1 /*
2 * Copyright (c) 1998, 2008, 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 sun.awt;
27
28 import java.awt.EventQueue;
29 import java.awt.Window;
30 import java.awt.SystemTray;
31 import java.awt.TrayIcon;
32 import java.awt.Toolkit;
33 import java.awt.GraphicsEnvironment;
34 import java.awt.event.InvocationEvent;
35 import java.security.AccessController;
36 import java.security.PrivilegedAction;
37 import java.util.Collections;
38 import java.util.HashMap;
39 import java.util.IdentityHashMap;
40 import java.util.Map;
41 import java.util.Set;
42 import java.util.HashSet;
43 import java.beans.PropertyChangeSupport;
44 import java.beans.PropertyChangeListener;
45 import sun.util.logging.PlatformLogger;
46 import java.util.concurrent.locks.Condition;
47 import java.util.concurrent.locks.Lock;
48 import java.util.concurrent.locks.ReentrantLock;
49 import java.util.concurrent.atomic.AtomicInteger;
50
51 /**
52 * The AppContext is a table referenced by ThreadGroup which stores
53 * application service instances. (If you are not writing an application
54 * service, or don't know what one is, please do not use this class.)
55 * The AppContext allows applet access to what would otherwise be
56 * potentially dangerous services, such as the ability to peek at
57 * EventQueues or change the look-and-feel of a Swing application.<p>
58 *
59 * Most application services use a singleton object to provide their
60 * services, either as a default (such as getSystemEventQueue or
61 * getDefaultToolkit) or as static methods with class data (System).
62 * The AppContext works with the former method by extending the concept
63 * of "default" to be ThreadGroup-specific. Application services
64 * lookup their singleton in the AppContext.<p>
65 *
66 * For example, here we have a Foo service, with its pre-AppContext
67 * code:<p>
68 * <code><pre>
69 * public class Foo {
70 * private static Foo defaultFoo = new Foo();
71 *
72 * public static Foo getDefaultFoo() {
73 * return defaultFoo;
74 * }
75 *
76 * ... Foo service methods
77 * }</pre></code><p>
78 *
79 * The problem with the above is that the Foo service is global in scope,
80 * so that applets and other untrusted code can execute methods on the
81 * single, shared Foo instance. The Foo service therefore either needs
82 * to block its use by untrusted code using a SecurityManager test, or
83 * restrict its capabilities so that it doesn't matter if untrusted code
84 * executes it.<p>
85 *
86 * Here's the Foo class written to use the AppContext:<p>
87 * <code><pre>
88 * public class Foo {
89 * public static Foo getDefaultFoo() {
90 * Foo foo = (Foo)AppContext.getAppContext().get(Foo.class);
91 * if (foo == null) {
92 * foo = new Foo();
93 * getAppContext().put(Foo.class, foo);
94 * }
95 * return foo;
96 * }
97 *
98 * ... Foo service methods
99 * }</pre></code><p>
100 *
101 * Since a separate AppContext can exist for each ThreadGroup, trusted
102 * and untrusted code have access to different Foo instances. This allows
103 * untrusted code access to "system-wide" services -- the service remains
104 * within the AppContext "sandbox". For example, say a malicious applet
105 * wants to peek all of the key events on the EventQueue to listen for
106 * passwords; if separate EventQueues are used for each ThreadGroup
107 * using AppContexts, the only key events that applet will be able to
108 * listen to are its own. A more reasonable applet request would be to
109 * change the Swing default look-and-feel; with that default stored in
110 * an AppContext, the applet's look-and-feel will change without
111 * disrupting other applets or potentially the browser itself.<p>
112 *
113 * Because the AppContext is a facility for safely extending application
114 * service support to applets, none of its methods may be blocked by a
115 * a SecurityManager check in a valid Java implementation. Applets may
116 * therefore safely invoke any of its methods without worry of being
117 * blocked.
