1 /*
2 * Copyright (c) 1998, 2013, 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 java.lang.ref.SoftReference;
46 import sun.util.logging.PlatformLogger;
47 import java.util.concurrent.locks.Condition;
48 import java.util.concurrent.locks.Lock;
49 import java.util.concurrent.locks.ReentrantLock;
50 import java.util.concurrent.atomic.AtomicInteger;
51 import java.util.function.Supplier;
52
53 /**
54 * The AppContext is a table referenced by ThreadGroup which stores
55 * application service instances. (If you are not writing an application
56 * service, or don't know what one is, please do not use this class.)
57 * The AppContext allows applet access to what would otherwise be
58 * potentially dangerous services, such as the ability to peek at
59 * EventQueues or change the look-and-feel of a Swing application.<p>
60 *
61 * Most application services use a singleton object to provide their
62 * services, either as a default (such as getSystemEventQueue or
63 * getDefaultToolkit) or as static methods with class data (System).
64 * The AppContext works with the former method by extending the concept
65 * of "default" to be ThreadGroup-specific. Application services
66 * lookup their singleton in the AppContext.<p>
67 *
68 * For example, here we have a Foo service, with its pre-AppContext
69 * code:<p>
70 * <code><pre>
71 * public class Foo {
72 * private static Foo defaultFoo = new Foo();
73 *
74 * public static Foo getDefaultFoo() {
75 * return defaultFoo;
76 * }
77 *
78 * ... Foo service methods
79 * }</pre></code><p>
80 *
81 * The problem with the above is that the Foo service is global in scope,
82 * so that applets and other untrusted code can execute methods on the
83 * single, shared Foo instance. The Foo service therefore either needs
84 * to block its use by untrusted code using a SecurityManager test, or
85 * restrict its capabilities so that it doesn't matter if untrusted code
86 * executes it.<p>
87 *
88 * Here's the Foo class written to use the AppContext:<p>
89 * <code><pre>
90 * public class Foo {
91 * public static Foo getDefaultFoo() {
92 * Foo foo = (Foo)AppContext.getAppContext().get(Foo.class);
93 * if (foo == null) {
94 * foo = new Foo();
95 * getAppContext().put(Foo.class, foo);
96 * }
97 * return foo;
98 * }
99 *
100 * ... Foo service methods
101 * }</pre></code><p>
102 *
103 * Since a separate AppContext can exist for each ThreadGroup, trusted
104 * and untrusted code have access to different Foo instances. This allows
105 * untrusted code access to "system-wide" services -- the service remains
106 * within the AppContext "sandbox". For example, say a malicious applet
107 * wants to peek all of the key events on the EventQueue to listen for
108 * passwords; if separate EventQueues are used for each ThreadGroup
109 * using AppContexts, the only key events that applet will be able to
110 * listen to are its own. A more reasonable applet request would be to
111 * change the Swing default look-and-feel; with that default stored in
112 * an AppContext, the applet's look-and-feel will change without
113 * disrupting other applets or potentially the browser itself.<p>
114 *
115 * Because the AppContext is a facility for safely extending application
116 * service support to applets, none of its methods may be blocked by a
117 * a SecurityManager check in a valid Java implementation. Applets may
118 * therefore safely invoke any of its methods without worry of being
119 * blocked.
120 *
121 * Note: If a SecurityManager is installed which derives from
122 * sun.awt.AWTSecurityManager, it may override the
123 * AWTSecurityManager.getAppContext() method to return the proper
124 * AppContext based on the execution context, in the case where
125 * the default ThreadGroup-based AppContext indexing would return
126 * the main "system" AppContext. For example, in an applet situation,
127 * if a system thread calls into an applet, rather than returning the
128 * main "system" AppContext (the one corresponding to the system thread),
129 * an installed AWTSecurityManager may return the applet's AppContext
130 * based on the execution context.
