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 dependant 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 style="display:none">Event types, source types, and dispatch
673 * methods</caption>
674 * <thead>
675 * <tr>
676 * <th>Event Type</th>
677 * <th>Source Type</th>
678 * <th>Dispatched To</th>
679 * </tr>
680 * </thead>
681 * <tbody>
682 * <tr>
683 * <td>ActiveEvent</td>
684 * <td>Any</td>
685 * <td>event.dispatch()</td>
686 * </tr>
687 * <tr>
688 * <td>Other</td>
689 * <td>Component</td>
690 * <td>source.dispatchEvent(AWTEvent)</td>
691 * </tr>
692 * <tr>
693 * <td>Other</td>
694 * <td>MenuComponent</td>
695 * <td>source.dispatchEvent(AWTEvent)</td>
696 * </tr>
697 * <tr>
698 * <td>Other</td>
699 * <td>Other</td>
700 * <td>No action (ignored)</td>
701 * </tr>
702 * </tbody>
703 * </table>
704 *
705 * @param event an instance of {@code java.awt.AWTEvent},
706 * or a subclass of it
707 * @throws NullPointerException if {@code event} is {@code null}
708 * @since 1.2
709 */
710 protected void dispatchEvent(final AWTEvent event) {
711 final Object src = event.getSource();
712 final PrivilegedAction<Void> action = new PrivilegedAction<Void>() {
713 public Void run() {
714 // In case fwDispatcher is installed and we're already on the
715 // dispatch thread (e.g. performing DefaultKeyboardFocusManager.sendMessage),
716 // dispatch the event straight away.
717 if (fwDispatcher == null || isDispatchThreadImpl()) {
718 dispatchEventImpl(event, src);
719 } else {
720 fwDispatcher.scheduleDispatch(new Runnable() {
721 @Override
722 public void run() {
723 dispatchEventImpl(event, src);
724 }
725 });
726 }
727 return null;
728 }
729 };
730
731 final AccessControlContext stack = AccessController.getContext();
732 final AccessControlContext srcAcc = getAccessControlContextFrom(src);
733 final AccessControlContext eventAcc = event.getAccessControlContext();
734 if (srcAcc == null) {
735 javaSecurityAccess.doIntersectionPrivilege(action, stack, eventAcc);
736 } else {
737 javaSecurityAccess.doIntersectionPrivilege(
738 new PrivilegedAction<Void>() {
739 public Void run() {
740 javaSecurityAccess.doIntersectionPrivilege(action, eventAcc);
741 return null;
742 }
743 }, stack, srcAcc);
744 }
745 }
746
747 private static AccessControlContext getAccessControlContextFrom(Object src) {
748 return src instanceof Component ?
749 ((Component)src).getAccessControlContext() :
750 src instanceof MenuComponent ?
751 ((MenuComponent)src).getAccessControlContext() :
752 src instanceof TrayIcon ?
753 ((TrayIcon)src).getAccessControlContext() :
754 null;
755 }
756
757 /**
758 * Called from dispatchEvent() under a correct AccessControlContext
759 */
760 private void dispatchEventImpl(final AWTEvent event, final Object src) {
761 event.isPosted = true;
762 if (event instanceof ActiveEvent) {
763 // This could become the sole method of dispatching in time.
764 setCurrentEventAndMostRecentTimeImpl(event);
765 ((ActiveEvent)event).dispatch();
766 } else if (src instanceof Component) {
767 ((Component)src).dispatchEvent(event);
768 event.dispatched();
769 } else if (src instanceof MenuComponent) {
770 ((MenuComponent)src).dispatchEvent(event);
771 } else if (src instanceof TrayIcon) {
772 ((TrayIcon)src).dispatchEvent(event);
773 } else if (src instanceof AWTAutoShutdown) {
774 if (noEvents()) {
775 dispatchThread.stopDispatching();
776 }
777 } else {
778 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
779 getEventLog().fine("Unable to dispatch event: " + event);
780 }
781 }
782 }
783
784 /**
785 * Returns the timestamp of the most recent event that had a timestamp, and
786 * that was dispatched from the {@code EventQueue} associated with the
787 * calling thread. If an event with a timestamp is currently being
788 * dispatched, its timestamp will be returned. If no events have yet
789 * been dispatched, the EventQueue's initialization time will be
790 * returned instead.In the current version of
791 * the JDK, only {@code InputEvent}s,
792 * {@code ActionEvent}s, and {@code InvocationEvent}s have
793 * timestamps; however, future versions of the JDK may add timestamps to
794 * additional event types. Note that this method should only be invoked
795 * from an application's {@link #isDispatchThread event dispatching thread}.
