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 final 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 final 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 return null; 335 } 336 context = threadGroup2appContext.get(threadGroup); 337 } 338 339 // In case we did anything in the above while loop, we add 340 // all the intermediate ThreadGroups to threadGroup2appContext 341 // so we won't spin again. 342 for (ThreadGroup tg = currentThreadGroup; tg != threadGroup; tg = tg.getParent()) { 343 threadGroup2appContext.put(tg, context); 344 } 345 346 // Now we're done, so we cache the latest key/value pair. 347 threadAppContext.set(context); 348 349 return context; 350 } 351 }); 352 } 353 354 return appContext; 355 } 356 357 /** 358 * Returns true if the specified AppContext is the main AppContext. 359 * 360 * @param ctx the context to compare with the main context 361 * @return true if the specified AppContext is the main AppContext. 362 * @since 1.8 363 */ 364 public final static boolean isMainContext(AppContext ctx) { 365 return (ctx != null && ctx == mainAppContext); 366 } 367 368 private final static AppContext getExecutionAppContext() { 369 SecurityManager securityManager = System.getSecurityManager(); 370 if ((securityManager != null) && 371 (securityManager instanceof AWTSecurityManager)) 372 { 373 AWTSecurityManager awtSecMgr = (AWTSecurityManager) securityManager; 374 AppContext secAppContext = awtSecMgr.getAppContext(); 375 return secAppContext; // Return what we're told 376 } 377 return null; 378 } 379 380 private long DISPOSAL_TIMEOUT = 5000; // Default to 5-second timeout 381 // for disposal of all Frames 382 // (we wait for this time twice, 383 // once for dispose(), and once 384 // to clear the EventQueue). 385 386 private long THREAD_INTERRUPT_TIMEOUT = 1000; 387 // Default to 1-second timeout for all 388 // interrupted Threads to exit, and another 389 // 1 second for all stopped Threads to die. 390 391 /** 392 * Disposes of this AppContext, all of its top-level Frames, and 393 * all Threads and ThreadGroups contained within it. 394 * 395 * This method must be called from a Thread which is not contained 396 * within this AppContext. 397 * 398 * @exception IllegalThreadStateException if the current thread is 399 * contained within this AppContext 400 * @since 1.2 401 */ 402 public void dispose() throws IllegalThreadStateException { 403 // Check to be sure that the current Thread isn't in this AppContext 404 if (this.threadGroup.parentOf(Thread.currentThread().getThreadGroup())) { 405 throw new IllegalThreadStateException( 406 "Current Thread is contained within AppContext to be disposed." 407 ); 408 } 409 410 synchronized(this) { 411 if (this.state != State.VALID) { 412 return; // If already disposed or being disposed, bail. 413 } 414 415 this.state = State.BEING_DISPOSED; 416 } 417 418 final PropertyChangeSupport changeSupport = this.changeSupport; 419 if (changeSupport != null) { 420 changeSupport.firePropertyChange(DISPOSED_PROPERTY_NAME, false, true); 421 } 422 423 // First, we post an InvocationEvent to be run on the 424 // EventDispatchThread which disposes of all top-level Frames and TrayIcons 425 426 final Object notificationLock = new Object(); 427 428 Runnable runnable = new Runnable() { 429 public void run() { 430 Window[] windowsToDispose = Window.getOwnerlessWindows(); 431 for (Window w : windowsToDispose) { 432 try { 433 w.dispose(); 434 } catch (Throwable t) { 435 log.finer("exception occurred while disposing app context", t); 436 } 437 } 438 AccessController.doPrivileged(new PrivilegedAction<Void>() { 439 public Void run() { 440 if (!GraphicsEnvironment.isHeadless() && SystemTray.isSupported()) 441 { 442 SystemTray systemTray = SystemTray.getSystemTray(); 443 TrayIcon[] trayIconsToDispose = systemTray.getTrayIcons(); 444 for (TrayIcon ti : trayIconsToDispose) { 445 systemTray.remove(ti); 446 } 447 } 448 return null; 449 } 450 }); 451 // Alert PropertyChangeListeners that the GUI has been disposed. 