118 *
119 * Note: If a SecurityManager is installed which derives from
120 * sun.awt.AWTSecurityManager, it may override the
121 * AWTSecurityManager.getAppContext() method to return the proper
122 * AppContext based on the execution context, in the case where
123 * the default ThreadGroup-based AppContext indexing would return
124 * the main "system" AppContext. For example, in an applet situation,
125 * if a system thread calls into an applet, rather than returning the
126 * main "system" AppContext (the one corresponding to the system thread),
127 * an installed AWTSecurityManager may return the applet's AppContext
128 * based on the execution context.
129 *
130 * @author Thomas Ball
131 * @author Fred Ecks
132 */
133 public final class AppContext {
134 private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.AppContext");
135
136 /* Since the contents of an AppContext are unique to each Java
137 * session, this class should never be serialized. */
138
139 /*
140 * The key to put()/get() the Java EventQueue into/from the AppContext.
141 */
142 public static final Object EVENT_QUEUE_KEY = new StringBuffer("EventQueue");
143
144 /*
145 * The keys to store EventQueue push/pop lock and condition.
146 */
147 public final static Object EVENT_QUEUE_LOCK_KEY = new StringBuilder("EventQueue.Lock");
148 public final static Object EVENT_QUEUE_COND_KEY = new StringBuilder("EventQueue.Condition");
149
150 /* A map of AppContexts, referenced by ThreadGroup.
151 */
152 private static final Map<ThreadGroup, AppContext> threadGroup2appContext =
153 Collections.synchronizedMap(new IdentityHashMap<ThreadGroup, AppContext>());
154
155 /**
156 * Returns a set containing all <code>AppContext</code>s.
157 */
158 public static Set<AppContext> getAppContexts() {
159 synchronized (threadGroup2appContext) {
160 return new HashSet<AppContext>(threadGroup2appContext.values());
161 }
162 }
163
164 /* The main "system" AppContext, used by everything not otherwise
165 contained in another AppContext. It is implicitly created for
166 standalone apps only (i.e. not applets)
167 */
168 private static volatile AppContext mainAppContext = null;
169
170 private static class GetAppContextLock {};
171 private final static Object getAppContextLock = new GetAppContextLock();
172
173 /*
174 * The hash map associated with this AppContext. A private delegate
175 * is used instead of subclassing HashMap so as to avoid all of
176 * HashMap's potentially risky methods, such as clear(), elements(),
177 * putAll(), etc.
178 */
179 private final Map<Object, Object> table = new HashMap<>();
180
181 private final ThreadGroup threadGroup;
182
183 /**
184 * If any <code>PropertyChangeListeners</code> have been registered,
185 * the <code>changeSupport</code> field describes them.
186 *
187 * @see #addPropertyChangeListener
188 * @see #removePropertyChangeListener
189 * @see #firePropertyChange
190 */
191 private PropertyChangeSupport changeSupport = null;
192
193 public static final String DISPOSED_PROPERTY_NAME = "disposed";
194 public static final String GUI_DISPOSED = "guidisposed";
195
196 private enum State {
197 VALID,
198 BEING_DISPOSED,
199 DISPOSED
200 };
201
202 private volatile State state = State.VALID;
203
204 public boolean isDisposed() {
205 return state == State.DISPOSED;
206 }
207
208 /*
209 * The total number of AppContexts, system-wide. This number is
210 * incremented at the beginning of the constructor, and decremented
211 * at the end of dispose(). getAppContext() checks to see if this
212 * number is 1. If so, it returns the sole AppContext without
213 * checking Thread.currentThread().
214 */
215 private static final AtomicInteger numAppContexts = new AtomicInteger(0);
216
217
218 /*
219 * The context ClassLoader that was used to create this AppContext.
220 */
221 private final ClassLoader contextClassLoader;
222
223 /**
224 * Constructor for AppContext. This method is <i>not</i> public,
225 * nor should it ever be used as such. The proper way to construct
226 * an AppContext is through the use of SunToolkit.createNewAppContext.
227 * A ThreadGroup is created for the new AppContext, a Thread is
228 * created within that ThreadGroup, and that Thread calls
229 * SunToolkit.createNewAppContext before calling anything else.