796 * If this method is
797 * invoked from another thread, the current system time (as reported by
798 * {@code System.currentTimeMillis()}) will be returned instead.
799 *
800 * @return the timestamp of the last {@code InputEvent},
801 * {@code ActionEvent}, or {@code InvocationEvent} to be
802 * dispatched, or {@code System.currentTimeMillis()} if this
803 * method is invoked on a thread other than an event dispatching
804 * thread
805 * @see java.awt.event.InputEvent#getWhen
806 * @see java.awt.event.ActionEvent#getWhen
807 * @see java.awt.event.InvocationEvent#getWhen
808 * @see #isDispatchThread
809 *
810 * @since 1.4
811 */
812 public static long getMostRecentEventTime() {
813 return Toolkit.getEventQueue().getMostRecentEventTimeImpl();
814 }
815 private long getMostRecentEventTimeImpl() {
816 pushPopLock.lock();
817 try {
818 return (Thread.currentThread() == dispatchThread)
819 ? mostRecentEventTime
820 : System.currentTimeMillis();
821 } finally {
822 pushPopLock.unlock();
823 }
824 }
825
826 /**
827 * @return most recent event time on all threads.
828 */
829 long getMostRecentEventTimeEx() {
830 pushPopLock.lock();
831 try {
832 return mostRecentEventTime;
833 } finally {
834 pushPopLock.unlock();
835 }
836 }
837
838 /**
839 * Returns the event currently being dispatched by the
840 * {@code EventQueue} associated with the calling thread. This is
841 * useful if a method needs access to the event, but was not designed to
842 * receive a reference to it as an argument. Note that this method should
843 * only be invoked from an application's event dispatching thread. If this
844 * method is invoked from another thread, null will be returned.
845 *
846 * @return the event currently being dispatched, or null if this method is
847 * invoked on a thread other than an event dispatching thread
848 * @since 1.4
849 */
850 public static AWTEvent getCurrentEvent() {
851 return Toolkit.getEventQueue().getCurrentEventImpl();
852 }
853 private AWTEvent getCurrentEventImpl() {
854 pushPopLock.lock();
855 try {
856 return (Thread.currentThread() == dispatchThread)
857 ? currentEvent.get()
858 : null;
859 } finally {
860 pushPopLock.unlock();
861 }
862 }
863
864 /**
865 * Replaces the existing {@code EventQueue} with the specified one.
866 * Any pending events are transferred to the new {@code EventQueue}
867 * for processing by it.
868 *
869 * @param newEventQueue an {@code EventQueue}
870 * (or subclass thereof) instance to be use
871 * @see java.awt.EventQueue#pop
872 * @throws NullPointerException if {@code newEventQueue} is {@code null}
873 * @since 1.2
874 */
875 public void push(EventQueue newEventQueue) {
876 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
877 getEventLog().fine("EventQueue.push(" + newEventQueue + ")");
878 }
879
880 pushPopLock.lock();
881 try {
882 EventQueue topQueue = this;
883 while (topQueue.nextQueue != null) {
884 topQueue = topQueue.nextQueue;
885 }
886 if (topQueue.fwDispatcher != null) {
887 throw new RuntimeException("push() to queue with fwDispatcher");
888 }
889 if ((topQueue.dispatchThread != null) &&
890 (topQueue.dispatchThread.getEventQueue() == this))
891 {
892 newEventQueue.dispatchThread = topQueue.dispatchThread;
893 topQueue.dispatchThread.setEventQueue(newEventQueue);
894 }
895
896 // Transfer all events forward to new EventQueue.
