98 protected SortingFocusTraversalPolicy() {
99 }
100
101 /**
102 * Constructs a SortingFocusTraversalPolicy with the specified Comparator.
103 */
104 public SortingFocusTraversalPolicy(Comparator<? super Component> comparator) {
105 this.comparator = comparator;
106 }
107
108 private List<Component> getFocusTraversalCycle(Container aContainer) {
109 List<Component> cycle = new ArrayList<Component>();
110 enumerateAndSortCycle(aContainer, cycle);
111 return cycle;
112 }
113 private int getComponentIndex(List<Component> cycle, Component aComponent) {
114 int index;
115 try {
116 index = Collections.binarySearch(cycle, aComponent, comparator);
117 } catch (ClassCastException e) {
118 if (log.isLoggable(PlatformLogger.FINE)) {
119 log.fine("### During the binary search for " + aComponent + " the exception occured: ", e);
120 }
121 return -1;
122 }
123 if (index < 0) {
124 // Fix for 5070991.
125 // A workaround for a transitivity problem caused by ROW_TOLERANCE,
126 // because of that the component may be missed in the binary search.
127 // Try to search it again directly.
128 index = cycle.indexOf(aComponent);
129 }
130 return index;
131 }
132
133 private void enumerateAndSortCycle(Container focusCycleRoot, List<Component> cycle) {
134 if (focusCycleRoot.isShowing()) {
135 enumerateCycle(focusCycleRoot, cycle);
136 Collections.sort(cycle, comparator);
137 }
138 }
176 return ftp;
177 }
178
179 /*
180 * Checks if a new focus cycle takes place and returns a Component to traverse focus to.
181 * @param comp a possible focus cycle root or policy provider
182 * @param traversalDirection the direction of the traversal
183 * @return a Component to traverse focus to if {@code comp} is a root or provider
184 * and implicit down-cycle is set, otherwise {@code null}
185 */
186 private Component getComponentDownCycle(Component comp, int traversalDirection) {
187 Component retComp = null;
188
189 if (comp instanceof Container) {
190 Container cont = (Container)comp;
191
192 if (cont.isFocusCycleRoot()) {
193 if (getImplicitDownCycleTraversal()) {
194 retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont);
195
196 if (retComp != null && log.isLoggable(PlatformLogger.FINE)) {
197 log.fine("### Transfered focus down-cycle to " + retComp +
198 " in the focus cycle root " + cont);
199 }
200 } else {
201 return null;
202 }
203 } else if (cont.isFocusTraversalPolicyProvider()) {
204 retComp = (traversalDirection == FORWARD_TRAVERSAL ?
205 cont.getFocusTraversalPolicy().getDefaultComponent(cont) :
206 cont.getFocusTraversalPolicy().getLastComponent(cont));
207
208 if (retComp != null && log.isLoggable(PlatformLogger.FINE)) {
209 log.fine("### Transfered focus to " + retComp + " in the FTP provider " + cont);
210 }
211 }
212 }
213 return retComp;
214 }
215
216 /**
217 * Returns the Component that should receive the focus after aComponent.
218 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
219 * <p>
220 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
221 * cycle. That is, during normal focus traversal, the Component
222 * traversed after a focus cycle root will be the focus-cycle-root's
223 * default Component to focus. This behavior can be disabled using the
224 * <code>setImplicitDownCycleTraversal</code> method.
225 * <p>
226 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
227 * traversal policy provider</a>, the focus is always transferred down-cycle.
228 *
229 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
230 * @param aComponent a (possibly indirect) child of aContainer, or
231 * aContainer itself
232 * @return the Component that should receive the focus after aComponent, or
233 * null if no suitable Component can be found
234 * @throws IllegalArgumentException if aContainer is not a focus cycle
235 * root of aComponent or a focus traversal policy provider, or if either aContainer or
236 * aComponent is null
237 */
238 public Component getComponentAfter(Container aContainer, Component aComponent) {
239 if (log.isLoggable(PlatformLogger.FINE)) {
240 log.fine("### Searching in " + aContainer + " for component after " + aComponent);
241 }
242
243 if (aContainer == null || aComponent == null) {
244 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
245 }
246 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
247 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
248
249 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
250 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
251 }
252
253 // Before all the ckecks below we first see if it's an FTP provider or a focus cycle root.
254 // If it's the case just go down cycle (if it's set to "implicit").
255 Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL);
256 if (comp != null) {
257 return comp;
258 }
259
260 // See if the component is inside of policy provider.
