1 /*
2 * Copyright (c) 1996, 2014, 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</code> 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</code> 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</code> 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</code> A is enqueued
73 * to the <code>EventQueue</code> before
74 * <code>AWTEvent</code> 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</code>
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</code> 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 final static 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</code>.
255 * If there is an existing event on the queue with the same ID
256 * and event source, the source <code>Component</code>'s
257 * <code>coalesceEvents</code> method will be called.
258 *
259 * @param theEvent an instance of <code>java.awt.AWTEvent</code>,
260 * or a subclass of it
261 * @throws NullPointerException if <code>theEvent</code> is <code>null</code>
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</code>.
270 * If there is an existing event on the queue with the same ID
271 * and event source, the source <code>Component</code>'s
272 * <code>coalesceEvents</code> method will be called.
273 *
274 * @param theEvent an instance of <code>java.awt.AWTEvent</code>,
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</code>,
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</code> and
536 * returns it. This method will block until an event has
537 * been posted by another thread.
538 * @return the next <code>AWTEvent</code>
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</code>
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</code>
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 border=1 summary="Event types, source types, and dispatch methods">
672 * <tr>
673 * <th>Event Type</th>
674 * <th>Source Type</th>
675 * <th>Dispatched To</th>
676 * </tr>
677 * <tr>
678 * <td>ActiveEvent</td>
679 * <td>Any</td>
680 * <td>event.dispatch()</td>
681 * </tr>
682 * <tr>
683 * <td>Other</td>
684 * <td>Component</td>
685 * <td>source.dispatchEvent(AWTEvent)</td>
686 * </tr>
687 * <tr>
688 * <td>Other</td>
689 * <td>MenuComponent</td>
690 * <td>source.dispatchEvent(AWTEvent)</td>
691 * </tr>
692 * <tr>
693 * <td>Other</td>
694 * <td>Other</td>
695 * <td>No action (ignored)</td>
696 * </tr>
697 * </table>
698 *
699 * @param event an instance of <code>java.awt.AWTEvent</code>,
700 * or a subclass of it
701 * @throws NullPointerException if <code>event</code> is <code>null</code>
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 dispatchEventImpl(event, src);
718 }
719 });
720 }
721 return null;
722 }
723 };
724
725 final AccessControlContext stack = AccessController.getContext();
726 final AccessControlContext srcAcc = getAccessControlContextFrom(src);
727 final AccessControlContext eventAcc = event.getAccessControlContext();
728 if (srcAcc == null) {
729 javaSecurityAccess.doIntersectionPrivilege(action, stack, eventAcc);
730 } else {
731 javaSecurityAccess.doIntersectionPrivilege(
732 new PrivilegedAction<Void>() {
733 public Void run() {
734 javaSecurityAccess.doIntersectionPrivilege(action, eventAcc);
735 return null;
736 }
737 }, stack, srcAcc);
738 }
739 }
740
741 private static AccessControlContext getAccessControlContextFrom(Object src) {
742 return src instanceof Component ?
743 ((Component)src).getAccessControlContext() :
744 src instanceof MenuComponent ?
745 ((MenuComponent)src).getAccessControlContext() :
746 src instanceof TrayIcon ?
747 ((TrayIcon)src).getAccessControlContext() :
748 null;
749 }
750
751 /**
752 * Called from dispatchEvent() under a correct AccessControlContext
753 */
754 private void dispatchEventImpl(final AWTEvent event, final Object src) {
755 event.isPosted = true;
756 if (event instanceof ActiveEvent) {
757 // This could become the sole method of dispatching in time.
758 setCurrentEventAndMostRecentTimeImpl(event);
759 ((ActiveEvent)event).dispatch();
760 } else if (src instanceof Component) {
761 ((Component)src).dispatchEvent(event);
762 event.dispatched();
763 } else if (src instanceof MenuComponent) {
764 ((MenuComponent)src).dispatchEvent(event);
765 } else if (src instanceof TrayIcon) {
766 ((TrayIcon)src).dispatchEvent(event);
767 } else if (src instanceof AWTAutoShutdown) {
768 if (noEvents()) {
769 dispatchThread.stopDispatching();
770 }
771 } else {
772 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
773 getEventLog().fine("Unable to dispatch event: " + event);
774 }
775 }
776 }
777
778 /**
779 * Returns the timestamp of the most recent event that had a timestamp, and
780 * that was dispatched from the <code>EventQueue</code> associated with the
781 * calling thread. If an event with a timestamp is currently being
782 * dispatched, its timestamp will be returned. If no events have yet
783 * been dispatched, the EventQueue's initialization time will be
784 * returned instead.In the current version of
785 * the JDK, only <code>InputEvent</code>s,
786 * <code>ActionEvent</code>s, and <code>InvocationEvent</code>s have
787 * timestamps; however, future versions of the JDK may add timestamps to
788 * additional event types. Note that this method should only be invoked
789 * from an application's {@link #isDispatchThread event dispatching thread}.