230 * That creates both the new AppContext and its EventQueue.
231 *
232 * @param threadGroup The ThreadGroup for the new AppContext
233 * @see sun.awt.SunToolkit
234 * @since 1.2
235 */
236 AppContext(ThreadGroup threadGroup) {
237 numAppContexts.incrementAndGet();
238
239 this.threadGroup = threadGroup;
240 threadGroup2appContext.put(threadGroup, this);
241
242 this.contextClassLoader =
243 AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
244 public ClassLoader run() {
245 return Thread.currentThread().getContextClassLoader();
246 }
247 });
248
249 // Initialize push/pop lock and its condition to be used by all the
250 // EventQueues within this AppContext
251 Lock eventQueuePushPopLock = new ReentrantLock();
252 put(EVENT_QUEUE_LOCK_KEY, eventQueuePushPopLock);
253 Condition eventQueuePushPopCond = eventQueuePushPopLock.newCondition();
254 put(EVENT_QUEUE_COND_KEY, eventQueuePushPopCond);
255 }
256
257 private static final ThreadLocal<AppContext> threadAppContext =
258 new ThreadLocal<AppContext>();
259
260 private final static void initMainAppContext() {
261 // On the main Thread, we get the ThreadGroup, make a corresponding
262 // AppContext, and instantiate the Java EventQueue. This way, legacy
263 // code is unaffected by the move to multiple AppContext ability.
264 AccessController.doPrivileged(new PrivilegedAction<Void>() {
265 public Void run() {
266 ThreadGroup currentThreadGroup =
267 Thread.currentThread().getThreadGroup();
268 ThreadGroup parentThreadGroup = currentThreadGroup.getParent();
269 while (parentThreadGroup != null) {
270 // Find the root ThreadGroup to construct our main AppContext
271 currentThreadGroup = parentThreadGroup;
272 parentThreadGroup = currentThreadGroup.getParent();
273 }
274
275 mainAppContext = SunToolkit.createNewAppContext(currentThreadGroup);
276 return null;
277 }
278 });
279 }
280
281 /**
282 * Returns the appropriate AppContext for the caller,
283 * as determined by its ThreadGroup. If the main "system" AppContext
284 * would be returned and there's an AWTSecurityManager installed, it
285 * is called to get the proper AppContext based on the execution
286 * context.
287 *
288 * @return the AppContext for the caller.
289 * @see java.lang.ThreadGroup
290 * @since 1.2
291 */
292 public final static AppContext getAppContext() {
293 // we are standalone app, return the main app context
294 if (numAppContexts.get() == 1 && mainAppContext != null) {
295 return mainAppContext;
296 }
297
298 AppContext appContext = threadAppContext.get();
299
300 if (null == appContext) {
301 appContext = AccessController.doPrivileged(new PrivilegedAction<AppContext>()
302 {
303 public AppContext run() {
304 // Get the current ThreadGroup, and look for it and its
305 // parents in the hash from ThreadGroup to AppContext --
306 // it should be found, because we use createNewContext()
307 // when new AppContext objects are created.
308 ThreadGroup currentThreadGroup = Thread.currentThread().getThreadGroup();
309 ThreadGroup threadGroup = currentThreadGroup;
310
311 // Special case: we implicitly create the main app context
312 // if no contexts have been created yet. This covers standalone apps
313 // and excludes applets because by the time applet starts
314 // a number of contexts have already been created by the plugin.
315 synchronized (getAppContextLock) {
316 if (numAppContexts.get() == 0) {
317 if (System.getProperty("javaplugin.version") == null &&
318 System.getProperty("javawebstart.version") == null) {
319 initMainAppContext();
320 } else if (System.getProperty("javafx.version") != null &&
321 threadGroup.getParent() != null) {
322 // Swing inside JavaFX case
323 SunToolkit.createNewAppContext();
324 }
325 }
326 }
327
328 AppContext context = threadGroup2appContext.get(threadGroup);
329 while (context == null) {
330 threadGroup = threadGroup.getParent();
331 if (threadGroup == null) {
332 return null;
333 }
334 context = threadGroup2appContext.get(threadGroup);
335 }
336
337 // In case we did anything in the above while loop, we add
338 // all the intermediate ThreadGroups to threadGroup2appContext
339 // so we won't spin again.