131 *
132 * @author Thomas Ball
133 * @author Fred Ecks
134 */
135 public final class AppContext {
136 private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.AppContext");
137
138 /* Since the contents of an AppContext are unique to each Java
139 * session, this class should never be serialized. */
140
141 /*
142 * The key to put()/get() the Java EventQueue into/from the AppContext.
143 */
144 public static final Object EVENT_QUEUE_KEY = new StringBuffer("EventQueue");
145
146 /*
147 * The keys to store EventQueue push/pop lock and condition.
148 */
149 public final static Object EVENT_QUEUE_LOCK_KEY = new StringBuilder("EventQueue.Lock");
150 public final static Object EVENT_QUEUE_COND_KEY = new StringBuilder("EventQueue.Condition");
151
152 /* A map of AppContexts, referenced by ThreadGroup.
153 */
154 private static final Map<ThreadGroup, AppContext> threadGroup2appContext =
155 Collections.synchronizedMap(new IdentityHashMap<ThreadGroup, AppContext>());
156
157 /**
158 * Returns a set containing all <code>AppContext</code>s.
159 */
160 public static Set<AppContext> getAppContexts() {
161 synchronized (threadGroup2appContext) {
162 return new HashSet<AppContext>(threadGroup2appContext.values());
163 }
164 }
165
166 /* The main "system" AppContext, used by everything not otherwise
167 contained in another AppContext. It is implicitly created for
168 standalone apps only (i.e. not applets)
169 */
170 private static volatile AppContext mainAppContext = null;
171
172 private static class GetAppContextLock {};
173 private final static Object getAppContextLock = new GetAppContextLock();
174
175 /*
176 * The hash map associated with this AppContext. A private delegate
177 * is used instead of subclassing HashMap so as to avoid all of
178 * HashMap's potentially risky methods, such as clear(), elements(),
179 * putAll(), etc.
180 */
181 private final Map<Object, Object> table = new HashMap<>();
182
183 private final ThreadGroup threadGroup;
184
185 /**
186 * If any <code>PropertyChangeListeners</code> have been registered,
187 * the <code>changeSupport</code> field describes them.
188 *
189 * @see #addPropertyChangeListener
190 * @see #removePropertyChangeListener
191 * @see #firePropertyChange
192 */
193 private PropertyChangeSupport changeSupport = null;
194
195 public static final String DISPOSED_PROPERTY_NAME = "disposed";
196 public static final String GUI_DISPOSED = "guidisposed";
197
198 private enum State {
199 VALID,
200 BEING_DISPOSED,
201 DISPOSED
202 };
203
204 private volatile State state = State.VALID;
205
206 public boolean isDisposed() {
207 return state == State.DISPOSED;
208 }
209
210 /*
211 * The total number of AppContexts, system-wide. This number is
212 * incremented at the beginning of the constructor, and decremented
213 * at the end of dispose(). getAppContext() checks to see if this
214 * number is 1. If so, it returns the sole AppContext without
215 * checking Thread.currentThread().
216 */
217 private static final AtomicInteger numAppContexts = new AtomicInteger(0);
218
219
220 /*
221 * The context ClassLoader that was used to create this AppContext.
222 */
223 private final ClassLoader contextClassLoader;
224
225 /**
226 * Constructor for AppContext. This method is <i>not</i> public,
227 * nor should it ever be used as such. The proper way to construct
228 * an AppContext is through the use of SunToolkit.createNewAppContext.
229 * A ThreadGroup is created for the new AppContext, a Thread is
230 * created within that ThreadGroup, and that Thread calls
231 * SunToolkit.createNewAppContext before calling anything else.
232 * That creates both the new AppContext and its EventQueue.
