatchThread) {
1137 dispatchThread = null;
1138 }
1139 AWTAutoShutdown.getInstance().notifyThreadFree(edt);
1140 /*
1141 * Event was posted after EDT events pumping had stopped, so start
1142 * another EDT to handle this event
1143 */
1144 if (peekEvent() != null) {
1145 initDispatchThread();
1146 }
1147 } finally {
1148 pushPopLock.unlock();
1149 }
1150 }
1151
1152 /*
1153 * Gets the {@code EventDispatchThread} for this
1154 * {@code EventQueue}.
1155 * @return the event dispatch thread associated with this event queue
1156 * or {@code null} if this event queue doesn't have a
1157 * working thread associated with it
1158 * @see java.awt.EventQueue#initDispatchThread
1159 * @see java.awt.EventQueue#detachDispatchThread
1160 */
1161 final EventDispatchThread getDispatchThread() {
1162 pushPopLock.lock();
1163 try {
1164 return dispatchThread;
1165 } finally {
1166 pushPopLock.unlock();
1167 }
1168 }
1169
1170 /*
1171 * Removes any pending events for the specified source object.
1172 * If removeAllEvents parameter is {@code true} then all
1173 * events for the specified source object are removed, if it
1174 * is {@code false} then {@code SequencedEvent}, {@code SentEvent},
1175 * {@code FocusEvent}, {@code WindowEvent}, {@code KeyEvent},
1176 * and {@code InputMethodEvent} are kept in the queue, but all other
1177 * events are removed.
1178 *
1179 * This method is normally called by the source's
1180 * {@code removeNotify} method.
1181 */
1182 final void removeSourceEvents(Object source, boolean removeAllEvents) {
1183 SunToolkit.flushPendingEvents(appContext);
1184 pushPopLock.lock();
1185 try {
1186 for (int i = 0; i < NUM_PRIORITIES; i++) {
1187 EventQueueItem entry = queues[i].head;
1188 EventQueueItem prev = null;
1189 while (entry != null) {
1190 if ((entry.event.getSource() == source)
1191 && (removeAllEvents
1192 || ! (entry.event instanceof SequencedEvent
1193 || entry.event instanceof SentEvent
1194 || entry.event instanceof FocusEvent
1195 || entry.event instanceof WindowEvent
1196 || entry.event instanceof KeyEvent
1197 || entry.event instanceof InputMethodEvent)))
1198 {
1199 if (entry.event instanceof SequencedEvent) {
1200 ((SequencedEvent)entry.event).dispose();
1201 }
1202 if (entry.event instanceof SentEvent) {
1203 ((SentEvent)entry.event).dispose();
1204 }
1205 if (entry.event instanceof InvocationEvent) {
1206 AWTAccessor.getInvocationEventAccessor()
1207 .dispose((InvocationEvent)entry.event);
1208 }
1209 if (entry.event instanceof SunDropTargetEvent) {
1210 ((SunDropTargetEvent)entry.event).dispose();
1211 }
1212 if (prev == null) {
1213 queues[i].head = entry.next;
1214 } else {
1215 prev.next = entry.next;
1216 }
1217 uncacheEQItem(entry);
1218 } else {
1219 prev = entry;
1220 }
1221 entry = entry.next;
1222 }
1223 queues[i].tail = prev;
1224 }
1225 } finally {
1226 pushPopLock.unlock();
1227 }
1228 }
1229
1230 synchronized long getMostRecentKeyEventTime() {
1231 pushPopLock.lock();
1232 try {
1233 return mostRecentKeyEventTime;
1234 } finally {
1235 pushPopLock.unlock();
1236 }
1237 }
1238
1239 static void setCurrentEventAndMostRecentTime(AWTEvent e) {
1240 Toolkit.getEventQueue().setCurrentEventAndMostRecentTimeImpl(e);
1241 }
1242 private void setCurrentEventAndMostRecentTimeImpl(AWTEvent e) {
1243 pushPopLock.lock();
1244 try {
1245 if (Thread.currentThread() != dispatchThread) {
1246 return;
1247 }
1248
1249 currentEvent = new WeakReference<>(e);
1250
1251 // This series of 'instanceof' checks should be replaced with a
1252 // polymorphic type (for example, an interface which declares a
1253 // getWhen() method). However, this would require us to make such
1254 // a type public, or to place it in sun.awt. Both of these approaches
1255 // have been frowned upon. So for now, we hack.
1256 //
1257 // In tiger, we will probably give timestamps to all events, so this
1258 // will no longer be an issue.