790 * If this method is
791 * invoked from another thread, the current system time (as reported by
792 * <code>System.currentTimeMillis()</code>) will be returned instead.
793 *
794 * @return the timestamp of the last <code>InputEvent</code>,
795 * <code>ActionEvent</code>, or <code>InvocationEvent</code> to be
796 * dispatched, or <code>System.currentTimeMillis()</code> if this
797 * method is invoked on a thread other than an event dispatching
798 * thread
799 * @see java.awt.event.InputEvent#getWhen
800 * @see java.awt.event.ActionEvent#getWhen
801 * @see java.awt.event.InvocationEvent#getWhen
802 * @see #isDispatchThread
803 *
804 * @since 1.4
805 */
806 public static long getMostRecentEventTime() {
807 return Toolkit.getEventQueue().getMostRecentEventTimeImpl();
808 }
809 private long getMostRecentEventTimeImpl() {
810 pushPopLock.lock();
811 try {
812 return (Thread.currentThread() == dispatchThread)
813 ? mostRecentEventTime
814 : System.currentTimeMillis();
815 } finally {
816 pushPopLock.unlock();
817 }
818 }
819
820 /**
821 * @return most recent event time on all threads.
822 */
823 long getMostRecentEventTimeEx() {
824 pushPopLock.lock();
825 try {
826 return mostRecentEventTime;
827 } finally {
828 pushPopLock.unlock();
829 }
830 }
831
832 /**
833 * Returns the event currently being dispatched by the
834 * <code>EventQueue</code> associated with the calling thread. This is
835 * useful if a method needs access to the event, but was not designed to
836 * receive a reference to it as an argument. Note that this method should
837 * only be invoked from an application's event dispatching thread. If this
838 * method is invoked from another thread, null will be returned.
839 *
840 * @return the event currently being dispatched, or null if this method is
841 * invoked on a thread other than an event dispatching thread
842 * @since 1.4
843 */
844 public static AWTEvent getCurrentEvent() {
845 return Toolkit.getEventQueue().getCurrentEventImpl();
846 }
847 private AWTEvent getCurrentEventImpl() {
848 pushPopLock.lock();
849 try {
850 return (Thread.currentThread() == dispatchThread)
851 ? currentEvent.get()
852 : null;
853 } finally {
854 pushPopLock.unlock();
855 }
856 }
857
858 /**
859 * Replaces the existing <code>EventQueue</code> with the specified one.
860 * Any pending events are transferred to the new <code>EventQueue</code>
861 * for processing by it.
862 *
863 * @param newEventQueue an <code>EventQueue</code>
864 * (or subclass thereof) instance to be use
865 * @see java.awt.EventQueue#pop
866 * @throws NullPointerException if <code>newEventQueue</code> is <code>null</code>
867 * @since 1.2
868 */
869 public void push(EventQueue newEventQueue) {
870 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
871 getEventLog().fine("EventQueue.push(" + newEventQueue + ")");
872 }
873
874 pushPopLock.lock();
875 try {
876 EventQueue topQueue = this;
877 while (topQueue.nextQueue != null) {
878 topQueue = topQueue.nextQueue;
879 }
880 if (topQueue.fwDispatcher != null) {
881 throw new RuntimeException("push() to queue with fwDispatcher");
882 }
883 if ((topQueue.dispatchThread != null) &&
884 (topQueue.dispatchThread.getEventQueue() == this))
885 {
886 newEventQueue.dispatchThread = topQueue.dispatchThread;
887 topQueue.dispatchThread.setEventQueue(newEventQueue);
888 }
889
890 // Transfer all events forward to new EventQueue.