233 *
234 * @param threadGroup The ThreadGroup for the new AppContext
235 * @see sun.awt.SunToolkit
236 * @since 1.2
237 */
238 AppContext(ThreadGroup threadGroup) {
239 numAppContexts.incrementAndGet();
240
241 this.threadGroup = threadGroup;
242 threadGroup2appContext.put(threadGroup, this);
243
244 this.contextClassLoader =
245 AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
246 public ClassLoader run() {
247 return Thread.currentThread().getContextClassLoader();
248 }
249 });
250
251 // Initialize push/pop lock and its condition to be used by all the
252 // EventQueues within this AppContext
253 Lock eventQueuePushPopLock = new ReentrantLock();
254 put(EVENT_QUEUE_LOCK_KEY, eventQueuePushPopLock);
255 Condition eventQueuePushPopCond = eventQueuePushPopLock.newCondition();
256 put(EVENT_QUEUE_COND_KEY, eventQueuePushPopCond);
257 }
258
259 private static final ThreadLocal<AppContext> threadAppContext =
260 new ThreadLocal<AppContext>();
261
262 private static void initMainAppContext() {
263 // On the main Thread, we get the ThreadGroup, make a corresponding
264 // AppContext, and instantiate the Java EventQueue. This way, legacy
265 // code is unaffected by the move to multiple AppContext ability.
266 AccessController.doPrivileged(new PrivilegedAction<Void>() {
267 public Void run() {
268 ThreadGroup currentThreadGroup =
269 Thread.currentThread().getThreadGroup();
270 ThreadGroup parentThreadGroup = currentThreadGroup.getParent();
271 while (parentThreadGroup != null) {
272 // Find the root ThreadGroup to construct our main AppContext
273 currentThreadGroup = parentThreadGroup;
274 parentThreadGroup = currentThreadGroup.getParent();
275 }
276
277 mainAppContext = SunToolkit.createNewAppContext(currentThreadGroup);
278 return null;
279 }
280 });
281 }
282
283 /**
284 * Returns the appropriate AppContext for the caller,
285 * as determined by its ThreadGroup. If the main "system" AppContext
286 * would be returned and there's an AWTSecurityManager installed, it
287 * is called to get the proper AppContext based on the execution
288 * context.
289 *
290 * @return the AppContext for the caller.
291 * @see java.lang.ThreadGroup
292 * @since 1.2
293 */
294 public static AppContext getAppContext() {
295 // we are standalone app, return the main app context
296 if (numAppContexts.get() == 1 && mainAppContext != null) {
297 return mainAppContext;
298 }
299
300 AppContext appContext = threadAppContext.get();
301
302 if (null == appContext) {
303 appContext = AccessController.doPrivileged(new PrivilegedAction<AppContext>()
304 {
305 public AppContext run() {
306 // Get the current ThreadGroup, and look for it and its
307 // parents in the hash from ThreadGroup to AppContext --
308 // it should be found, because we use createNewContext()
309 // when new AppContext objects are created.
310 ThreadGroup currentThreadGroup = Thread.currentThread().getThreadGroup();
311 ThreadGroup threadGroup = currentThreadGroup;
312
313 // Special case: we implicitly create the main app context
314 // if no contexts have been created yet. This covers standalone apps
315 // and excludes applets because by the time applet starts
316 // a number of contexts have already been created by the plugin.
317 synchronized (getAppContextLock) {
318 if (numAppContexts.get() == 0) {
319 if (System.getProperty("javaplugin.version") == null &&
320 System.getProperty("javawebstart.version") == null) {
321 initMainAppContext();
322 } else if (System.getProperty("javafx.version") != null &&
323 threadGroup.getParent() != null) {
324 // Swing inside JavaFX case
325 SunToolkit.createNewAppContext();
326 }
327 }
328 }
329
330 AppContext context = threadGroup2appContext.get(threadGroup);
331 while (context == null) {
332 threadGroup = threadGroup.getParent();
333 if (threadGroup == null) {
334 // We've got up to the root thread group and did not find an AppContext
335 // Try to get it from the security manager
336 SecurityManager securityManager = System.getSecurityManager();
337 if (securityManager != null) {
338 ThreadGroup smThreadGroup = securityManager.getThreadGroup();
339 if (smThreadGroup != null) {
340 /*
341 * If we get this far then it's likely that
342 * the ThreadGroup does not actually belong
343 * to the applet, so do not cache it.