1259 long mostRecentEventTime2 = Long.MIN_VALUE;
1260 if (e instanceof InputEvent) {
1261 InputEvent ie = (InputEvent)e;
1262 mostRecentEventTime2 = ie.getWhen();
1263 if (e instanceof KeyEvent) {
1264 mostRecentKeyEventTime = ie.getWhen();
1265 }
1266 } else if (e instanceof InputMethodEvent) {
1267 InputMethodEvent ime = (InputMethodEvent)e;
1268 mostRecentEventTime2 = ime.getWhen();
1269 } else if (e instanceof ActionEvent) {
1270 ActionEvent ae = (ActionEvent)e;
1271 mostRecentEventTime2 = ae.getWhen();
1272 } else if (e instanceof InvocationEvent) {
1273 InvocationEvent ie = (InvocationEvent)e;
1274 mostRecentEventTime2 = ie.getWhen();
1275 }
1276 mostRecentEventTime = Math.max(mostRecentEventTime, mostRecentEventTime2);
1277 } finally {
1278 pushPopLock.unlock();
1279 }
1280 }
1281
1282 /**
1283 * Causes {@code runnable} to have its {@code run}
1284 * method called in the {@link #isDispatchThread dispatch thread} of
1285 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1286 * This will happen after all pending events are processed.
1287 *
1288 * @param runnable the {@code Runnable} whose {@code run}
1289 * method should be executed
1290 * asynchronously in the
1291 * {@link #isDispatchThread event dispatch thread}
1292 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1293 * @see #invokeAndWait
1294 * @see Toolkit#getSystemEventQueue
1295 * @see #isDispatchThread
1296 * @since 1.2
1297 */
1298 public static void invokeLater(Runnable runnable) {
1299 Toolkit.getEventQueue().postEvent(
1300 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
1301 }
1302
1303 /**
1304 * Causes {@code runnable} to have its {@code run}
1305 * method called in the {@link #isDispatchThread dispatch thread} of
1306 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1307 * This will happen after all pending events are processed.
1308 * The call blocks until this has happened. This method
1309 * will throw an Error if called from the
1310 * {@link #isDispatchThread event dispatcher thread}.
1311 *
1312 * @param runnable the {@code Runnable} whose {@code run}
1313 * method should be executed
1314 * synchronously in the
1315 * {@link #isDispatchThread event dispatch thread}
1316 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1317 * @exception InterruptedException if any thread has
1318 * interrupted this thread
1319 * @exception InvocationTargetException if an throwable is thrown
1320 * when running {@code runnable}
1321 * @see #invokeLater
1322 * @see Toolkit#getSystemEventQueue
1323 * @see #isDispatchThread
1324 * @since 1.2
1325 */
1326 public static void invokeAndWait(Runnable runnable)
1327 throws InterruptedException, InvocationTargetException
1328 {
1329 invokeAndWait(Toolkit.getDefaultToolkit(), runnable);
1330 }
1331
1332 static void invokeAndWait(Object source, Runnable runnable)
1333 throws InterruptedException, InvocationTargetException
1334 {
1335 if (EventQueue.isDispatchThread()) {
1336 throw new Error("Cannot call invokeAndWait from the event dispatcher thread");
1337 }
1338
1339 class AWTInvocationLock {}
1340 Object lock = new AWTInvocationLock();
1341
1342 InvocationEvent event =
1343 new InvocationEvent(source, runnable, lock, true);
1344
1345 synchronized (lock) {
1346 Toolkit.getEventQueue().postEvent(event);
1347 while (!event.isDispatched()) {
1348 lock.wait();
1349 }
1350 }
1351
1352 Throwable eventThrowable = event.getThrowable();
1353 if (eventThrowable != null) {
1354 throw new InvocationTargetException(eventThrowable);
1355 }
1356 }
1357
1358 /*
1359 * Called from PostEventQueue.postEvent to notify that a new event
1360 * appeared. First it proceeds to the EventQueue on the top of the
1361 * stack, then notifies the associated dispatch thread if it exists
1362 * or starts a new one otherwise.
1363 */
1364 private void wakeup(boolean isShutdown) {
1365 pushPopLock.lock();
1366 try {
1367 if (nextQueue != null) {
1368 // Forward call to the top of EventQueue stack.
1369 nextQueue.wakeup(isShutdown);
1370 } else if (dispatchThread != null) {
1371 pushPopCond.signalAll();
1372 } else if (!isShutdown) {
1373 initDispatchThread();
1374 }
1375 } finally {
1376 pushPopLock.unlock();
1377 }
1378 }
1379
1380 // The method is used by AWTAccessor for javafx/AWT single threaded mode.
1381 private void setFwDispatcher(FwDispatcher dispatcher) {
1382 if (nextQueue != null) {
1383 nextQueue.setFwDispatcher(dispatcher);
1384 } else {
1385 fwDispatcher = dispatcher;
1386 }
1387 }
1388 }
1389
1390 /**
1391 * The Queue object holds pointers to the beginning and end of one internal
1392 * queue. An EventQueue object is composed of multiple internal Queues, one
1393 * for each priority supported by the EventQueue. All Events on a particular
1394 * internal Queue have identical priority.
1395 */
1396 class Queue {
1397 EventQueueItem head;
1398 EventQueueItem tail;
1399 }