891 while (topQueue.peekEvent() != null) {
892 try {
893 // Use getNextEventPrivate() as it doesn't call flushPendingEvents()
894 newEventQueue.postEventPrivate(topQueue.getNextEventPrivate());
895 } catch (InterruptedException ie) {
896 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
897 getEventLog().fine("Interrupted push", ie);
898 }
899 }
900 }
901
902 // Wake up EDT waiting in getNextEvent(), so it can
903 // pick up a new EventQueue. Post the waking event before
904 // topQueue.nextQueue is assigned, otherwise the event would
905 // go newEventQueue
906 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
907
908 newEventQueue.previousQueue = topQueue;
909 topQueue.nextQueue = newEventQueue;
910
911 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == topQueue) {
912 appContext.put(AppContext.EVENT_QUEUE_KEY, newEventQueue);
913 }
914
915 pushPopCond.signalAll();
916 } finally {
917 pushPopLock.unlock();
918 }
919 }
920
921 /**
922 * Stops dispatching events using this <code>EventQueue</code>.
923 * Any pending events are transferred to the previous
924 * <code>EventQueue</code> for processing.
925 * <p>
926 * Warning: To avoid deadlock, do not declare this method
927 * synchronized in a subclass.
928 *
929 * @exception EmptyStackException if no previous push was made
930 * on this <code>EventQueue</code>
931 * @see java.awt.EventQueue#push
932 * @since 1.2
933 */
934 protected void pop() throws EmptyStackException {
935 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
936 getEventLog().fine("EventQueue.pop(" + this + ")");
937 }
938
939 pushPopLock.lock();
940 try {
941 EventQueue topQueue = this;
942 while (topQueue.nextQueue != null) {
943 topQueue = topQueue.nextQueue;
944 }
945 EventQueue prevQueue = topQueue.previousQueue;
946 if (prevQueue == null) {
947 throw new EmptyStackException();
948 }
949
950 topQueue.previousQueue = null;
951 prevQueue.nextQueue = null;
952
953 // Transfer all events back to previous EventQueue.
954 while (topQueue.peekEvent() != null) {
955 try {
956 prevQueue.postEventPrivate(topQueue.getNextEventPrivate());
957 } catch (InterruptedException ie) {
958 if (getEventLog().isLoggable(PlatformLogger.Level.FINE)) {
959 getEventLog().fine("Interrupted pop", ie);
960 }
961 }
962 }
963
964 if ((topQueue.dispatchThread != null) &&
965 (topQueue.dispatchThread.getEventQueue() == this))
966 {
967 prevQueue.dispatchThread = topQueue.dispatchThread;
968 topQueue.dispatchThread.setEventQueue(prevQueue);
969 }
970
971 if (appContext.get(AppContext.EVENT_QUEUE_KEY) == this) {
972 appContext.put(AppContext.EVENT_QUEUE_KEY, prevQueue);
973 }
974
975 // Wake up EDT waiting in getNextEvent(), so it can
976 // pick up a new EventQueue
977 topQueue.postEventPrivate(new InvocationEvent(topQueue, dummyRunnable));
978
979 pushPopCond.signalAll();
980 } finally {
981 pushPopLock.unlock();
982 }
983 }
984
985 /**
986 * Creates a new {@code secondary loop} associated with this
987 * event queue. Use the {@link SecondaryLoop#enter} and
988 * {@link SecondaryLoop#exit} methods to start and stop the
989 * event loop and dispatch the events from this queue.
990 *
991 * @return secondaryLoop A new secondary loop object, which can
992 * be used to launch a new nested event
993 * loop and dispatch events from this queue
994 *
995 * @see SecondaryLoop#enter
996 * @see SecondaryLoop#exit
997 *
998 * @since 1.7
999 */
1000 public SecondaryLoop createSecondaryLoop() {
1001 return createSecondaryLoop(null, null, 0);
1002 }
1003
1004 SecondaryLoop createSecondaryLoop(Conditional cond, EventFilter filter, long interval) {
1005 pushPopLock.lock();
1006 try {
1007 if (nextQueue != null) {
1008 // Forward the request to the top of EventQueue stack
1009 return nextQueue.createSecondaryLoop(cond, filter, interval);
1010 }
1011 if (fwDispatcher != null) {
1012 return fwDispatcher.createSecondaryLoop();
1013 }
1014 if (dispatchThread == null) {
1015 initDispatchThread();
1016 }
1017 return new WaitDispatchSupport(dispatchThread, cond, filter, interval);
1018 } finally {
1019 pushPopLock.unlock();
1020 }
1021 }
1022
1023 /**
1024 * Returns true if the calling thread is
1025 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1026 * dispatch thread. Use this method to ensure that a particular
1027 * task is being executed (or not being) there.
