1 /*
2 * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
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23 * questions.
24 */
25 package javax.swing;
26
27 import java.awt.Component;
28 import java.awt.Container;
29 import java.awt.Window;
30 import java.util.*;
31 import java.awt.FocusTraversalPolicy;
32 import sun.util.logging.PlatformLogger;
33 import java.lang.reflect.InvocationTargetException;
34 import java.lang.reflect.Method;
35 import sun.security.action.GetPropertyAction;
36 import java.security.AccessController;
37 import java.security.PrivilegedAction;
38
39 /**
40 * A FocusTraversalPolicy that determines traversal order by sorting the
41 * Components of a focus traversal cycle based on a given Comparator. Portions
42 * of the Component hierarchy that are not visible and displayable will not be
43 * included.
44 * <p>
45 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
46 * cycle. That is, during normal focus traversal, the Component
47 * traversed after a focus cycle root will be the focus-cycle-root's default
48 * Component to focus. This behavior can be disabled using the
49 * <code>setImplicitDownCycleTraversal</code> method.
50 * <p>
51 * By default, methods of this class with return a Component only if it is
52 * visible, displayable, enabled, and focusable. Subclasses can modify this
53 * behavior by overriding the <code>accept</code> method.
54 * <p>
55 * This policy takes into account <a
56 * href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal
57 * policy providers</a>. When searching for first/last/next/previous Component,
58 * if a focus traversal policy provider is encountered, its focus traversal
59 * policy is used to perform the search operation.
60 *
61 * @author David Mendenhall
62 *
63 * @see java.util.Comparator
64 * @since 1.4
65 */
66 public class SortingFocusTraversalPolicy
67 extends InternalFrameFocusTraversalPolicy
68 {
69 private Comparator<? super Component> comparator;
70 private boolean implicitDownCycleTraversal = true;
71
72 private PlatformLogger log = PlatformLogger.getLogger("javax.swing.SortingFocusTraversalPolicy");
73
74 /**
75 * Used by getComponentAfter and getComponentBefore for efficiency. In
76 * order to maintain compliance with the specification of
77 * FocusTraversalPolicy, if traversal wraps, we should invoke
78 * getFirstComponent or getLastComponent. These methods may be overriden in
79 * subclasses to behave in a non-generic way. However, in the generic case,
80 * these methods will simply return the first or last Components of the
81 * sorted list, respectively. Since getComponentAfter and
82 * getComponentBefore have already built the sorted list before determining
83 * that they need to invoke getFirstComponent or getLastComponent, the
84 * sorted list should be reused if possible.
85 */
86 transient private Container cachedRoot;
87 transient private List<Component> cachedCycle;
88
89 // Delegate our fitness test to ContainerOrder so that we only have to
90 // code the algorithm once.
91 private static final SwingContainerOrderFocusTraversalPolicy
92 fitnessTestPolicy = new SwingContainerOrderFocusTraversalPolicy();
93
94 final private int FORWARD_TRAVERSAL = 0;
95 final private int BACKWARD_TRAVERSAL = 1;
96
97 /*
98 * When true (by default), the legacy merge-sort algo is used to sort an FTP cycle.
99 * When false, the default (tim-sort) algo is used, which may lead to an exception.
100 * See: JDK-8048887
101 */
102 private static final boolean legacySortingFTPEnabled;
103 private static final Method legacyMergeSortMethod;
104
105 static {
106 legacySortingFTPEnabled = "true".equals(AccessController.doPrivileged(
107 new GetPropertyAction("swing.legacySortingFTPEnabled", "true")));
108 legacyMergeSortMethod = legacySortingFTPEnabled ?
109 AccessController.doPrivileged(new PrivilegedAction<Method>() {
110 public Method run() {
111 try {
112 Method m = java.util.Arrays.class.getDeclaredMethod("legacyMergeSort",
113 new Class<?>[]{Object[].class,
114 Comparator.class});
115 m.setAccessible(true);
116 return m;
117 } catch (NoSuchMethodException e) {
118 // using default sorting algo
119 return null;
120 }
121 }
122 }) :
123 null;
124 }
125
126 /**
127 * Constructs a SortingFocusTraversalPolicy without a Comparator.
128 * Subclasses must set the Comparator using <code>setComparator</code>
129 * before installing this FocusTraversalPolicy on a focus cycle root or
130 * KeyboardFocusManager.