452 if (changeSupport != null) { 453 changeSupport.firePropertyChange(GUI_DISPOSED, false, true); 454 } 455 synchronized(notificationLock) { 456 notificationLock.notifyAll(); // Notify caller that we're done 457 } 458 } 459 }; 460 synchronized(notificationLock) { 461 SunToolkit.postEvent(this, 462 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable)); 463 try { 464 notificationLock.wait(DISPOSAL_TIMEOUT); 465 } catch (InterruptedException e) { } 466 } 467 468 // Next, we post another InvocationEvent to the end of the 469 // EventQueue. When it's executed, we know we've executed all 470 // events in the queue. 471 472 runnable = new Runnable() { public void run() { 473 synchronized(notificationLock) { 474 notificationLock.notifyAll(); // Notify caller that we're done 475 } 476 } }; 477 synchronized(notificationLock) { 478 SunToolkit.postEvent(this, 479 new InvocationEvent(Toolkit.getDefaultToolkit(), runnable)); 480 try { 481 notificationLock.wait(DISPOSAL_TIMEOUT); 482 } catch (InterruptedException e) { } 483 } 484 485 // We are done with posting events, so change the state to disposed 486 synchronized(this) { 487 this.state = State.DISPOSED; 488 } 489 490 // Next, we interrupt all Threads in the ThreadGroup 491 this.threadGroup.interrupt(); 492 // Note, the EventDispatchThread we've interrupted may dump an 493 // InterruptedException to the console here. This needs to be 494 // fixed in the EventDispatchThread, not here. 495 496 // Next, we sleep 10ms at a time, waiting for all of the active 497 // Threads in the ThreadGroup to exit. 498 499 long startTime = System.currentTimeMillis(); 500 long endTime = startTime + THREAD_INTERRUPT_TIMEOUT; 501 while ((this.threadGroup.activeCount() > 0) && 502 (System.currentTimeMillis() < endTime)) { 503 try { 504 Thread.sleep(10); 505 } catch (InterruptedException e) { } 506 } 507 508 // Then, we stop any remaining Threads 509 this.threadGroup.stop(); 510 511 // Next, we sleep 10ms at a time, waiting for all of the active 512 // Threads in the ThreadGroup to die. 513 514 startTime = System.currentTimeMillis(); 515 endTime = startTime + THREAD_INTERRUPT_TIMEOUT; 516 while ((this.threadGroup.activeCount() > 0) && 517 (System.currentTimeMillis() < endTime)) { 518 try { 519 Thread.sleep(10); 520 } catch (InterruptedException e) { } 521 } 522 523 // Next, we remove this and all subThreadGroups from threadGroup2appContext 524 int numSubGroups = this.threadGroup.activeGroupCount(); 525 if (numSubGroups > 0) { 526 ThreadGroup [] subGroups = new ThreadGroup[numSubGroups]; 527 numSubGroups = this.threadGroup.enumerate(subGroups); 528 for (int subGroup = 0; subGroup < numSubGroups; subGroup++) { 529 threadGroup2appContext.remove(subGroups[subGroup]); 530 } 531 } 532 threadGroup2appContext.remove(this.threadGroup); 533 534 threadAppContext.set(null); 535 536 // Finally, we destroy the ThreadGroup entirely. 537 try { 538 this.threadGroup.destroy(); 539 } catch (IllegalThreadStateException e) { 540 // Fired if not all the Threads died, ignore it and proceed 541 } 542 543 synchronized (table) { 544 this.table.clear(); // Clear out the Hashtable to ease garbage collection 545 } 546 547 numAppContexts.decrementAndGet(); 548 549 mostRecentKeyValue = null; 550 } 551 552 static final class PostShutdownEventRunnable implements Runnable { 553 private final AppContext appContext; 554 555 public PostShutdownEventRunnable(AppContext ac) { 556 appContext = ac; 557 } 558 559 public void run() { 560 final EventQueue eq = (EventQueue)appContext.get(EVENT_QUEUE_KEY); 561 if (eq != null) { 562 eq.postEvent(AWTAutoShutdown.getShutdownEvent()); 563 } 564 } 565 } 566 567 static final class CreateThreadAction implements PrivilegedAction<Thread> { 568 private final AppContext appContext; 569 private final Runnable runnable; 570 571 public CreateThreadAction(AppContext ac, Runnable r) { 572 appContext = ac; 573 runnable = r; 574 } 575 576 public Thread run() { 577 Thread t = new Thread(appContext.getThreadGroup(), runnable); 578 t.setContextClassLoader(appContext.getContextClassLoader()); 579 t.setPriority(Thread.NORM_PRIORITY + 1); 580 t.setDaemon(true); 581 return t; 582 } 583 } 584 585 static void stopEventDispatchThreads() { 586 for (AppContext appContext: getAppContexts()) { 587 if (appContext.isDisposed()) { 588 continue; 589 } 590 Runnable r = new PostShutdownEventRunnable(appContext); 591 // For security reasons EventQueue.postEvent should only be called 592 // on a thread that belongs to the corresponding thread group. 