344 */
345 return threadGroup2appContext.get(smThreadGroup);
346 }
347 }
348 return null;
349 }
350 context = threadGroup2appContext.get(threadGroup);
351 }
352
353 // In case we did anything in the above while loop, we add
354 // all the intermediate ThreadGroups to threadGroup2appContext
355 // so we won't spin again.
356 for (ThreadGroup tg = currentThreadGroup; tg != threadGroup; tg = tg.getParent()) {
357 threadGroup2appContext.put(tg, context);
358 }
359
360 // Now we're done, so we cache the latest key/value pair.
361 threadAppContext.set(context);
362
363 return context;
364 }
365 });
366 }
367
368 return appContext;
369 }
370
371 /**
372 * Returns true if the specified AppContext is the main AppContext.
373 *
374 * @param ctx the context to compare with the main context
375 * @return true if the specified AppContext is the main AppContext.
376 * @since 1.8
377 */
378 public static boolean isMainContext(AppContext ctx) {
379 return (ctx != null && ctx == mainAppContext);
380 }
381
382 private static AppContext getExecutionAppContext() {
383 SecurityManager securityManager = System.getSecurityManager();
384 if ((securityManager != null) &&
385 (securityManager instanceof AWTSecurityManager))
386 {
387 AWTSecurityManager awtSecMgr = (AWTSecurityManager) securityManager;
388 AppContext secAppContext = awtSecMgr.getAppContext();
389 return secAppContext; // Return what we're told
390 }
391 return null;
392 }
393
394 private long DISPOSAL_TIMEOUT = 5000; // Default to 5-second timeout
395 // for disposal of all Frames
396 // (we wait for this time twice,
397 // once for dispose(), and once
398 // to clear the EventQueue).
399
400 private long THREAD_INTERRUPT_TIMEOUT = 1000;
401 // Default to 1-second timeout for all
402 // interrupted Threads to exit, and another
403 // 1 second for all stopped Threads to die.
404
405 /**
406 * Disposes of this AppContext, all of its top-level Frames, and
407 * all Threads and ThreadGroups contained within it.
408 *
409 * This method must be called from a Thread which is not contained
410 * within this AppContext.
411 *
412 * @exception IllegalThreadStateException if the current thread is
413 * contained within this AppContext
414 * @since 1.2
415 */
416 public void dispose() throws IllegalThreadStateException {
417 // Check to be sure that the current Thread isn't in this AppContext
418 if (this.threadGroup.parentOf(Thread.currentThread().getThreadGroup())) {
419 throw new IllegalThreadStateException(
420 "Current Thread is contained within AppContext to be disposed."
421 );
422 }
423
424 synchronized(this) {
425 if (this.state != State.VALID) {
426 return; // If already disposed or being disposed, bail.
427 }
428
429 this.state = State.BEING_DISPOSED;
430 }
431
432 final PropertyChangeSupport changeSupport = this.changeSupport;
433 if (changeSupport != null) {
434 changeSupport.firePropertyChange(DISPOSED_PROPERTY_NAME, false, true);
435 }
436
437 // First, we post an InvocationEvent to be run on the
438 // EventDispatchThread which disposes of all top-level Frames and TrayIcons
439
440 final Object notificationLock = new Object();
441
442 Runnable runnable = new Runnable() {
443 public void run() {
444 Window[] windowsToDispose = Window.getOwnerlessWindows();
445 for (Window w : windowsToDispose) {
446 try {
447 w.dispose();
448 } catch (Throwable t) {
449 log.finer("exception occurred while disposing app context", t);
450 }
451 }
452 AccessController.doPrivileged(new PrivilegedAction<Void>() {
453 public Void run() {
454 if (!GraphicsEnvironment.isHeadless() && SystemTray.isSupported())
455 {
456 SystemTray systemTray = SystemTray.getSystemTray();
457 TrayIcon[] trayIconsToDispose = systemTray.getTrayIcons();
458 for (TrayIcon ti : trayIconsToDispose) {
459 systemTray.remove(ti);
460 }
461 }
462 return null;
463 }
464 });
465 // Alert PropertyChangeListeners that the GUI has been disposed.