340 for (ThreadGroup tg = currentThreadGroup; tg != threadGroup; tg = tg.getParent()) {
341 threadGroup2appContext.put(tg, context);
342 }
343
344 // Now we're done, so we cache the latest key/value pair.
345 threadAppContext.set(context);
346
347 return context;
348 }
349 });
350 }
351
352 return appContext;
353 }
354
355 /**
356 * Returns true if the specified AppContext is the main AppContext.
357 *
358 * @param ctx the context to compare with the main context
359 * @return true if the specified AppContext is the main AppContext.
360 * @since 1.8
361 */
362 public final static boolean isMainContext(AppContext ctx) {
363 return (ctx != null && ctx == mainAppContext);
364 }
365
366 private final static AppContext getExecutionAppContext() {
367 SecurityManager securityManager = System.getSecurityManager();
368 if ((securityManager != null) &&
369 (securityManager instanceof AWTSecurityManager))
370 {
371 AWTSecurityManager awtSecMgr = (AWTSecurityManager) securityManager;
372 AppContext secAppContext = awtSecMgr.getAppContext();
373 return secAppContext; // Return what we're told
374 }
375 return null;
376 }
377
378 private long DISPOSAL_TIMEOUT = 5000; // Default to 5-second timeout
379 // for disposal of all Frames
380 // (we wait for this time twice,
381 // once for dispose(), and once
382 // to clear the EventQueue).
383
384 private long THREAD_INTERRUPT_TIMEOUT = 1000;
385 // Default to 1-second timeout for all
386 // interrupted Threads to exit, and another
387 // 1 second for all stopped Threads to die.
388
389 /**
390 * Disposes of this AppContext, all of its top-level Frames, and
391 * all Threads and ThreadGroups contained within it.
392 *
393 * This method must be called from a Thread which is not contained
394 * within this AppContext.
395 *
396 * @exception IllegalThreadStateException if the current thread is
397 * contained within this AppContext
398 * @since 1.2
399 */
400 public void dispose() throws IllegalThreadStateException {
401 // Check to be sure that the current Thread isn't in this AppContext
402 if (this.threadGroup.parentOf(Thread.currentThread().getThreadGroup())) {
403 throw new IllegalThreadStateException(
404 "Current Thread is contained within AppContext to be disposed."
405 );
406 }
407
408 synchronized(this) {
409 if (this.state != State.VALID) {
410 return; // If already disposed or being disposed, bail.
411 }
412
413 this.state = State.BEING_DISPOSED;
414 }
415
416 final PropertyChangeSupport changeSupport = this.changeSupport;
417 if (changeSupport != null) {
418 changeSupport.firePropertyChange(DISPOSED_PROPERTY_NAME, false, true);
419 }
420
421 // First, we post an InvocationEvent to be run on the
422 // EventDispatchThread which disposes of all top-level Frames and TrayIcons
423
424 final Object notificationLock = new Object();
425
426 Runnable runnable = new Runnable() {
427 public void run() {
428 Window[] windowsToDispose = Window.getOwnerlessWindows();
429 for (Window w : windowsToDispose) {
430 try {
431 w.dispose();
432 } catch (Throwable t) {
433 log.finer("exception occured while disposing app context", t);
434 }
435 }
436 AccessController.doPrivileged(new PrivilegedAction<Void>() {
437 public Void run() {
438 if (!GraphicsEnvironment.isHeadless() && SystemTray.isSupported())
439 {
440 SystemTray systemTray = SystemTray.getSystemTray();
441 TrayIcon[] trayIconsToDispose = systemTray.getTrayIcons();
442 for (TrayIcon ti : trayIconsToDispose) {
443 systemTray.remove(ti);
444 }
445 }
446 return null;
447 }
448 });
449 // Alert PropertyChangeListeners that the GUI has been disposed.