131 */
132 protected SortingFocusTraversalPolicy() {
133 }
134
135 /**
136 * Constructs a SortingFocusTraversalPolicy with the specified Comparator.
137 *
138 * @param comparator the {@code Comparator} to sort by
139 */
140 public SortingFocusTraversalPolicy(Comparator<? super Component> comparator) {
141 this.comparator = comparator;
142 }
143
144 private List<Component> getFocusTraversalCycle(Container aContainer) {
145 List<Component> cycle = new ArrayList<Component>();
146 enumerateAndSortCycle(aContainer, cycle);
147 return cycle;
148 }
149 private int getComponentIndex(List<Component> cycle, Component aComponent) {
150 int index;
151 try {
152 index = Collections.binarySearch(cycle, aComponent, comparator);
153 } catch (ClassCastException e) {
154 if (log.isLoggable(PlatformLogger.Level.FINE)) {
155 log.fine("### During the binary search for " + aComponent + " the exception occurred: ", e);
156 }
157 return -1;
158 }
159 if (index < 0) {
160 // Fix for 5070991.
161 // A workaround for a transitivity problem caused by ROW_TOLERANCE,
162 // because of that the component may be missed in the binary search.
163 // Try to search it again directly.
164 index = cycle.indexOf(aComponent);
165 }
166 return index;
167 }
168
169 private void enumerateAndSortCycle(Container focusCycleRoot, List<Component> cycle) {
170 if (focusCycleRoot.isShowing()) {
171 enumerateCycle(focusCycleRoot, cycle);
172 if (!legacySortingFTPEnabled ||
173 !legacySort(cycle, comparator))
174 {
175 Collections.sort(cycle, comparator);
176 }
177 }
178 }
179
180 private boolean legacySort(List<Component> l, Comparator<? super Component> c) {
181 if (legacyMergeSortMethod == null)
182 return false;
183
184 Object[] a = l.toArray();
185 try {
186 legacyMergeSortMethod.invoke(null, a, c);
187 } catch (IllegalAccessException | InvocationTargetException e) {
188 return false;
189 }
190 ListIterator<Component> i = l.listIterator();
191 for (Object e : a) {
192 i.next();
193 i.set((Component)e);
194 }
195 return true;
196 }
197
198 private void enumerateCycle(Container container, List<Component> cycle) {
199 if (!(container.isVisible() && container.isDisplayable())) {
200 return;
201 }
202
203 cycle.add(container);
204
205 Component[] components = container.getComponents();
206 for (Component comp : components) {
207 if (comp instanceof Container) {
208 Container cont = (Container)comp;
209
210 if (!cont.isFocusCycleRoot() &&
211 !cont.isFocusTraversalPolicyProvider() &&
212 !((cont instanceof JComponent) && ((JComponent)cont).isManagingFocus()))
213 {
214 enumerateCycle(cont, cycle);
215 continue;
216 }
217 }
218 cycle.add(comp);
219 }
220 }
221
222 Container getTopmostProvider(Container focusCycleRoot, Component aComponent) {
223 Container aCont = aComponent.getParent();
224 Container ftp = null;
225 while (aCont != focusCycleRoot && aCont != null) {
226 if (aCont.isFocusTraversalPolicyProvider()) {
227 ftp = aCont;
228 }
229 aCont = aCont.getParent();
230 }
231 if (aCont == null) {
232 return null;
233 }
234 return ftp;
235 }
236
237 /*
238 * Checks if a new focus cycle takes place and returns a Component to traverse focus to.
239 * @param comp a possible focus cycle root or policy provider
240 * @param traversalDirection the direction of the traversal
241 * @return a Component to traverse focus to if {@code comp} is a root or provider
242 * and implicit down-cycle is set, otherwise {@code null}
243 */
244 private Component getComponentDownCycle(Component comp, int traversalDirection) {
245 Component retComp = null;
246
247 if (comp instanceof Container) {
248 Container cont = (Container)comp;
249
250 if (cont.isFocusCycleRoot()) {
251 if (getImplicitDownCycleTraversal()) {
252 retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont);
253
254 if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) {
255 log.fine("### Transfered focus down-cycle to " + retComp +
256 " in the focus cycle root " + cont);
257 }
258 } else {
259 return null;
260 }
261 } else if (cont.isFocusTraversalPolicyProvider()) {
262 retComp = (traversalDirection == FORWARD_TRAVERSAL ?