466 if (changeSupport != null) {
467 changeSupport.firePropertyChange(GUI_DISPOSED, false, true);
468 }
469 synchronized(notificationLock) {
470 notificationLock.notifyAll(); // Notify caller that we're done
471 }
472 }
473 };
474 synchronized(notificationLock) {
475 SunToolkit.postEvent(this,
476 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
477 try {
478 notificationLock.wait(DISPOSAL_TIMEOUT);
479 } catch (InterruptedException e) { }
480 }
481
482 // Next, we post another InvocationEvent to the end of the
483 // EventQueue. When it's executed, we know we've executed all
484 // events in the queue.
485
486 runnable = new Runnable() { public void run() {
487 synchronized(notificationLock) {
488 notificationLock.notifyAll(); // Notify caller that we're done
489 }
490 } };
491 synchronized(notificationLock) {
492 SunToolkit.postEvent(this,
493 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable));
494 try {
495 notificationLock.wait(DISPOSAL_TIMEOUT);
496 } catch (InterruptedException e) { }
497 }
498
499 // We are done with posting events, so change the state to disposed
500 synchronized(this) {
501 this.state = State.DISPOSED;
502 }
503
504 // Next, we interrupt all Threads in the ThreadGroup
505 this.threadGroup.interrupt();
506 // Note, the EventDispatchThread we've interrupted may dump an
507 // InterruptedException to the console here. This needs to be
508 // fixed in the EventDispatchThread, not here.
509
510 // Next, we sleep 10ms at a time, waiting for all of the active
511 // Threads in the ThreadGroup to exit.
512
513 long startTime = System.currentTimeMillis();
514 long endTime = startTime + THREAD_INTERRUPT_TIMEOUT;
515 while ((this.threadGroup.activeCount() > 0) &&
516 (System.currentTimeMillis() < endTime)) {
517 try {
518 Thread.sleep(10);
519 } catch (InterruptedException e) { }
520 }
521
522 // Then, we stop any remaining Threads
523 this.threadGroup.stop();
524
525 // Next, we sleep 10ms at a time, waiting for all of the active
526 // Threads in the ThreadGroup to die.
527
528 startTime = System.currentTimeMillis();
529 endTime = startTime + THREAD_INTERRUPT_TIMEOUT;
530 while ((this.threadGroup.activeCount() > 0) &&
531 (System.currentTimeMillis() < endTime)) {
532 try {
533 Thread.sleep(10);
534 } catch (InterruptedException e) { }
535 }
536
537 // Next, we remove this and all subThreadGroups from threadGroup2appContext
538 int numSubGroups = this.threadGroup.activeGroupCount();
539 if (numSubGroups > 0) {
540 ThreadGroup [] subGroups = new ThreadGroup[numSubGroups];
541 numSubGroups = this.threadGroup.enumerate(subGroups);
542 for (int subGroup = 0; subGroup < numSubGroups; subGroup++) {
543 threadGroup2appContext.remove(subGroups[subGroup]);
544 }
545 }
546 threadGroup2appContext.remove(this.threadGroup);
547
548 threadAppContext.set(null);
549
550 // Finally, we destroy the ThreadGroup entirely.