450 if (changeSupport != null) {
451 changeSupport.firePropertyChange(GUI_DISPOSED, false, true);
452 }
453 synchronized(notificationLock) {
454 notificationLock.notifyAll(); // Notify caller that we're done
455 }
456 }
457 };
458 synchronized(notificationLock) {
459 SunToolkit.postEvent(this,
460 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
461 try {
462 notificationLock.wait(DISPOSAL_TIMEOUT);
463 } catch (InterruptedException e) { }
464 }
465
466 // Next, we post another InvocationEvent to the end of the
467 // EventQueue. When it's executed, we know we've executed all
468 // events in the queue.
469
470 runnable = new Runnable() { public void run() {
471 synchronized(notificationLock) {
472 notificationLock.notifyAll(); // Notify caller that we're done
473 }
474 } };
475 synchronized(notificationLock) {
476 SunToolkit.postEvent(this,
477 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
478 try {
479 notificationLock.wait(DISPOSAL_TIMEOUT);
480 } catch (InterruptedException e) { }
481 }
482
483 // We are done with posting events, so change the state to disposed
484 synchronized(this) {
485 this.state = State.DISPOSED;
486 }
487
488 // Next, we interrupt all Threads in the ThreadGroup
489 this.threadGroup.interrupt();
490 // Note, the EventDispatchThread we've interrupted may dump an
491 // InterruptedException to the console here. This needs to be
492 // fixed in the EventDispatchThread, not here.
493
494 // Next, we sleep 10ms at a time, waiting for all of the active
495 // Threads in the ThreadGroup to exit.
496
497 long startTime = System.currentTimeMillis();
498 long endTime = startTime + THREAD_INTERRUPT_TIMEOUT;
499 while ((this.threadGroup.activeCount() > 0) &&
500 (System.currentTimeMillis() < endTime)) {
501 try {
502 Thread.sleep(10);
503 } catch (InterruptedException e) { }
504 }
505
506 // Then, we stop any remaining Threads
507 this.threadGroup.stop();
508
509 // Next, we sleep 10ms at a time, waiting for all of the active
510 // Threads in the ThreadGroup to die.
511
512 startTime = System.currentTimeMillis();
513 endTime = startTime + THREAD_INTERRUPT_TIMEOUT;
514 while ((this.threadGroup.activeCount() > 0) &&
515 (System.currentTimeMillis() < endTime)) {
516 try {
517 Thread.sleep(10);
518 } catch (InterruptedException e) { }
519 }
520
521 // Next, we remove this and all subThreadGroups from threadGroup2appContext
522 int numSubGroups = this.threadGroup.activeGroupCount();
523 if (numSubGroups > 0) {
524 ThreadGroup [] subGroups = new ThreadGroup[numSubGroups];
525 numSubGroups = this.threadGroup.enumerate(subGroups);
526 for (int subGroup = 0; subGroup < numSubGroups; subGroup++) {
527 threadGroup2appContext.remove(subGroups[subGroup]);
528 }
529 }
530 threadGroup2appContext.remove(this.threadGroup);
531
532 threadAppContext.set(null);
533
534 // Finally, we destroy the ThreadGroup entirely.