261 Container provider = getTopmostProvider(aContainer, aComponent);
262 if (provider != null) {
263 if (log.isLoggable(PlatformLogger.FINE)) {
264 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
265 }
266
267 // FTP knows how to find component after the given. We don't.
268 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
269 Component afterComp = policy.getComponentAfter(provider, aComponent);
270
271 // Null result means that we overstepped the limit of the FTP's cycle.
272 // In that case we must quit the cycle, otherwise return the component found.
273 if (afterComp != null) {
274 if (log.isLoggable(PlatformLogger.FINE)) {
275 log.fine("### FTP returned " + afterComp);
276 }
277 return afterComp;
278 }
279 aComponent = provider;
280 }
281
282 List<Component> cycle = getFocusTraversalCycle(aContainer);
283
284 if (log.isLoggable(PlatformLogger.FINE)) {
285 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
286 }
287
288 int index = getComponentIndex(cycle, aComponent);
289
290 if (index < 0) {
291 if (log.isLoggable(PlatformLogger.FINE)) {
292 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
293 }
294 return getFirstComponent(aContainer);
295 }
296
297 for (index++; index < cycle.size(); index++) {
298 comp = cycle.get(index);
299 if (accept(comp)) {
300 return comp;
301 } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) {
302 return comp;
303 }
304 }
305
306 if (aContainer.isFocusCycleRoot()) {
307 this.cachedRoot = aContainer;
308 this.cachedCycle = cycle;
309
310 comp = getFirstComponent(aContainer);
311
336 * @return the Component that should receive the focus before aComponent,
337 * or null if no suitable Component can be found
338 * @throws IllegalArgumentException if aContainer is not a focus cycle
339 * root of aComponent or a focus traversal policy provider, or if either aContainer or
340 * aComponent is null
341 */
342 public Component getComponentBefore(Container aContainer, Component aComponent) {
343 if (aContainer == null || aComponent == null) {
344 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
345 }
346 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
347 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
348
349 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
350 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
351 }
352
353 // See if the component is inside of policy provider.
354 Container provider = getTopmostProvider(aContainer, aComponent);
355 if (provider != null) {
356 if (log.isLoggable(PlatformLogger.FINE)) {
357 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
358 }
359
360 // FTP knows how to find component after the given. We don't.
361 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
362 Component beforeComp = policy.getComponentBefore(provider, aComponent);
363
364 // Null result means that we overstepped the limit of the FTP's cycle.
365 // In that case we must quit the cycle, otherwise return the component found.
366 if (beforeComp != null) {
367 if (log.isLoggable(PlatformLogger.FINE)) {
368 log.fine("### FTP returned " + beforeComp);
369 }
370 return beforeComp;
371 }
372 aComponent = provider;
373
374 // If the provider is traversable it's returned.
375 if (accept(aComponent)) {
376 return aComponent;
377 }
378 }
379
380 List<Component> cycle = getFocusTraversalCycle(aContainer);
381
382 if (log.isLoggable(PlatformLogger.FINE)) {
383 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
384 }
385
386 int index = getComponentIndex(cycle, aComponent);
387
388 if (index < 0) {
389 if (log.isLoggable(PlatformLogger.FINE)) {
390 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
391 }
392 return getLastComponent(aContainer);
393 }
394
395 Component comp;
396 Component tryComp;
397
398 for (index--; index>=0; index--) {
399 comp = cycle.get(index);
400 if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) {
401 return tryComp;
402 } else if (accept(comp)) {
403 return comp;
404 }
405 }
406
407 if (aContainer.isFocusCycleRoot()) {
408 this.cachedRoot = aContainer;
409 this.cachedCycle = cycle;
415
416 return comp;
417 }
418 return null;
419 }
420
421 /**
422 * Returns the first Component in the traversal cycle. This method is used
423 * to determine the next Component to focus when traversal wraps in the
424 * forward direction.
425 *
426 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
427 * first Component is to be returned
428 * @return the first Component in the traversal cycle of aContainer,
429 * or null if no suitable Component can be found
430 * @throws IllegalArgumentException if aContainer is null
431 */
432 public Component getFirstComponent(Container aContainer) {
433 List<Component> cycle;
434
435 if (log.isLoggable(PlatformLogger.FINE)) {
436 log.fine("### Getting first component in " + aContainer);
437 }
438 if (aContainer == null) {
439 throw new IllegalArgumentException("aContainer cannot be null");
440 }
441
442 if (this.cachedRoot == aContainer) {
443 cycle = this.cachedCycle;
444 } else {
445 cycle = getFocusTraversalCycle(aContainer);
446 }
447
448 if (cycle.size() == 0) {
449 if (log.isLoggable(PlatformLogger.FINE)) {
450 log.fine("### Cycle is empty");
451 }
452 return null;
453 }
454 if (log.isLoggable(PlatformLogger.FINE)) {
455 log.fine("### Cycle is " + cycle);
456 }
457
458 for (Component comp : cycle) {
459 if (accept(comp)) {
460 return comp;
461 } else if (comp != aContainer &&
462 (comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null)
463 {
464 return comp;
465 }
466 }
467 return null;
468 }
469
470 /**
471 * Returns the last Component in the traversal cycle. This method is used
472 * to determine the next Component to focus when traversal wraps in the
473 * reverse direction.