551 try {
552 this.threadGroup.destroy();
553 } catch (IllegalThreadStateException e) {
554 // Fired if not all the Threads died, ignore it and proceed
555 }
556
557 synchronized (table) {
558 this.table.clear(); // Clear out the Hashtable to ease garbage collection
559 }
560
561 numAppContexts.decrementAndGet();
562
563 mostRecentKeyValue = null;
564 }
565
566 static final class PostShutdownEventRunnable implements Runnable {
567 private final AppContext appContext;
568
569 public PostShutdownEventRunnable(AppContext ac) {
570 appContext = ac;
571 }
572
573 public void run() {
574 final EventQueue eq = (EventQueue)appContext.get(EVENT_QUEUE_KEY);
575 if (eq != null) {
576 eq.postEvent(AWTAutoShutdown.getShutdownEvent());
577 }
578 }
579 }
580
581 static final class CreateThreadAction implements PrivilegedAction<Thread> {
582 private final AppContext appContext;
583 private final Runnable runnable;
584
585 public CreateThreadAction(AppContext ac, Runnable r) {
586 appContext = ac;
587 runnable = r;
588 }
589
590 public Thread run() {
591 Thread t = new Thread(appContext.getThreadGroup(), runnable);
592 t.setContextClassLoader(appContext.getContextClassLoader());
593 t.setPriority(Thread.NORM_PRIORITY + 1);
594 t.setDaemon(true);
595 return t;
596 }
597 }
598
599 static void stopEventDispatchThreads() {
600 for (AppContext appContext: getAppContexts()) {
601 if (appContext.isDisposed()) {
602 continue;
603 }
604 Runnable r = new PostShutdownEventRunnable(appContext);
605 // For security reasons EventQueue.postEvent should only be called
606 // on a thread that belongs to the corresponding thread group.
607 if (appContext != AppContext.getAppContext()) {
608 // Create a thread that belongs to the thread group associated
609 // with the AppContext and invokes EventQueue.postEvent.
610 PrivilegedAction<Thread> action = new CreateThreadAction(appContext, r);
611 Thread thread = AccessController.doPrivileged(action);
612 thread.start();
613 } else {
614 r.run();
615 }
616 }
617 }
618
619 private MostRecentKeyValue mostRecentKeyValue = null;
620 private MostRecentKeyValue shadowMostRecentKeyValue = null;
621
622 /**
623 * Returns the value to which the specified key is mapped in this context.
624 *
625 * @param key a key in the AppContext.
626 * @return the value to which the key is mapped in this AppContext;
627 * <code>null</code> if the key is not mapped to any value.
628 * @see #put(Object, Object)
629 * @since 1.2
630 */
631 public Object get(Object key) {
632 /*
633 * The most recent reference should be updated inside a synchronized
634 * block to avoid a race when put() and get() are executed in
635 * parallel on different threads.
636 */
637 synchronized (table) {
638 // Note: this most recent key/value caching is thread-hot.
639 // A simple test using SwingSet found that 72% of lookups
640 // were matched using the most recent key/value. By instantiating
641 // a simple MostRecentKeyValue object on cache misses, the
642 // cache hits can be processed without synchronization.
643
644 MostRecentKeyValue recent = mostRecentKeyValue;
645 if ((recent != null) && (recent.key == key)) {
646 return recent.value;
647 }
648
649 Object value = table.get(key);
650 if(mostRecentKeyValue == null) {
651 mostRecentKeyValue = new MostRecentKeyValue(key, value);
652 shadowMostRecentKeyValue = new MostRecentKeyValue(key, value);
653 } else {
654 MostRecentKeyValue auxKeyValue = mostRecentKeyValue;
655 shadowMostRecentKeyValue.setPair(key, value);
656 mostRecentKeyValue = shadowMostRecentKeyValue;
657 shadowMostRecentKeyValue = auxKeyValue;
658 }
659 return value;
660 }
661 }
662
663 /**
664 * Maps the specified <code>key</code> to the specified
665 * <code>value</code> in this AppContext. Neither the key nor the
666 * value can be <code>null</code>.
667 * <p>
668 * The value can be retrieved by calling the <code>get</code> method
669 * with a key that is equal to the original key.
670 *
671 * @param key the AppContext key.
672 * @param value the value.
673 * @return the previous value of the specified key in this
674 * AppContext, or <code>null</code> if it did not have one.
675 * @exception NullPointerException if the key or value is
676 * <code>null</code>.
677 * @see #get(Object)
678 * @since 1.2
679 */
680 public Object put(Object key, Object value) {
681 synchronized (table) {
682 MostRecentKeyValue recent = mostRecentKeyValue;
683 if ((recent != null) && (recent.key == key))
684 recent.value = value;
685 return table.put(key, value);
686 }
687 }
688
689 /**
690 * Removes the key (and its corresponding value) from this
691 * AppContext. This method does nothing if the key is not in the
692 * AppContext.