1028 * <p>
1029 * Note: use the {@link #invokeLater} or {@link #invokeAndWait}
1030 * methods to execute a task in
1031 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1032 * dispatch thread.
1033 *
1034 * @return true if running in
1035 * {@link Toolkit#getSystemEventQueue the current AWT EventQueue}'s
1036 * dispatch thread
1037 * @see #invokeLater
1038 * @see #invokeAndWait
1039 * @see Toolkit#getSystemEventQueue
1040 * @since 1.2
1041 */
1042 public static boolean isDispatchThread() {
1043 EventQueue eq = Toolkit.getEventQueue();
1044 return eq.isDispatchThreadImpl();
1045 }
1046
1047 final boolean isDispatchThreadImpl() {
1048 EventQueue eq = this;
1049 pushPopLock.lock();
1050 try {
1051 EventQueue next = eq.nextQueue;
1052 while (next != null) {
1053 eq = next;
1054 next = eq.nextQueue;
1055 }
1056 if (eq.fwDispatcher != null) {
1057 return eq.fwDispatcher.isDispatchThread();
1058 }
1059 return (Thread.currentThread() == eq.dispatchThread);
1060 } finally {
1061 pushPopLock.unlock();
1062 }
1063 }
1064
1065 final void initDispatchThread() {
1066 pushPopLock.lock();
1067 try {
1068 if (dispatchThread == null && !threadGroup.isDestroyed() && !appContext.isDisposed()) {
1069 dispatchThread = AccessController.doPrivileged(
1070 new PrivilegedAction<EventDispatchThread>() {
1071 public EventDispatchThread run() {
1072 EventDispatchThread t =
1073 new EventDispatchThread(threadGroup,
1074 name,
1075 EventQueue.this);
1076 t.setContextClassLoader(classLoader);
1077 t.setPriority(Thread.NORM_PRIORITY + 1);
1078 t.setDaemon(false);
1079 AWTAutoShutdown.getInstance().notifyThreadBusy(t);
1080 return t;
1081 }
1082 }
1083 );
1084 dispatchThread.start();
1085 }
1086 } finally {
1087 pushPopLock.unlock();
1088 }
1089 }
1090
1091 final void detachDispatchThread(EventDispatchThread edt) {
1092 /*
1093 * Minimize discard possibility for non-posted events
1094 */
1095 SunToolkit.flushPendingEvents(appContext);
1096 /*
1097 * This synchronized block is to secure that the event dispatch
1098 * thread won't die in the middle of posting a new event to the
1099 * associated event queue. It is important because we notify
1100 * that the event dispatch thread is busy after posting a new event
1101 * to its queue, so the EventQueue.dispatchThread reference must
1102 * be valid at that point.
1103 */
1104 pushPopLock.lock();
1105 try {
1106 if (edt == dispatchThread) {
1107 dispatchThread = null;
1108 }
1109 AWTAutoShutdown.getInstance().notifyThreadFree(edt);
1110 /*
1111 * Event was posted after EDT events pumping had stopped, so start
1112 * another EDT to handle this event
1113 */
1114 if (peekEvent() != null) {
1115 initDispatchThread();
1116 }
1117 } finally {
1118 pushPopLock.unlock();
1119 }
1120 }
1121
1122 /*
1123 * Gets the <code>EventDispatchThread</code> for this
1124 * <code>EventQueue</code>.
1125 * @return the event dispatch thread associated with this event queue
1126 * or <code>null</code> if this event queue doesn't have a
1127 * working thread associated with it
1128 * @see java.awt.EventQueue#initDispatchThread
1129 * @see java.awt.EventQueue#detachDispatchThread
1130 */
1131 final EventDispatchThread getDispatchThread() {
1132 pushPopLock.lock();
1133 try {
1134 return dispatchThread;
1135 } finally {
1136 pushPopLock.unlock();
1137 }
1138 }
1139
1140 /*
1141 * Removes any pending events for the specified source object.