593 if (appContext != AppContext.getAppContext()) { 594 // Create a thread that belongs to the thread group associated 595 // with the AppContext and invokes EventQueue.postEvent. 596 PrivilegedAction<Thread> action = new CreateThreadAction(appContext, r); 597 Thread thread = AccessController.doPrivileged(action); 598 thread.start(); 599 } else { 600 r.run(); 601 } 602 } 603 } 604 605 private MostRecentKeyValue mostRecentKeyValue = null; 606 private MostRecentKeyValue shadowMostRecentKeyValue = null; 607 608 /** 609 * Returns the value to which the specified key is mapped in this context. 610 * 611 * @param key a key in the AppContext. 612 * @return the value to which the key is mapped in this AppContext; 613 * <code>null</code> if the key is not mapped to any value. 614 * @see #put(Object, Object) 615 * @since 1.2 616 */ 617 public Object get(Object key) { 618 /* 619 * The most recent reference should be updated inside a synchronized 620 * block to avoid a race when put() and get() are executed in 621 * parallel on different threads. 622 */ 623 synchronized (table) { 624 // Note: this most recent key/value caching is thread-hot. 625 // A simple test using SwingSet found that 72% of lookups 626 // were matched using the most recent key/value. By instantiating 627 // a simple MostRecentKeyValue object on cache misses, the 628 // cache hits can be processed without synchronization. 629 630 MostRecentKeyValue recent = mostRecentKeyValue; 631 if ((recent != null) && (recent.key == key)) { 632 return recent.value; 633 } 634 635 Object value = table.get(key); 636 if(mostRecentKeyValue == null) { 637 mostRecentKeyValue = new MostRecentKeyValue(key, value); 638 shadowMostRecentKeyValue = new MostRecentKeyValue(key, value); 639 } else { 640 MostRecentKeyValue auxKeyValue = mostRecentKeyValue; 641 shadowMostRecentKeyValue.setPair(key, value); 642 mostRecentKeyValue = shadowMostRecentKeyValue; 643 shadowMostRecentKeyValue = auxKeyValue; 644 } 645 return value; 646 } 647 } 648 649 /** 650 * Maps the specified <code>key</code> to the specified 651 * <code>value</code> in this AppContext. Neither the key nor the 652 * value can be <code>null</code>. 653 * <p> 654 * The value can be retrieved by calling the <code>get</code> method 655 * with a key that is equal to the original key. 656 * 657 * @param key the AppContext key. 658 * @param value the value. 659 * @return the previous value of the specified key in this 660 * AppContext, or <code>null</code> if it did not have one. 661 * @exception NullPointerException if the key or value is 662 * <code>null</code>. 663 * @see #get(Object) 664 * @since 1.2 665 */ 666 public Object put(Object key, Object value) { 667 synchronized (table) { 668 MostRecentKeyValue recent = mostRecentKeyValue; 669 if ((recent != null) && (recent.key == key)) 670 recent.value = value; 671 return table.put(key, value); 672 } 673 } 674 675 /** 676 * Removes the key (and its corresponding value) from this 677 * AppContext. This method does nothing if the key is not in the 678 * AppContext. 679 * 680 * @param key the key that needs to be removed. 681 * @return the value to which the key had been mapped in this AppContext, 682 * or <code>null</code> if the key did not have a mapping. 