263 cont.getFocusTraversalPolicy().getDefaultComponent(cont) :
264 cont.getFocusTraversalPolicy().getLastComponent(cont));
265
266 if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) {
267 log.fine("### Transfered focus to " + retComp + " in the FTP provider " + cont);
268 }
269 }
270 }
271 return retComp;
272 }
273
274 /**
275 * Returns the Component that should receive the focus after aComponent.
276 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
277 * <p>
278 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
279 * cycle. That is, during normal focus traversal, the Component
280 * traversed after a focus cycle root will be the focus-cycle-root's
281 * default Component to focus. This behavior can be disabled using the
282 * <code>setImplicitDownCycleTraversal</code> method.
283 * <p>
284 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
285 * traversal policy provider</a>, the focus is always transferred down-cycle.
286 *
287 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
288 * @param aComponent a (possibly indirect) child of aContainer, or
289 * aContainer itself
290 * @return the Component that should receive the focus after aComponent, or
291 * null if no suitable Component can be found
292 * @throws IllegalArgumentException if aContainer is not a focus cycle
293 * root of aComponent or a focus traversal policy provider, or if either aContainer or
294 * aComponent is null
295 */
296 public Component getComponentAfter(Container aContainer, Component aComponent) {
297 if (log.isLoggable(PlatformLogger.Level.FINE)) {
298 log.fine("### Searching in " + aContainer + " for component after " + aComponent);
299 }
300
301 if (aContainer == null || aComponent == null) {
302 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
303 }
304 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
305 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
306
307 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
308 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
309 }
310
311 // Before all the ckecks below we first see if it's an FTP provider or a focus cycle root.
312 // If it's the case just go down cycle (if it's set to "implicit").
313 Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL);
314 if (comp != null) {
315 return comp;
316 }
317
318 // See if the component is inside of policy provider.
319 Container provider = getTopmostProvider(aContainer, aComponent);
320 if (provider != null) {
321 if (log.isLoggable(PlatformLogger.Level.FINE)) {
322 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
323 }
324
325 // FTP knows how to find component after the given. We don't.
326 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
327 Component afterComp = policy.getComponentAfter(provider, aComponent);
328
329 // Null result means that we overstepped the limit of the FTP's cycle.
330 // In that case we must quit the cycle, otherwise return the component found.
331 if (afterComp != null) {
332 if (log.isLoggable(PlatformLogger.Level.FINE)) {
333 log.fine("### FTP returned " + afterComp);
334 }
335 return afterComp;
336 }
337 aComponent = provider;
338 }
339
340 List<Component> cycle = getFocusTraversalCycle(aContainer);
341
342 if (log.isLoggable(PlatformLogger.Level.FINE)) {
343 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
344 }
345
346 int index = getComponentIndex(cycle, aComponent);
347
348 if (index < 0) {
349 if (log.isLoggable(PlatformLogger.Level.FINE)) {
350 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
351 }
352 return getFirstComponent(aContainer);
353 }
354
355 for (index++; index < cycle.size(); index++) {
356 comp = cycle.get(index);
357 if (accept(comp)) {
358 return comp;
359 } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) {
360 return comp;
361 }
362 }
363
364 if (aContainer.isFocusCycleRoot()) {
365 this.cachedRoot = aContainer;
366 this.cachedCycle = cycle;
367
368 comp = getFirstComponent(aContainer);
369
370 this.cachedRoot = null;
371 this.cachedCycle = null;
372
373 return comp;
374 }
375 return null;
376 }
377
378 /**
379 * Returns the Component that should receive the focus before aComponent.
380 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
381 * <p>
382 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
383 * cycle. That is, during normal focus traversal, the Component
384 * traversed after a focus cycle root will be the focus-cycle-root's
385 * default Component to focus. This behavior can be disabled using the
386 * <code>setImplicitDownCycleTraversal</code> method.
387 * <p>
388 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
389 * traversal policy provider</a>, the focus is always transferred down-cycle.
390 *
391 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
392 * @param aComponent a (possibly indirect) child of aContainer, or
393 * aContainer itself
394 * @return the Component that should receive the focus before aComponent,
395 * or null if no suitable Component can be found
396 * @throws IllegalArgumentException if aContainer is not a focus cycle
397 * root of aComponent or a focus traversal policy provider, or if either aContainer or
398 * aComponent is null
399 */
400 public Component getComponentBefore(Container aContainer, Component aComponent) {
401 if (aContainer == null || aComponent == null) {
402 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
403 }
404 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
405 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
406
407 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
408 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
409 }
410
411 // See if the component is inside of policy provider.