474 *
475 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
476 * last Component is to be returned
477 * @return the last Component in the traversal cycle of aContainer,
478 * or null if no suitable Component can be found
479 * @throws IllegalArgumentException if aContainer is null
480 */
481 public Component getLastComponent(Container aContainer) {
482 List<Component> cycle;
483 if (log.isLoggable(PlatformLogger.FINE)) {
484 log.fine("### Getting last component in " + aContainer);
485 }
486
487 if (aContainer == null) {
488 throw new IllegalArgumentException("aContainer cannot be null");
489 }
490
491 if (this.cachedRoot == aContainer) {
492 cycle = this.cachedCycle;
493 } else {
494 cycle = getFocusTraversalCycle(aContainer);
495 }
496
497 if (cycle.size() == 0) {
498 if (log.isLoggable(PlatformLogger.FINE)) {
499 log.fine("### Cycle is empty");
500 }
501 return null;
502 }
503 if (log.isLoggable(PlatformLogger.FINE)) {
504 log.fine("### Cycle is " + cycle);
505 }
506
507 for (int i= cycle.size() - 1; i >= 0; i--) {
508 Component comp = cycle.get(i);
509 if (accept(comp)) {
510 return comp;
511 } else if (comp instanceof Container && comp != aContainer) {
512 Container cont = (Container)comp;
513 if (cont.isFocusTraversalPolicyProvider()) {
514 return cont.getFocusTraversalPolicy().getLastComponent(cont);
515 }
516 }
517 }
518 return null;
519 }
520
521 /**
522 * Returns the default Component to focus. This Component will be the first
523 * to receive focus when traversing down into a new focus traversal cycle
|
98 protected SortingFocusTraversalPolicy() {
99 }
100
101 /**
102 * Constructs a SortingFocusTraversalPolicy with the specified Comparator.
103 */
104 public SortingFocusTraversalPolicy(Comparator<? super Component> comparator) {
105 this.comparator = comparator;
106 }
107
108 private List<Component> getFocusTraversalCycle(Container aContainer) {
109 List<Component> cycle = new ArrayList<Component>();
110 enumerateAndSortCycle(aContainer, cycle);
111 return cycle;
112 }
113 private int getComponentIndex(List<Component> cycle, Component aComponent) {
114 int index;
115 try {
116 index = Collections.binarySearch(cycle, aComponent, comparator);
117 } catch (ClassCastException e) {
118 if (log.isLoggable(PlatformLogger.Level.FINE)) {
119 log.fine("### During the binary search for " + aComponent + " the exception occured: ", e);
120 }
121 return -1;
122 }
123 if (index < 0) {
124 // Fix for 5070991.
125 // A workaround for a transitivity problem caused by ROW_TOLERANCE,
126 // because of that the component may be missed in the binary search.
127 // Try to search it again directly.
128 index = cycle.indexOf(aComponent);
129 }
130 return index;
131 }
132
133 private void enumerateAndSortCycle(Container focusCycleRoot, List<Component> cycle) {
134 if (focusCycleRoot.isShowing()) {
135 enumerateCycle(focusCycleRoot, cycle);
136 Collections.sort(cycle, comparator);
137 }
138 }
176 return ftp;
177 }
178
179 /*
180 * Checks if a new focus cycle takes place and returns a Component to traverse focus to.
181 * @param comp a possible focus cycle root or policy provider
182 * @param traversalDirection the direction of the traversal
183 * @return a Component to traverse focus to if {@code comp} is a root or provider
184 * and implicit down-cycle is set, otherwise {@code null}
185 */
186 private Component getComponentDownCycle(Component comp, int traversalDirection) {
187 Component retComp = null;
188
189 if (comp instanceof Container) {
190 Container cont = (Container)comp;
191
192 if (cont.isFocusCycleRoot()) {
193 if (getImplicitDownCycleTraversal()) {
194 retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont);
195
196 if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) {
197 log.fine("### Transfered focus down-cycle to " + retComp +
198 " in the focus cycle root " + cont);
199 }
200 } else {
201 return null;
202 }
203 } else if (cont.isFocusTraversalPolicyProvider()) {
204 retComp = (traversalDirection == FORWARD_TRAVERSAL ?