683 * @since 1.2 684 */ 685 public Object remove(Object key) { 686 synchronized (table) { 687 MostRecentKeyValue recent = mostRecentKeyValue; 688 if ((recent != null) && (recent.key == key)) 689 recent.value = null; 690 return table.remove(key); 691 } 692 } 693 694 /** 695 * Returns the root ThreadGroup for all Threads contained within 696 * this AppContext. 697 * @since 1.2 698 */ 699 public ThreadGroup getThreadGroup() { 700 return threadGroup; 701 } 702 703 /** 704 * Returns the context ClassLoader that was used to create this 705 * AppContext. 706 * 707 * @see java.lang.Thread#getContextClassLoader 708 */ 709 public ClassLoader getContextClassLoader() { 710 return contextClassLoader; 711 } 712 713 /** 714 * Returns a string representation of this AppContext. 715 * @since 1.2 716 */ 717 @Override 718 public String toString() { 719 return getClass().getName() + "[threadGroup=" + threadGroup.getName() + "]"; 720 } 721 722 /** 723 * Returns an array of all the property change listeners 724 * registered on this component. 725 * 726 * @return all of this component's <code>PropertyChangeListener</code>s 727 * or an empty array if no property change 728 * listeners are currently registered 729 * 730 * @see #addPropertyChangeListener 731 * @see #removePropertyChangeListener 732 * @see #getPropertyChangeListeners(java.lang.String) 733 * @see java.beans.PropertyChangeSupport#getPropertyChangeListeners 734 * @since 1.4 735 */ 736 public synchronized PropertyChangeListener[] getPropertyChangeListeners() { 737 if (changeSupport == null) { 738 return new PropertyChangeListener[0]; 739 } 740 return changeSupport.getPropertyChangeListeners(); 741 } 742 743 /** 744 * Adds a PropertyChangeListener to the listener list for a specific 745 * property. The specified property may be one of the following: 746 * <ul> 747 * <li>if this AppContext is disposed ("disposed")</li> 748 * </ul> 749 * <ul> 750 * <li>if this AppContext's unowned Windows have been disposed 751 * ("guidisposed"). Code to cleanup after the GUI is disposed 752 * (such as LookAndFeel.uninitialize()) should execute in response to 753 * this property being fired. Notifications for the "guidisposed" 754 * property are sent on the event dispatch thread.</li> 755 * </ul> 756 * <p> 757 * If listener is null, no exception is thrown and no action is performed. 758 * 759 * @param propertyName one of the property names listed above 760 * @param listener the PropertyChangeListener to be added 761 * 762 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) 763 * @see #getPropertyChangeListeners(java.lang.String) 764 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) 765 */ 766 public synchronized void addPropertyChangeListener( 767 String propertyName, 768 PropertyChangeListener listener) { 769 if (listener == null) { 770 return; 771 } 772 if (changeSupport == null) { 773 changeSupport = new PropertyChangeSupport(this); 774 } 775 changeSupport.addPropertyChangeListener(propertyName, listener); 776 } 777 778 /** 779 * Removes a PropertyChangeListener from the listener list for a specific 780 * property. This method should be used to remove PropertyChangeListeners 781 * that were registered for a specific bound property. 782 * <p> 783 * If listener is null, no exception is thrown and no action is performed. 784 * 785 * @param propertyName a valid property name 786 * @param listener the PropertyChangeListener to be removed 787 * 788 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) 789 * @see #getPropertyChangeListeners(java.lang.String) 790 * @see #removePropertyChangeListener(java.beans.PropertyChangeListener) 791 */ 792 public synchronized void removePropertyChangeListener( 793 String propertyName, 794 PropertyChangeListener listener) { 795 if (listener == null || changeSupport == null) { 796 return; 797 } 798 changeSupport.removePropertyChangeListener(propertyName, listener); 799 } 800 801 /** 802 * Returns an array of all the listeners which have been associated 803 * with the named property. 