535 try {
536 this.threadGroup.destroy();
537 } catch (IllegalThreadStateException e) {
538 // Fired if not all the Threads died, ignore it and proceed
539 }
540
541 synchronized (table) {
542 this.table.clear(); // Clear out the Hashtable to ease garbage collection
543 }
544
545 numAppContexts.decrementAndGet();
546
547 mostRecentKeyValue = null;
548 }
549
550 static final class PostShutdownEventRunnable implements Runnable {
551 private final AppContext appContext;
552
553 public PostShutdownEventRunnable(AppContext ac) {
554 appContext = ac;
555 }
556
557 public void run() {
558 final EventQueue eq = (EventQueue)appContext.get(EVENT_QUEUE_KEY);
559 if (eq != null) {
560 eq.postEvent(AWTAutoShutdown.getShutdownEvent());
561 }
562 }
563 }
564
565 static final class CreateThreadAction implements PrivilegedAction<Thread> {
566 private final AppContext appContext;
567 private final Runnable runnable;
568
569 public CreateThreadAction(AppContext ac, Runnable r) {
570 appContext = ac;
571 runnable = r;
572 }
573
574 public Thread run() {
575 Thread t = new Thread(appContext.getThreadGroup(), runnable);
576 t.setContextClassLoader(appContext.getContextClassLoader());
577 t.setPriority(Thread.NORM_PRIORITY + 1);
578 t.setDaemon(true);
579 return t;
580 }
581 }
582
583 static void stopEventDispatchThreads() {
584 for (AppContext appContext: getAppContexts()) {
585 if (appContext.isDisposed()) {
586 continue;
587 }
588 Runnable r = new PostShutdownEventRunnable(appContext);
589 // For security reasons EventQueue.postEvent should only be called
590 // on a thread that belongs to the corresponding thread group.
591 if (appContext != AppContext.getAppContext()) {
592 // Create a thread that belongs to the thread group associated
593 // with the AppContext and invokes EventQueue.postEvent.
594 PrivilegedAction<Thread> action = new CreateThreadAction(appContext, r);
595 Thread thread = AccessController.doPrivileged(action);
596 thread.start();
597 } else {
598 r.run();
599 }
600 }
601 }
602
603 private MostRecentKeyValue mostRecentKeyValue = null;
604 private MostRecentKeyValue shadowMostRecentKeyValue = null;
605
606 /**
607 * Returns the value to which the specified key is mapped in this context.
608 *
609 * @param key a key in the AppContext.
610 * @return the value to which the key is mapped in this AppContext;
611 * <code>null</code> if the key is not mapped to any value.
612 * @see #put(Object, Object)
613 * @since 1.2
614 */
615 public Object get(Object key) {
616 /*
617 * The most recent reference should be updated inside a synchronized
618 * block to avoid a race when put() and get() are executed in
619 * parallel on different threads.
620 */
621 synchronized (table) {
622 // Note: this most recent key/value caching is thread-hot.
623 // A simple test using SwingSet found that 72% of lookups
624 // were matched using the most recent key/value. By instantiating
625 // a simple MostRecentKeyValue object on cache misses, the
626 // cache hits can be processed without synchronization.
627
628 MostRecentKeyValue recent = mostRecentKeyValue;
629 if ((recent != null) && (recent.key == key)) {
630 return recent.value;
631 }
632
633 Object value = table.get(key);
634 if(mostRecentKeyValue == null) {
635 mostRecentKeyValue = new MostRecentKeyValue(key, value);
636 shadowMostRecentKeyValue = new MostRecentKeyValue(key, value);
637 } else {
638 MostRecentKeyValue auxKeyValue = mostRecentKeyValue;
639 shadowMostRecentKeyValue.setPair(key, value);
640 mostRecentKeyValue = shadowMostRecentKeyValue;
641 shadowMostRecentKeyValue = auxKeyValue;
642 }
643 return value;
644 }
645 }
646
647 /**
648 * Maps the specified <code>key</code> to the specified
649 * <code>value</code> in this AppContext. Neither the key nor the
650 * value can be <code>null</code>.
651 * <p>
652 * The value can be retrieved by calling the <code>get</code> method
653 * with a key that is equal to the original key.
654 *
655 * @param key the AppContext key.
656 * @param value the value.
657 * @return the previous value of the specified key in this
658 * AppContext, or <code>null</code> if it did not have one.
659 * @exception NullPointerException if the key or value is
660 * <code>null</code>.
661 * @see #get(Object)
662 * @since 1.2
663 */
664 public Object put(Object key, Object value) {
665 synchronized (table) {
666 MostRecentKeyValue recent = mostRecentKeyValue;
667 if ((recent != null) && (recent.key == key))
668 recent.value = value;
669 return table.put(key, value);
670 }
671 }
672
673 /**
674 * Removes the key (and its corresponding value) from this
675 * AppContext. This method does nothing if the key is not in the
676 * AppContext.