897 while (topQueue.peekEvent() != null) {
898 try {
899 // Use getNextEventPrivate() as it doesn't call flushPendingEvents()
900 newEventQueue.postEventPrivate(topQueue.getNextEventPrivate());
901 } catch (InterruptedException ie) {
902 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
903 getEventLog().fine("Interrupted push", ie);
904 }
905 }
906 }
907
908 if (topQueue.dispatchThread != null) {
909 // Wake up EDT waiting in getNextEvent(), so it can
910 // pick up a new EventQueue. Post the waking event before
911 // topQueue.nextQueue is assigned, otherwise the event would
912 // go newEventQueue
913 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
914 }
915
916 newEventQueue.previousQueue = topQueue;
917 topQueue.nextQueue = newEventQueue;
918
919 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == topQueue) {
920 appContext.put(AppContext.EVENT_QUEUE_KEY, newEventQueue);
921 }
922
923 pushPopCond.signalAll();
924 } finally {
925 pushPopLock.unlock();
926 }
927 }
928
929 /**
930 * Stops dispatching events using this {@code EventQueue}.
931 * Any pending events are transferred to the previous
932 * {@code EventQueue} for processing.
933 * <p>
934 * Warning: To avoid deadlock, do not declare this method
935 * synchronized in a subclass.
936 *
937 * @exception EmptyStackException if no previous push was made
938 * on this {@code EventQueue}
939 * @see java.awt.EventQueue#push
940 * @since 1.2
941 */
942 protected void pop() throws EmptyStackException {
943 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
944 getEventLog().fine("EventQueue.pop(" + this + ")");
945 }
946
947 pushPopLock.lock();
948 try {
949 EventQueue topQueue = this;
950 while (topQueue.nextQueue != null) {
951 topQueue = topQueue.nextQueue;
952 }
953 EventQueue prevQueue = topQueue.previousQueue;
954 if (prevQueue == null) {
955 throw new EmptyStackException();
956 }
957
958 topQueue.previousQueue = null;
959 prevQueue.nextQueue = null;
960
961 // Transfer all events back to previous EventQueue.
962 while (topQueue.peekEvent() != null) {
963 try {
964 prevQueue.postEventPrivate(topQueue.getNextEventPrivate());
965 } catch (InterruptedException ie) {
966 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
967 getEventLog().fine("Interrupted pop", ie);
968 }
969 }
970 }
971
972 if ((topQueue.dispatchThread != null) &&
973 (topQueue.dispatchThread.getEventQueue() == this))
974 {
975 prevQueue.dispatchThread = topQueue.dispatchThread;
976 topQueue.dispatchThread.setEventQueue(prevQueue);
977 }
978
979 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this) {
980 appContext.put(AppContext.EVENT_QUEUE_KEY, prevQueue);
981 }
982
983 // Wake up EDT waiting in getNextEvent(), so it can
984 // pick up a new EventQueue
985 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
986
987 pushPopCond.signalAll();
988 } finally {
989 pushPopLock.unlock();
990 }
991 }
992
993 /**
994 * Creates a new {@code secondary loop} associated with this
995 * event queue. Use the {@link SecondaryLoop#enter} and
996 * {@link SecondaryLoop#exit} methods to start and stop the
997 * event loop and dispatch the events from this queue.
998 *
999 * @return secondaryLoop A new secondary loop object, which can
1000 * be used to launch a new nested event
1001 * loop and dispatch events from this queue
1002 *
1003 * @see SecondaryLoop#enter
1004 * @see SecondaryLoop#exit
1005 *
1006 * @since 1.7
1007 */
1008 public SecondaryLoop createSecondaryLoop() {
1009 return createSecondaryLoop(null, null, 0);
1010 }
1011
1012 SecondaryLoop createSecondaryLoop(Conditional cond, EventFilter filter, long interval) {
1013 pushPopLock.lock();
1014 try {
1015 if (nextQueue != null) {
1016 // Forward the request to the top of EventQueue stack
1017 return nextQueue.createSecondaryLoop(cond, filter, interval);
1018 }
1019 if (fwDispatcher != null) {
1020 return fwDispatcher.createSecondaryLoop();
1021 }
1022 if (dispatchThread == null) {
1023 initDispatchThread();
1024 }
1025 return new WaitDispatchSupport(dispatchThread, cond, filter, interval);
1026 } finally {
1027 pushPopLock.unlock();
1028 }
1029 }
1030
1031 /**
1032 * Returns true if the calling thread is
1033 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1034 * dispatch thread. Use this method to ensure that a particular
1035 * task is being executed (or not being) there.