205 cont.getFocusTraversalPolicy().getDefaultComponent(cont) :
206 cont.getFocusTraversalPolicy().getLastComponent(cont));
207
208 if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) {
209 log.fine("### Transfered focus to " + retComp + " in the FTP provider " + cont);
210 }
211 }
212 }
213 return retComp;
214 }
215
216 /**
217 * Returns the Component that should receive the focus after aComponent.
218 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
219 * <p>
220 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
221 * cycle. That is, during normal focus traversal, the Component
222 * traversed after a focus cycle root will be the focus-cycle-root's
223 * default Component to focus. This behavior can be disabled using the
224 * <code>setImplicitDownCycleTraversal</code> method.
225 * <p>
226 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
227 * traversal policy provider</a>, the focus is always transferred down-cycle.
228 *
229 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
230 * @param aComponent a (possibly indirect) child of aContainer, or
231 * aContainer itself
232 * @return the Component that should receive the focus after aComponent, or
233 * null if no suitable Component can be found
234 * @throws IllegalArgumentException if aContainer is not a focus cycle
235 * root of aComponent or a focus traversal policy provider, or if either aContainer or
236 * aComponent is null
237 */
238 public Component getComponentAfter(Container aContainer, Component aComponent) {
239 if (log.isLoggable(PlatformLogger.Level.FINE)) {
240 log.fine("### Searching in " + aContainer + " for component after " + aComponent);
241 }
242
243 if (aContainer == null || aComponent == null) {
244 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
245 }
246 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
247 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
248
249 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
250 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
251 }
252
253 // Before all the ckecks below we first see if it's an FTP provider or a focus cycle root.
254 // If it's the case just go down cycle (if it's set to "implicit").
255 Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL);
256 if (comp != null) {
257 return comp;
258 }
259
260 // See if the component is inside of policy provider.
261 Container provider = getTopmostProvider(aContainer, aComponent);
262 if (provider != null) {
263 if (log.isLoggable(PlatformLogger.Level.FINE)) {
264 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
265 }
266
267 // FTP knows how to find component after the given. We don't.
268 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
269 Component afterComp = policy.getComponentAfter(provider, aComponent);
270
271 // Null result means that we overstepped the limit of the FTP's cycle.
272 // In that case we must quit the cycle, otherwise return the component found.
273 if (afterComp != null) {
274 if (log.isLoggable(PlatformLogger.Level.FINE)) {
275 log.fine("### FTP returned " + afterComp);
276 }
277 return afterComp;
278 }
279 aComponent = provider;
280 }
281
282 List<Component> cycle = getFocusTraversalCycle(aContainer);
283
284 if (log.isLoggable(PlatformLogger.Level.FINE)) {
285 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
286 }
287
288 int index = getComponentIndex(cycle, aComponent);
289
290 if (index < 0) {
291 if (log.isLoggable(PlatformLogger.Level.FINE)) {
292 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
293 }
294 return getFirstComponent(aContainer);
295 }
296
297 for (index++; index < cycle.size(); index++) {
298 comp = cycle.get(index);
299 if (accept(comp)) {
300 return comp;
301 } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) {
302 return comp;
303 }
304 }
305
306 if (aContainer.isFocusCycleRoot()) {
307 this.cachedRoot = aContainer;
308 this.cachedCycle = cycle;
309
310 comp = getFirstComponent(aContainer);
311
336 * @return the Component that should receive the focus before aComponent,
337 * or null if no suitable Component can be found
338 * @throws IllegalArgumentException if aContainer is not a focus cycle
339 * root of aComponent or a focus traversal policy provider, or if either aContainer or
340 * aComponent is null
341 */
342 public Component getComponentBefore(Container aContainer, Component aComponent) {
343 if (aContainer == null || aComponent == null) {
344 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
345 }
346 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
347 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
348
349 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
350 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
351 }
352
353 // See if the component is inside of policy provider.
354 Container provider = getTopmostProvider(aContainer, aComponent);
355 if (provider != null) {
356 if (log.isLoggable(PlatformLogger.Level.FINE)) {
357 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
358 }
359
360 // FTP knows how to find component after the given. We don't.
361 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
362 Component beforeComp = policy.getComponentBefore(provider, aComponent);
363
364 // Null result means that we overstepped the limit of the FTP's cycle.
365 // In that case we must quit the cycle, otherwise return the component found.