804 * 805 * @return all of the <code>PropertyChangeListeners</code> associated with 806 * the named property or an empty array if no listeners have 807 * been added 808 * 809 * @see #addPropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) 810 * @see #removePropertyChangeListener(java.lang.String, java.beans.PropertyChangeListener) 811 * @see #getPropertyChangeListeners 812 * @since 1.4 813 */ 814 public synchronized PropertyChangeListener[] getPropertyChangeListeners( 815 String propertyName) { 816 if (changeSupport == null) { 817 return new PropertyChangeListener[0]; 818 } 819 return changeSupport.getPropertyChangeListeners(propertyName); 820 } 821 822 // Set up JavaAWTAccess in SharedSecrets 823 static { 824 sun.misc.SharedSecrets.setJavaAWTAccess(new sun.misc.JavaAWTAccess() { 825 private boolean hasRootThreadGroup(final AppContext ecx) { 826 return AccessController.doPrivileged(new PrivilegedAction<Boolean>() { 827 @Override 828 public Boolean run() { 829 return ecx.threadGroup.getParent() == null; 830 } 831 }); 832 } 833 834 /** 835 * Returns the AppContext used for applet logging isolation, or null if 836 * the default global context can be used. 837 * If there's no applet, or if the caller is a stand alone application, 838 * or running in the main app context, returns null. 839 * Otherwise, returns the AppContext of the calling applet. 840 * @return null if the global default context can be used, 841 * an AppContext otherwise. 842 **/ 843 public Object getAppletContext() { 844 // There's no AppContext: return null. 845 // No need to call getAppContext() if numAppContext == 0: 846 // it means that no AppContext has been created yet, and 847 // we don't want to trigger the creation of a main app 848 // context since we don't need it. 849 if (numAppContexts.get() == 0) return null; 850 851 // Get the context from the security manager 852 AppContext ecx = getExecutionAppContext(); 853 854 // Not sure we really need to re-check numAppContexts here. 855 // If all applets have gone away then we could have a 856 // numAppContexts coming back to 0. So we recheck 857 // it here because we don't want to trigger the 858 // creation of a main AppContext in that case. 859 // This is probably not 100% MT-safe but should reduce 860 // the window of opportunity in which that issue could 861 // happen. 862 if (numAppContexts.get() > 0) { 863 // Defaults to thread group caching. 864 // This is probably not required as we only really need 865 // isolation in a deployed applet environment, in which 866 // case ecx will not be null when we reach here 867 // However it helps emulate the deployed environment, 868 // in tests for instance. 869 ecx = ecx != null ? ecx : getAppContext(); 870 } 871 872 // getAppletContext() may be called when initializing the main 873 // app context - in which case mainAppContext will still be 874 // null. To work around this issue we simply use 875 // AppContext.threadGroup.getParent() == null instead, since 876 // mainAppContext is the only AppContext which should have 877 // the root TG as its thread group. 878 // See: JDK-8023258 879 final boolean isMainAppContext = ecx == null 880 || mainAppContext == ecx 881 || mainAppContext == null && hasRootThreadGroup(ecx); 882 883 return isMainAppContext ? null : ecx; 884 } 885 886 }); 887 } 888 889 public static <T> T getSoftReferenceValue(Object key, 890 Supplier<T> supplier) { 891 892 final AppContext appContext = AppContext.getAppContext(); 893 @SuppressWarnings("unchecked") 894 SoftReference<T> ref = (SoftReference<T>) appContext.get(key); 895 if (ref != null) { 896 final T object = ref.get(); 897 if (object != null) { 898 return object; 899 } 900 } 901 final T object = supplier.get(); 902 ref = new SoftReference<>(object); 903 appContext.put(key, ref); 904 return object; 905 } 906 } 907 908 final class MostRecentKeyValue { 909 Object key; 910 Object value; 911 MostRecentKeyValue(Object k, Object v) { 912 key = k; 913 value = v; 914 } 915 void setPair(Object k, Object v) { 916 key = k; 917 value = v; 918 } 919 }