1036 * <p>
1037 * Note: use the {@link #invokeLater} or {@link #invokeAndWait}
1038 * methods to execute a task in
1039 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1040 * dispatch thread.
1041 *
1042 * @return true if running in
1043 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1044 * dispatch thread
1045 * @see #invokeLater
1046 * @see #invokeAndWait
1047 * @see Toolkit#getSystemEventQueue
1048 * @since 1.2
1049 */
1050 public static boolean isDispatchThread() {
1051 EventQueue eq = Toolkit.getEventQueue();
1052 return eq.isDispatchThreadImpl();
1053 }
1054
1055 final boolean isDispatchThreadImpl() {
1056 EventQueue eq = this;
1057 pushPopLock.lock();
1058 try {
1059 EventQueue next = eq.nextQueue;
1060 while (next != null) {
1061 eq = next;
1062 next = eq.nextQueue;
1063 }
1064 if (eq.fwDispatcher != null) {
1065 return eq.fwDispatcher.isDispatchThread();
1066 }
1067 return (Thread.currentThread() == eq.dispatchThread);
1068 } finally {
1069 pushPopLock.unlock();
1070 }
1071 }
1072
1073 final void initDispatchThread() {
1074 pushPopLock.lock();
1075 try {
1076 if (dispatchThread == null && !threadGroup.isDestroyed() && !appContext.isDisposed()) {
1077 dispatchThread = AccessController.doPrivileged(
1078 new PrivilegedAction<EventDispatchThread>() {
1079 public EventDispatchThread run() {
1080 EventDispatchThread t =
1081 new EventDispatchThread(threadGroup,
1082 name,
1083 EventQueue.this);
1084 t.setContextClassLoader(classLoader);
1085 t.setPriority(Thread.NORM_PRIORITY + 1);
1086 t.setDaemon(false);
1087 AWTAutoShutdown.getInstance().notifyThreadBusy(t);
1088 return t;
1089 }
1090 }
1091 );
1092 dispatchThread.start();
1093 }
1094 } finally {
1095 pushPopLock.unlock();
1096 }
1097 }
1098
1099 final void detachDispatchThread(EventDispatchThread edt) {
1100 /*
1101 * Minimize discard possibility for non-posted events
1102 */
1103 SunToolkit.flushPendingEvents(appContext);
1104 /*
1105 * This synchronized block is to secure that the event dispatch
1106 * thread won't die in the middle of posting a new event to the
1107 * associated event queue. It is important because we notify
1108 * that the event dispatch thread is busy after posting a new event
1109 * to its queue, so the EventQueue.dispatchThread reference must
1110 * be valid at that point.
1111 */
1112 pushPopLock.lock();
1113 try {
1114 if (edt == dispatchThread) {
1115 dispatchThread = null;
1116 }
1117 AWTAutoShutdown.getInstance().notifyThreadFree(edt);
1118 /*
1119 * Event was posted after EDT events pumping had stopped, so start
1120 * another EDT to handle this event
1121 */
1122 if (peekEvent() != null) {
1123 initDispatchThread();
1124 }
1125 } finally {
1126 pushPopLock.unlock();
1127 }
1128 }
1129
1130 /*
1131 * Gets the {@code EventDispatchThread} for this
1132 * {@code EventQueue}.
1133 * @return the event dispatch thread associated with this event queue
1134 * or {@code null} if this event queue doesn't have a
1135 * working thread associated with it
1136 * @see java.awt.EventQueue#initDispatchThread
1137 * @see java.awt.EventQueue#detachDispatchThread
1138 */
1139 final EventDispatchThread getDispatchThread() {
1140 pushPopLock.lock();
1141 try {
1142 return dispatchThread;
1143 } finally {
1144 pushPopLock.unlock();
1145 }
1146 }
1147
1148 /*
1149 * Removes any pending events for the specified source object.