412 Container provider = getTopmostProvider(aContainer, aComponent);
413 if (provider != null) {
414 if (log.isLoggable(PlatformLogger.Level.FINE)) {
415 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
416 }
417
418 // FTP knows how to find component after the given. We don't.
419 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
420 Component beforeComp = policy.getComponentBefore(provider, aComponent);
421
422 // Null result means that we overstepped the limit of the FTP's cycle.
423 // In that case we must quit the cycle, otherwise return the component found.
424 if (beforeComp != null) {
425 if (log.isLoggable(PlatformLogger.Level.FINE)) {
426 log.fine("### FTP returned " + beforeComp);
427 }
428 return beforeComp;
429 }
430 aComponent = provider;
431
432 // If the provider is traversable it's returned.
433 if (accept(aComponent)) {
434 return aComponent;
435 }
436 }
437
438 List<Component> cycle = getFocusTraversalCycle(aContainer);
439
440 if (log.isLoggable(PlatformLogger.Level.FINE)) {
441 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
442 }
443
444 int index = getComponentIndex(cycle, aComponent);
445
446 if (index < 0) {
447 if (log.isLoggable(PlatformLogger.Level.FINE)) {
448 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
449 }
450 return getLastComponent(aContainer);
451 }
452
453 Component comp;
454 Component tryComp;
455
456 for (index--; index>=0; index--) {
457 comp = cycle.get(index);
458 if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) {
459 return tryComp;
460 } else if (accept(comp)) {
461 return comp;
462 }
463 }
464
465 if (aContainer.isFocusCycleRoot()) {
466 this.cachedRoot = aContainer;
467 this.cachedCycle = cycle;
468
469 comp = getLastComponent(aContainer);
470
471 this.cachedRoot = null;
472 this.cachedCycle = null;
473
474 return comp;
475 }
476 return null;
477 }
478
479 /**
480 * Returns the first Component in the traversal cycle. This method is used
481 * to determine the next Component to focus when traversal wraps in the
482 * forward direction.
483 *
484 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
485 * first Component is to be returned
486 * @return the first Component in the traversal cycle of aContainer,
487 * or null if no suitable Component can be found
488 * @throws IllegalArgumentException if aContainer is null
489 */
490 public Component getFirstComponent(Container aContainer) {
491 List<Component> cycle;
492
493 if (log.isLoggable(PlatformLogger.Level.FINE)) {
494 log.fine("### Getting first component in " + aContainer);
495 }
496 if (aContainer == null) {
497 throw new IllegalArgumentException("aContainer cannot be null");
498 }
499
500 if (this.cachedRoot == aContainer) {
501 cycle = this.cachedCycle;
502 } else {
503 cycle = getFocusTraversalCycle(aContainer);
504 }
505
506 if (cycle.size() == 0) {
507 if (log.isLoggable(PlatformLogger.Level.FINE)) {
508 log.fine("### Cycle is empty");
509 }
510 return null;
511 }
512 if (log.isLoggable(PlatformLogger.Level.FINE)) {
513 log.fine("### Cycle is " + cycle);
514 }
515
516 for (Component comp : cycle) {
517 if (accept(comp)) {
518 return comp;
519 } else if (comp != aContainer &&
520 (comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null)
521 {
522 return comp;
523 }
524 }
525 return null;
526 }
527
528 /**
529 * Returns the last Component in the traversal cycle. This method is used
530 * to determine the next Component to focus when traversal wraps in the
531 * reverse direction.