677 *
678 * @param key the key that needs to be removed.
679 * @return the value to which the key had been mapped in this AppContext,
680 * or <code>null</code> if the key did not have a mapping.
681 * @since 1.2
682 */
683 public Object remove(Object key) {
684 synchronized (table) {
685 MostRecentKeyValue recent = mostRecentKeyValue;
686 if ((recent != null) && (recent.key == key))
687 recent.value = null;
688 return table.remove(key);
689 }
690 }
691
692 /**
693 * Returns the root ThreadGroup for all Threads contained within
694 * this AppContext.
695 * @since 1.2
696 */
697 public ThreadGroup getThreadGroup() {
698 return threadGroup;
699 }
700
701 /**
702 * Returns the context ClassLoader that was used to create this
703 * AppContext.
704 *
705 * @see java.lang.Thread#getContextClassLoader
706 */
707 public ClassLoader getContextClassLoader() {
708 return contextClassLoader;
709 }
710
711 /**
712 * Returns a string representation of this AppContext.
713 * @since 1.2
714 */
715 @Override
716 public String toString() {
717 return getClass().getName() + "[threadGroup=" + threadGroup.getName() + "]";
718 }
719
720 /**
721 * Returns an array of all the property change listeners
722 * registered on this component.
723 *
724 * @return all of this component's <code>PropertyChangeListener</code>s
725 * or an empty array if no property change
726 * listeners are currently registered
727 *
728 * @see #addPropertyChangeListener
729 * @see #removePropertyChangeListener
730 * @see #getPropertyChangeListeners(java.lang.String)
731 * @see java.beans.PropertyChangeSupport#getPropertyChangeListeners
732 * @since 1.4
733 */
734 public synchronized PropertyChangeListener[] getPropertyChangeListeners() {
735 if (changeSupport == null) {
736 return new PropertyChangeListener[0];
737 }
738 return changeSupport.getPropertyChangeListeners();
739 }
740
741 /**
742 * Adds a PropertyChangeListener to the listener list for a specific
743 * property. The specified property may be one of the following:
744 * <ul>
745 * <li>if this AppContext is disposed ("disposed")</li>
746 * </ul>
747 * <ul>
748 * <li>if this AppContext's unowned Windows have been disposed
749 * ("guidisposed"). Code to cleanup after the GUI is disposed
750 * (such as LookAndFeel.uninitialize()) should execute in response to
751 * this property being fired. Notifications for the "guidisposed"
752 * property are sent on the event dispatch thread.</li>
753 * </ul>
754 * <p>
755 * If listener is null, no exception is thrown and no action is performed.
756 *
757 * @param propertyName one of the property names listed above
758 * @param listener the PropertyChangeListener to be added
759 *
760 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
761 * @see #getPropertyChangeListeners(java.lang.String)
762 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
763 */
764 public synchronized void addPropertyChangeListener(
765 String propertyName,
766 PropertyChangeListener listener) {
767 if (listener == null) {
768 return;
769 }
770 if (changeSupport == null) {
771 changeSupport = new PropertyChangeSupport(this);
772 }
773 changeSupport.addPropertyChangeListener(propertyName, listener);
774 }
775
776 /**
777 * Removes a PropertyChangeListener from the listener list for a specific
778 * property. This method should be used to remove PropertyChangeListeners
779 * that were registered for a specific bound property.
780 * <p>
781 * If listener is null, no exception is thrown and no action is performed.
782 *
783 * @param propertyName a valid property name
784 * @param listener the PropertyChangeListener to be removed
785 *
786 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
787 * @see #getPropertyChangeListeners(java.lang.String)
788 * @see #removePropertyChangeListener(java.beans.PropertyChangeListener)
789 */
790 public synchronized void removePropertyChangeListener(
791 String propertyName,
792 PropertyChangeListener listener) {
793 if (listener == null || changeSupport == null) {
794 return;
795 }
796 changeSupport.removePropertyChangeListener(propertyName, listener);
797 }
798
799 /**
800 * Returns an array of all the listeners which have been associated
801 * with the named property.