693 *
694 * @param key the key that needs to be removed.
695 * @return the value to which the key had been mapped in this AppContext,
696 * or <code>null</code> if the key did not have a mapping.
697 * @since 1.2
698 */
699 public Object remove(Object key) {
700 synchronized (table) {
701 MostRecentKeyValue recent = mostRecentKeyValue;
702 if ((recent != null) && (recent.key == key))
703 recent.value = null;
704 return table.remove(key);
705 }
706 }
707
708 /**
709 * Returns the root ThreadGroup for all Threads contained within
710 * this AppContext.
711 * @since 1.2
712 */
713 public ThreadGroup getThreadGroup() {
714 return threadGroup;
715 }
716
717 /**
718 * Returns the context ClassLoader that was used to create this
719 * AppContext.
720 *
721 * @see java.lang.Thread#getContextClassLoader
722 */
723 public ClassLoader getContextClassLoader() {
724 return contextClassLoader;
725 }
726
727 /**
728 * Returns a string representation of this AppContext.
729 * @since 1.2
730 */
731 @Override
732 public String toString() {
733 return getClass().getName() + "[threadGroup=" + threadGroup.getName() + "]";
734 }
735
736 /**
737 * Returns an array of all the property change listeners
738 * registered on this component.
739 *
740 * @return all of this component's <code>PropertyChangeListener</code>s
741 * or an empty array if no property change
742 * listeners are currently registered
743 *
744 * @see #addPropertyChangeListener
745 * @see #removePropertyChangeListener
746 * @see #getPropertyChangeListeners(java.lang.String)
747 * @see java.beans.PropertyChangeSupport#getPropertyChangeListeners
748 * @since 1.4
749 */
750 public synchronized PropertyChangeListener[] getPropertyChangeListeners() {
751 if (changeSupport == null) {
752 return new PropertyChangeListener[0];
753 }
754 return changeSupport.getPropertyChangeListeners();
755 }
756
757 /**
758 * Adds a PropertyChangeListener to the listener list for a specific
759 * property. The specified property may be one of the following:
760 * <ul>
761 * <li>if this AppContext is disposed ("disposed")</li>
762 * </ul>
763 * <ul>
764 * <li>if this AppContext's unowned Windows have been disposed
765 * ("guidisposed"). Code to cleanup after the GUI is disposed
766 * (such as LookAndFeel.uninitialize()) should execute in response to
767 * this property being fired. Notifications for the "guidisposed"
768 * property are sent on the event dispatch thread.</li>
769 * </ul>
770 * <p>
771 * If listener is null, no exception is thrown and no action is performed.
772 *
773 * @param propertyName one of the property names listed above
774 * @param listener the PropertyChangeListener to be added
775 *
776 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
777 * @see #getPropertyChangeListeners(java.lang.String)
778 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
779 */
780 public synchronized void addPropertyChangeListener(
781 String propertyName,
782 PropertyChangeListener listener) {
783 if (listener == null) {
784 return;
785 }
786 if (changeSupport == null) {
787 changeSupport = new PropertyChangeSupport(this);
788 }
789 changeSupport.addPropertyChangeListener(propertyName, listener);
790 }
791
792 /**
793 * Removes a PropertyChangeListener from the listener list for a specific
794 * property. This method should be used to remove PropertyChangeListeners
795 * that were registered for a specific bound property.
796 * <p>
797 * If listener is null, no exception is thrown and no action is performed.
798 *
799 * @param propertyName a valid property name
800 * @param listener the PropertyChangeListener to be removed
801 *
802 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
803 * @see #getPropertyChangeListeners(java.lang.String)
804 * @see #removePropertyChangeListener(java.beans.PropertyChangeListener)
805 */
806 public synchronized void removePropertyChangeListener(
807 String propertyName,
808 PropertyChangeListener listener) {
809 if (listener == null || changeSupport == null) {
810 return;
811 }
812 changeSupport.removePropertyChangeListener(propertyName, listener);
813 }
814
815 /**
816 * Returns an array of all the listeners which have been associated
817 * with the named property.