1142 * If removeAllEvents parameter is <code>true</code> then all
1143 * events for the specified source object are removed, if it
1144 * is <code>false</code> then <code>SequencedEvent</code>, <code>SentEvent</code>,
1145 * <code>FocusEvent</code>, <code>WindowEvent</code>, <code>KeyEvent</code>,
1146 * and <code>InputMethodEvent</code> are kept in the queue, but all other
1147 * events are removed.
1148 *
1149 * This method is normally called by the source's
1150 * <code>removeNotify</code> method.
1151 */
1152 final void removeSourceEvents(Object source, boolean removeAllEvents) {
1153 SunToolkit.flushPendingEvents(appContext);
1154 pushPopLock.lock();
1155 try {
1156 for (int i = 0; i < NUM_PRIORITIES; i++) {
1157 EventQueueItem entry = queues[i].head;
1158 EventQueueItem prev = null;
1159 while (entry != null) {
1160 if ((entry.event.getSource() == source)
1161 && (removeAllEvents
1162 || ! (entry.event instanceof SequencedEvent
1163 || entry.event instanceof SentEvent
1164 || entry.event instanceof FocusEvent
1165 || entry.event instanceof WindowEvent
1166 || entry.event instanceof KeyEvent
1167 || entry.event instanceof InputMethodEvent)))
1168 {
1169 if (entry.event instanceof SequencedEvent) {
1170 ((SequencedEvent)entry.event).dispose();
1171 }
1172 if (entry.event instanceof SentEvent) {
1173 ((SentEvent)entry.event).dispose();
1174 }
1175 if (entry.event instanceof InvocationEvent) {
1176 AWTAccessor.getInvocationEventAccessor()
1177 .dispose((InvocationEvent)entry.event);
1178 }
1179 if (prev == null) {
1180 queues[i].head = entry.next;
1181 } else {
1182 prev.next = entry.next;
1183 }
1184 uncacheEQItem(entry);
1185 } else {
1186 prev = entry;
1187 }
1188 entry = entry.next;
1189 }
1190 queues[i].tail = prev;
1191 }
1192 } finally {
1193 pushPopLock.unlock();
1194 }
1195 }
1196
1197 synchronized long getMostRecentKeyEventTime() {
1198 pushPopLock.lock();
1199 try {
1200 return mostRecentKeyEventTime;
1201 } finally {
1202 pushPopLock.unlock();
1203 }
1204 }
1205
1206 static void setCurrentEventAndMostRecentTime(AWTEvent e) {
1207 Toolkit.getEventQueue().setCurrentEventAndMostRecentTimeImpl(e);
1208 }
1209 private void setCurrentEventAndMostRecentTimeImpl(AWTEvent e) {
1210 pushPopLock.lock();
1211 try {
1212 if (Thread.currentThread() != dispatchThread) {
1213 return;
1214 }
1215
1216 currentEvent = new WeakReference<>(e);
1217
1218 // This series of 'instanceof' checks should be replaced with a
1219 // polymorphic type (for example, an interface which declares a
1220 // getWhen() method). However, this would require us to make such
1221 // a type public, or to place it in sun.awt. Both of these approaches
1222 // have been frowned upon. So for now, we hack.
1223 //
1224 // In tiger, we will probably give timestamps to all events, so this
1225 // will no longer be an issue.
1226 long mostRecentEventTime2 = Long.MIN_VALUE;
1227 if (e instanceof InputEvent) {
1228 InputEvent ie = (InputEvent)e;
1229 mostRecentEventTime2 = ie.getWhen();
1230 if (e instanceof KeyEvent) {
1231 mostRecentKeyEventTime = ie.getWhen();
1232 }
1233 } else if (e instanceof InputMethodEvent) {
1234 InputMethodEvent ime = (InputMethodEvent)e;
1235 mostRecentEventTime2 = ime.getWhen();
1236 } else if (e instanceof ActionEvent) {
1237 ActionEvent ae = (ActionEvent)e;
1238 mostRecentEventTime2 = ae.getWhen();
1239 } else if (e instanceof InvocationEvent) {
1240 InvocationEvent ie = (InvocationEvent)e;
1241 mostRecentEventTime2 = ie.getWhen();
1242 }
1243 mostRecentEventTime = Math.max(mostRecentEventTime, mostRecentEventTime2);
1244 } finally {
1245 pushPopLock.unlock();
1246 }
1247 }
1248
1249 /**
1250 * Causes <code>runnable</code> to have its <code>run</code>
1251 * method called in the {@link #isDispatchThread dispatch thread} of
1252 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1253 * This will happen after all pending events are processed.