366 if (beforeComp != null) {
367 if (log.isLoggable(PlatformLogger.Level.FINE)) {
368 log.fine("### FTP returned " + beforeComp);
369 }
370 return beforeComp;
371 }
372 aComponent = provider;
373
374 // If the provider is traversable it's returned.
375 if (accept(aComponent)) {
376 return aComponent;
377 }
378 }
379
380 List<Component> cycle = getFocusTraversalCycle(aContainer);
381
382 if (log.isLoggable(PlatformLogger.Level.FINE)) {
383 log.fine("### Cycle is " + cycle + ", component is " + aComponent);
384 }
385
386 int index = getComponentIndex(cycle, aComponent);
387
388 if (index < 0) {
389 if (log.isLoggable(PlatformLogger.Level.FINE)) {
390 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
391 }
392 return getLastComponent(aContainer);
393 }
394
395 Component comp;
396 Component tryComp;
397
398 for (index--; index>=0; index--) {
399 comp = cycle.get(index);
400 if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) {
401 return tryComp;
402 } else if (accept(comp)) {
403 return comp;
404 }
405 }
406
407 if (aContainer.isFocusCycleRoot()) {
408 this.cachedRoot = aContainer;
409 this.cachedCycle = cycle;
415
416 return comp;
417 }
418 return null;
419 }
420
421 /**
422 * Returns the first Component in the traversal cycle. This method is used
423 * to determine the next Component to focus when traversal wraps in the
424 * forward direction.
425 *
426 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
427 * first Component is to be returned
428 * @return the first Component in the traversal cycle of aContainer,
429 * or null if no suitable Component can be found
430 * @throws IllegalArgumentException if aContainer is null
431 */
432 public Component getFirstComponent(Container aContainer) {
433 List<Component> cycle;
434
435 if (log.isLoggable(PlatformLogger.Level.FINE)) {
436 log.fine("### Getting first component in " + aContainer);
437 }
438 if (aContainer == null) {
439 throw new IllegalArgumentException("aContainer cannot be null");
440 }
441
442 if (this.cachedRoot == aContainer) {
443 cycle = this.cachedCycle;
444 } else {
445 cycle = getFocusTraversalCycle(aContainer);
446 }
447
448 if (cycle.size() == 0) {
449 if (log.isLoggable(PlatformLogger.Level.FINE)) {
450 log.fine("### Cycle is empty");
451 }
452 return null;
453 }
454 if (log.isLoggable(PlatformLogger.Level.FINE)) {
455 log.fine("### Cycle is " + cycle);
456 }
457
458 for (Component comp : cycle) {
459 if (accept(comp)) {
460 return comp;
461 } else if (comp != aContainer &&
462 (comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null)
463 {
464 return comp;
465 }
466 }
467 return null;
468 }
469
470 /**
471 * Returns the last Component in the traversal cycle. This method is used
472 * to determine the next Component to focus when traversal wraps in the
473 * reverse direction.
474 *
475 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
476 * last Component is to be returned
477 * @return the last Component in the traversal cycle of aContainer,
478 * or null if no suitable Component can be found
479 * @throws IllegalArgumentException if aContainer is null
480 */
481 public Component getLastComponent(Container aContainer) {
482 List<Component> cycle;
483 if (log.isLoggable(PlatformLogger.Level.FINE)) {
484 log.fine("### Getting last component in " + aContainer);
485 }
486
487 if (aContainer == null) {
488 throw new IllegalArgumentException("aContainer cannot be null");
489 }
490
491 if (this.cachedRoot == aContainer) {
492 cycle = this.cachedCycle;
493 } else {
494 cycle = getFocusTraversalCycle(aContainer);
495 }
496
497 if (cycle.size() == 0) {
498 if (log.isLoggable(PlatformLogger.Level.FINE)) {
499 log.fine("### Cycle is empty");
500 }
501 return null;
502 }
503 if (log.isLoggable(PlatformLogger.Level.FINE)) {
504 log.fine("### Cycle is " + cycle);
505 }
506
507 for (int i= cycle.size() - 1; i >= 0; i--) {
508 Component comp = cycle.get(i);
509 if (accept(comp)) {
510 return comp;
511 } else if (comp instanceof Container && comp != aContainer) {
512 Container cont = (Container)comp;
513 if (cont.isFocusTraversalPolicyProvider()) {
514 return cont.getFocusTraversalPolicy().getLastComponent(cont);
515 }
516 }
517 }
518 return null;
519 }
520
521 /**
522 * Returns the default Component to focus. This Component will be the first
523 * to receive focus when traversing down into a new focus traversal cycle
|