1150 * If removeAllEvents parameter is {@code true} then all
1151 * events for the specified source object are removed, if it
1152 * is {@code false} then {@code SequencedEvent}, {@code SentEvent},
1153 * {@code FocusEvent}, {@code WindowEvent}, {@code KeyEvent},
1154 * and {@code InputMethodEvent} are kept in the queue, but all other
1155 * events are removed.
1156 *
1157 * This method is normally called by the source's
1158 * {@code removeNotify} method.
1159 */
1160 final void removeSourceEvents(Object source, boolean removeAllEvents) {
1161 SunToolkit.flushPendingEvents(appContext);
1162 pushPopLock.lock();
1163 try {
1164 for (int i = 0; i < NUM_PRIORITIES; i++) {
1165 EventQueueItem entry = queues[i].head;
1166 EventQueueItem prev = null;
1167 while (entry != null) {
1168 if ((entry.event.getSource() == source)
1169 && (removeAllEvents
1170 || ! (entry.event instanceof SequencedEvent
1171 || entry.event instanceof SentEvent
1172 || entry.event instanceof FocusEvent
1173 || entry.event instanceof WindowEvent
1174 || entry.event instanceof KeyEvent
1175 || entry.event instanceof InputMethodEvent)))
1176 {
1177 if (entry.event instanceof SequencedEvent) {
1178 ((SequencedEvent)entry.event).dispose();
1179 }
1180 if (entry.event instanceof SentEvent) {
1181 ((SentEvent)entry.event).dispose();
1182 }
1183 if (entry.event instanceof InvocationEvent) {
1184 AWTAccessor.getInvocationEventAccessor()
1185 .dispose((InvocationEvent)entry.event);
1186 }
1187 if (prev == null) {
1188 queues[i].head = entry.next;
1189 } else {
1190 prev.next = entry.next;
1191 }
1192 uncacheEQItem(entry);
1193 } else {
1194 prev = entry;
1195 }
1196 entry = entry.next;
1197 }
1198 queues[i].tail = prev;
1199 }
1200 } finally {
1201 pushPopLock.unlock();
1202 }
1203 }
1204
1205 synchronized long getMostRecentKeyEventTime() {
1206 pushPopLock.lock();
1207 try {
1208 return mostRecentKeyEventTime;
1209 } finally {
1210 pushPopLock.unlock();
1211 }
1212 }
1213
1214 static void setCurrentEventAndMostRecentTime(AWTEvent e) {
1215 Toolkit.getEventQueue().setCurrentEventAndMostRecentTimeImpl(e);
1216 }
1217 private void setCurrentEventAndMostRecentTimeImpl(AWTEvent e) {
1218 pushPopLock.lock();
1219 try {
1220 if (Thread.currentThread() != dispatchThread) {
1221 return;
1222 }
1223
1224 currentEvent = new WeakReference<>(e);
1225
1226 // This series of 'instanceof' checks should be replaced with a
1227 // polymorphic type (for example, an interface which declares a
1228 // getWhen() method). However, this would require us to make such
1229 // a type public, or to place it in sun.awt. Both of these approaches
1230 // have been frowned upon. So for now, we hack.
1231 //
1232 // In tiger, we will probably give timestamps to all events, so this
1233 // will no longer be an issue.
1234 long mostRecentEventTime2 = Long.MIN_VALUE;
1235 if (e instanceof InputEvent) {
1236 InputEvent ie = (InputEvent)e;
1237 mostRecentEventTime2 = ie.getWhen();
1238 if (e instanceof KeyEvent) {
1239 mostRecentKeyEventTime = ie.getWhen();
1240 }
1241 } else if (e instanceof InputMethodEvent) {
1242 InputMethodEvent ime = (InputMethodEvent)e;
1243 mostRecentEventTime2 = ime.getWhen();
1244 } else if (e instanceof ActionEvent) {
1245 ActionEvent ae = (ActionEvent)e;
1246 mostRecentEventTime2 = ae.getWhen();
1247 } else if (e instanceof InvocationEvent) {
1248 InvocationEvent ie = (InvocationEvent)e;
1249 mostRecentEventTime2 = ie.getWhen();
1250 }
1251 mostRecentEventTime = Math.max(mostRecentEventTime, mostRecentEventTime2);
1252 } finally {
1253 pushPopLock.unlock();
1254 }
1255 }
1256
1257 /**
1258 * Causes {@code runnable} to have its {@code run}
1259 * method called in the {@link #isDispatchThread dispatch thread} of
1260 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1261 * This will happen after all pending events are processed.