1254 *
1255 * @param runnable the <code>Runnable</code> whose <code>run</code>
1256 * method should be executed
1257 * asynchronously in the
1258 * {@link #isDispatchThread event dispatch thread}
1259 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1260 * @see #invokeAndWait
1261 * @see Toolkit#getSystemEventQueue
1262 * @see #isDispatchThread
1263 * @since 1.2
1264 */
1265 public static void invokeLater(Runnable runnable) {
1266 Toolkit.getEventQueue().postEvent(
1267 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
1268 }
1269
1270 /**
1271 * Causes <code>runnable</code> to have its <code>run</code>
1272 * method called in the {@link #isDispatchThread dispatch thread} of
1273 * {@link Toolkit#getSystemEventQueue the system EventQueue}.
1274 * This will happen after all pending events are processed.
1275 * The call blocks until this has happened. This method
1276 * will throw an Error if called from the
1277 * {@link #isDispatchThread event dispatcher thread}.
1278 *
1279 * @param runnable the <code>Runnable</code> whose <code>run</code>
1280 * method should be executed
1281 * synchronously in the
1282 * {@link #isDispatchThread event dispatch thread}
1283 * of {@link Toolkit#getSystemEventQueue the system EventQueue}
1284 * @exception InterruptedException if any thread has
1285 * interrupted this thread
1286 * @exception InvocationTargetException if an throwable is thrown
1287 * when running <code>runnable</code>
1288 * @see #invokeLater
1289 * @see Toolkit#getSystemEventQueue
1290 * @see #isDispatchThread
1291 * @since 1.2
1292 */
1293 public static void invokeAndWait(Runnable runnable)
1294 throws InterruptedException, InvocationTargetException
1295 {
1296 invokeAndWait(Toolkit.getDefaultToolkit(), runnable);
1297 }
1298
1299 static void invokeAndWait(Object source, Runnable runnable)
1300 throws InterruptedException, InvocationTargetException
1301 {
1302 if (EventQueue.isDispatchThread()) {
1303 throw new Error("Cannot call invokeAndWait from the event dispatcher thread");
1304 }
1305
1306 class AWTInvocationLock {}
1307 Object lock = new AWTInvocationLock();
1308
1309 InvocationEvent event =
1310 new InvocationEvent(source, runnable, lock, true);
1311
1312 synchronized (lock) {
1313 Toolkit.getEventQueue().postEvent(event);
1314 while (!event.isDispatched()) {
1315 lock.wait();
1316 }
1317 }
1318
1319 Throwable eventThrowable = event.getThrowable();
1320 if (eventThrowable != null) {
1321 throw new InvocationTargetException(eventThrowable);
1322 }
1323 }
1324
1325 /*
1326 * Called from PostEventQueue.postEvent to notify that a new event
1327 * appeared. First it proceeds to the EventQueue on the top of the
1328 * stack, then notifies the associated dispatch thread if it exists
1329 * or starts a new one otherwise.
1330 */
1331 private void wakeup(boolean isShutdown) {
1332 pushPopLock.lock();
1333 try {
1334 if (nextQueue != null) {
1335 // Forward call to the top of EventQueue stack.
1336 nextQueue.wakeup(isShutdown);
1337 } else if (dispatchThread != null) {
1338 pushPopCond.signalAll();
1339 } else if (!isShutdown) {
1340 initDispatchThread();
1341 }
1342 } finally {
1343 pushPopLock.unlock();
1344 }
1345 }
1346
1347 // The method is used by AWTAccessor for javafx/AWT single threaded mode.
1348 private void setFwDispatcher(FwDispatcher dispatcher) {
1349 if (nextQueue != null) {
1350 nextQueue.setFwDispatcher(dispatcher);
1351 } else {
1352 fwDispatcher = dispatcher;
1353 }
1354 }
1355 }
1356
1357 /**
1358 * The Queue object holds pointers to the beginning and end of one internal
1359 * queue. An EventQueue object is composed of multiple internal Queues, one
1360 * for each priority supported by the EventQueue. All Events on a particular
1361 * internal Queue have identical priority.
1362 */
1363 class Queue {
1364 EventQueueItem head;
1365 EventQueueItem tail;
1366 }