818 *
819 * @return all of the <code>PropertyChangeListeners</code> associated with
820 * the named property or an empty array if no listeners have
821 * been added
822 *
823 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
824 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener)
825 * @see #getPropertyChangeListeners
826 * @since 1.4
827 */
828 public synchronized PropertyChangeListener[] getPropertyChangeListeners(
829 String propertyName) {
830 if (changeSupport == null) {
831 return new PropertyChangeListener[0];
832 }
833 return changeSupport.getPropertyChangeListeners(propertyName);
834 }
835
836 // Set up JavaAWTAccess in SharedSecrets
837 static {
838 sun.misc.SharedSecrets.setJavaAWTAccess(new sun.misc.JavaAWTAccess() {
839 private boolean hasRootThreadGroup(final AppContext ecx) {
840 return AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
841 @Override
842 public Boolean run() {
843 return ecx.threadGroup.getParent() == null;
844 }
845 });
846 }
847
848 /**
849 * Returns the AppContext used for applet logging isolation, or null if
850 * the default global context can be used.
851 * If there's no applet, or if the caller is a stand alone application,
852 * or running in the main app context, returns null.
853 * Otherwise, returns the AppContext of the calling applet.
854 * @return null if the global default context can be used,
855 * an AppContext otherwise.
856 **/
857 public Object getAppletContext() {
858 // There's no AppContext: return null.
859 // No need to call getAppContext() if numAppContext == 0:
860 // it means that no AppContext has been created yet, and
861 // we don't want to trigger the creation of a main app
862 // context since we don't need it.
863 if (numAppContexts.get() == 0) return null;
864
865 // Get the context from the security manager
866 AppContext ecx = getExecutionAppContext();
867
868 // Not sure we really need to re-check numAppContexts here.
869 // If all applets have gone away then we could have a
870 // numAppContexts coming back to 0. So we recheck
871 // it here because we don't want to trigger the
872 // creation of a main AppContext in that case.
873 // This is probably not 100% MT-safe but should reduce
874 // the window of opportunity in which that issue could
875 // happen.
876 if (numAppContexts.get() > 0) {
877 // Defaults to thread group caching.
878 // This is probably not required as we only really need
879 // isolation in a deployed applet environment, in which
880 // case ecx will not be null when we reach here
881 // However it helps emulate the deployed environment,
882 // in tests for instance.
883 ecx = ecx != null ? ecx : getAppContext();
884 }
885
886 // getAppletContext() may be called when initializing the main
887 // app context - in which case mainAppContext will still be
888 // null. To work around this issue we simply use
889 // AppContext.threadGroup.getParent() == null instead, since
890 // mainAppContext is the only AppContext which should have
891 // the root TG as its thread group.
892 // See: JDK-8023258
893 final boolean isMainAppContext = ecx == null
894 || mainAppContext == ecx
895 || mainAppContext == null && hasRootThreadGroup(ecx);
896
897 return isMainAppContext ? null : ecx;
898 }
899
900 });
901 }
902
903 public static <T> T getSoftReferenceValue(Object key,
904 Supplier<T> supplier) {
905
906 final AppContext appContext = AppContext.getAppContext();
907 @SuppressWarnings("unchecked")
908 SoftReference<T> ref = (SoftReference<T>) appContext.get(key);
909 if (ref != null) {
910 final T object = ref.get();
911 if (object != null) {
912 return object;
913 }
914 }
915 final T object = supplier.get();
916 ref = new SoftReference<>(object);
917 appContext.put(key, ref);
918 return object;
919 }
920 }
921
922 final class MostRecentKeyValue {
923 Object key;
924 Object value;
925 MostRecentKeyValue(Object k, Object v) {
926 key = k;
927 value = v;
928 }
929 void setPair(Object k, Object v) {
930 key = k;
931 value = v;
932 }
933 }