1262 *
1263 * @param runnable the {@code Runnable} whose {@code run}
1264 * method should be executed
1265 * asynchronously in the
1266 * {@link #isDispatchThread event dispatch thread}
1267 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1268 * @see #invokeAndWait
1269 * @see Toolkit#getSystemEventQueue
1270 * @see #isDispatchThread
1271 * @since 1.2
1272 */
1273 public static void invokeLater(Runnable runnable) {
1274 Toolkit.getEventQueue().postEvent(
1275 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
1276 }
1277
1278 /**
1279 * Causes {@code runnable} to have its {@code run}
1280 * method called in the {@link #isDispatchThread dispatch thread} of
1281 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1282 * This will happen after all pending events are processed.
1283 * The call blocks until this has happened. This method
1284 * will throw an Error if called from the
1285 * {@link #isDispatchThread event dispatcher thread}.
1286 *
1287 * @param runnable the {@code Runnable} whose {@code run}
1288 * method should be executed
1289 * synchronously in the
1290 * {@link #isDispatchThread event dispatch thread}
1291 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1292 * @exception InterruptedException if any thread has
1293 * interrupted this thread
1294 * @exception InvocationTargetException if an throwable is thrown
1295 * when running {@code runnable}
1296 * @see #invokeLater
1297 * @see Toolkit#getSystemEventQueue
1298 * @see #isDispatchThread
1299 * @since 1.2
1300 */
1301 public static void invokeAndWait(Runnable runnable)
1302 throws InterruptedException, InvocationTargetException
1303 {
1304 invokeAndWait(Toolkit.getDefaultToolkit(), runnable);
1305 }
1306
1307 static void invokeAndWait(Object source, Runnable runnable)
1308 throws InterruptedException, InvocationTargetException
1309 {
1310 if (EventQueue.isDispatchThread()) {
1311 throw new Error("Cannot call invokeAndWait from the event dispatcher thread");
1312 }
1313
1314 class AWTInvocationLock {}
1315 Object lock = new AWTInvocationLock();
1316
1317 InvocationEvent event =
1318 new InvocationEvent(source, runnable, lock, true);
1319
1320 synchronized (lock) {
1321 Toolkit.getEventQueue().postEvent(event);
1322 while (!event.isDispatched()) {
1323 lock.wait();
1324 }
1325 }
1326
1327 Throwable eventThrowable = event.getThrowable();
1328 if (eventThrowable != null) {
1329 throw new InvocationTargetException(eventThrowable);
1330 }
1331 }
1332
1333 /*
1334 * Called from PostEventQueue.postEvent to notify that a new event
1335 * appeared. First it proceeds to the EventQueue on the top of the
1336 * stack, then notifies the associated dispatch thread if it exists
1337 * or starts a new one otherwise.
1338 */
1339 private void wakeup(boolean isShutdown) {
1340 pushPopLock.lock();
1341 try {
1342 if (nextQueue != null) {
1343 // Forward call to the top of EventQueue stack.
1344 nextQueue.wakeup(isShutdown);
1345 } else if (dispatchThread != null) {
1346 pushPopCond.signalAll();
1347 } else if (!isShutdown) {
1348 initDispatchThread();
1349 }
1350 } finally {
1351 pushPopLock.unlock();
1352 }
1353 }
1354
1355 // The method is used by AWTAccessor for javafx/AWT single threaded mode.
1356 private void setFwDispatcher(FwDispatcher dispatcher) {
1357 if (nextQueue != null) {
1358 nextQueue.setFwDispatcher(dispatcher);
1359 } else {
1360 fwDispatcher = dispatcher;
1361 }
1362 }
1363 }
1364
1365 /**
1366 * The Queue object holds pointers to the beginning and end of one internal
1367 * queue. An EventQueue object is composed of multiple internal Queues, one
1368 * for each priority supported by the EventQueue. All Events on a particular
1369 * internal Queue have identical priority.
1370 */
1371 class Queue {
1372 EventQueueItem head;
1373 EventQueueItem tail;
1374 }