802 *
803 * @return all of the <code>PropertyChangeListeners</code> associated with
804 * the named property or an empty array if no listeners have
805 * been added
806 *
807 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
808 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
809 * @see #getPropertyChangeListeners
810 * @since 1.4
811 */
812 public synchronized PropertyChangeListener[] getPropertyChangeListeners(
813 String propertyName) {
814 if (changeSupport == null) {
815 return new PropertyChangeListener[0];
816 }
817 return changeSupport.getPropertyChangeListeners(propertyName);
818 }
819
820 // Set up JavaAWTAccess in SharedSecrets
821 static {
822 sun.misc.SharedSecrets.setJavaAWTAccess(new sun.misc.JavaAWTAccess() {
823 public Object get(Object key) {
824 AppContext ac = getAppContext();
825 return (ac == null) ? null : ac.get(key);
826 }
827 public void put(Object key, Object value) {
828 AppContext ac = getAppContext();
829 if (ac != null) {
830 ac.put(key, value);
831 }
832 }
833 public void remove(Object key) {
834 AppContext ac = getAppContext();
835 if (ac != null) {
836 ac.remove(key);
837 }
838 }
839 public boolean isDisposed() {
840 AppContext ac = getAppContext();
841 return (ac == null) ? true : ac.isDisposed();
842 }
843 public boolean isMainAppContext() {
844 return (numAppContexts.get() == 1 && mainAppContext != null);
845 }
846
847 private boolean hasRootThreadGroup(final AppContext ecx) {
848 return AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
849 @Override
850 public Boolean run() {
851 return ecx.threadGroup.getParent() == null;
852 }
853 });
854 }
855
856 /**
857 * Returns the AppContext used for applet logging isolation, or null if
858 * the default global context can be used.
859 * If there's no applet, or if the caller is a stand alone application,
860 * or running in the main app context, returns null.
861 * Otherwise, returns the AppContext of the calling applet.
862 * @return null if the global default context can be used,
863 * an AppContext otherwise.
864 **/
865 public Object getAppletContext() {
866 // There's no AppContext: return null.
867 // No need to call getAppContext() if numAppContext == 0:
868 // it means that no AppContext has been created yet, and
869 // we don't want to trigger the creation of a main app
870 // context since we don't need it.
871 if (numAppContexts.get() == 0) return null;
872
873 // Get the context from the security manager
874 AppContext ecx = getExecutionAppContext();
875
876 // Not sure we really need to re-check numAppContexts here.
877 // If all applets have gone away then we could have a
878 // numAppContexts coming back to 0. So we recheck
879 // it here because we don't want to trigger the
880 // creation of a main AppContext in that case.
881 // This is probably not 100% MT-safe but should reduce
882 // the window of opportunity in which that issue could
883 // happen.
884 if (numAppContexts.get() > 0) {
885 // Defaults to thread group caching.
886 // This is probably not required as we only really need
887 // isolation in a deployed applet environment, in which
888 // case ecx will not be null when we reach here
889 // However it helps emulate the deployed environment,
890 // in tests for instance.
891 ecx = ecx != null ? ecx : getAppContext();
892 }
893
894 // getAppletContext() may be called when initializing the main
895 // app context - in which case mainAppContext will still be
896 // null. To work around this issue we simply use
897 // AppContext.threadGroup.getParent() == null instead, since
898 // mainAppContext is the only AppContext which should have
899 // the root TG as its thread group.
900 // See: JDK-8023258
901 final boolean isMainAppContext = ecx == null
902 || mainAppContext == ecx
903 || mainAppContext == null && hasRootThreadGroup(ecx);
904
905 return isMainAppContext ? null : ecx;
906 }
907
908 });
909 }
910 }
911
912 final class MostRecentKeyValue {
913 Object key;
914 Object value;
915 MostRecentKeyValue(Object k, Object v) {
916 key = k;
917 value = v;
918 }
919 void setPair(Object k, Object v) {
920 key = k;
921 value = v;
922 }
923 }