532 *
533 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
534 * last Component is to be returned
535 * @return the last Component in the traversal cycle of aContainer,
536 * or null if no suitable Component can be found
537 * @throws IllegalArgumentException if aContainer is null
538 */
539 public Component getLastComponent(Container aContainer) {
540 List<Component> cycle;
541 if (log.isLoggable(PlatformLogger.Level.FINE)) {
542 log.fine("### Getting last component in " + aContainer);
543 }
544
545 if (aContainer == null) {
546 throw new IllegalArgumentException("aContainer cannot be null");
547 }
548
549 if (this.cachedRoot == aContainer) {
550 cycle = this.cachedCycle;
551 } else {
552 cycle = getFocusTraversalCycle(aContainer);
553 }
554
555 if (cycle.size() == 0) {
556 if (log.isLoggable(PlatformLogger.Level.FINE)) {
557 log.fine("### Cycle is empty");
558 }
559 return null;
560 }
561 if (log.isLoggable(PlatformLogger.Level.FINE)) {
562 log.fine("### Cycle is " + cycle);
563 }
564
565 for (int i= cycle.size() - 1; i >= 0; i--) {
566 Component comp = cycle.get(i);
567 if (accept(comp)) {
568 return comp;
569 } else if (comp instanceof Container && comp != aContainer) {
570 Container cont = (Container)comp;
571 if (cont.isFocusTraversalPolicyProvider()) {
572 return cont.getFocusTraversalPolicy().getLastComponent(cont);
573 }
574 }
575 }
576 return null;
577 }
578
579 /**
580 * Returns the default Component to focus. This Component will be the first
581 * to receive focus when traversing down into a new focus traversal cycle
582 * rooted at aContainer. The default implementation of this method
583 * returns the same Component as <code>getFirstComponent</code>.
584 *
585 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
586 * default Component is to be returned
587 * @return the default Component in the traversal cycle of aContainer,
588 * or null if no suitable Component can be found
589 * @see #getFirstComponent
590 * @throws IllegalArgumentException if aContainer is null
591 */
592 public Component getDefaultComponent(Container aContainer) {
593 return getFirstComponent(aContainer);
594 }
595
596 /**
597 * Sets whether this SortingFocusTraversalPolicy transfers focus down-cycle
598 * implicitly. If <code>true</code>, during normal focus traversal,
599 * the Component traversed after a focus cycle root will be the focus-
600 * cycle-root's default Component to focus. If <code>false</code>, the
601 * next Component in the focus traversal cycle rooted at the specified
602 * focus cycle root will be traversed instead. The default value for this
603 * property is <code>true</code>.
604 *
605 * @param implicitDownCycleTraversal whether this
606 * SortingFocusTraversalPolicy transfers focus down-cycle implicitly
607 * @see #getImplicitDownCycleTraversal
608 * @see #getFirstComponent
609 */
610 public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal) {
611 this.implicitDownCycleTraversal = implicitDownCycleTraversal;
612 }
613
614 /**
615 * Returns whether this SortingFocusTraversalPolicy transfers focus down-
616 * cycle implicitly. If <code>true</code>, during normal focus
617 * traversal, the Component traversed after a focus cycle root will be the
618 * focus-cycle-root's default Component to focus. If <code>false</code>,
619 * the next Component in the focus traversal cycle rooted at the specified
620 * focus cycle root will be traversed instead.
621 *
622 * @return whether this SortingFocusTraversalPolicy transfers focus down-
623 * cycle implicitly
624 * @see #setImplicitDownCycleTraversal
625 * @see #getFirstComponent
626 */
627 public boolean getImplicitDownCycleTraversal() {
628 return implicitDownCycleTraversal;
629 }
630
631 /**
632 * Sets the Comparator which will be used to sort the Components in a
633 * focus traversal cycle.
634 *
635 * @param comparator the Comparator which will be used for sorting
636 */
637 protected void setComparator(Comparator<? super Component> comparator) {
638 this.comparator = comparator;
639 }
640
641 /**
642 * Returns the Comparator which will be used to sort the Components in a
643 * focus traversal cycle.
644 *
645 * @return the Comparator which will be used for sorting
646 */
647 protected Comparator<? super Component> getComparator() {
648 return comparator;
649 }
650
651 /**
652 * Determines whether a Component is an acceptable choice as the new
653 * focus owner. By default, this method will accept a Component if and
654 * only if it is visible, displayable, enabled, and focusable.
655 *
656 * @param aComponent the Component whose fitness as a focus owner is to
657 * be tested
658 * @return <code>true</code> if aComponent is visible, displayable,
659 * enabled, and focusable; <code>false</code> otherwise
660 */
661 protected boolean accept(Component aComponent) {
662 return fitnessTestPolicy.accept(aComponent);
663 }
664 }
665
666 // Create our own subclass and change accept to public so that we can call
667 // accept.
668 @SuppressWarnings("serial") // JDK-implementation class
669 class SwingContainerOrderFocusTraversalPolicy
670 extends java.awt.ContainerOrderFocusTraversalPolicy
671 {
672 public boolean accept(Component aComponent) {
673 return super.accept(aComponent);
674 }
675 }