1 /*
2 * Copyright 2000-2007 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any 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 java.util.logging;
33
34 /**
35 * A FocusTraversalPolicy that determines traversal order by sorting the
36 * Components of a focus traversal cycle based on a given Comparator. Portions
37 * of the Component hierarchy that are not visible and displayable will not be
38 * included.
39 * <p>
40 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
41 * cycle. That is, during normal focus traversal, the Component
42 * traversed after a focus cycle root will be the focus-cycle-root's default
43 * Component to focus. This behavior can be disabled using the
44 * <code>setImplicitDownCycleTraversal</code> method.
45 * <p>
46 * By default, methods of this class with return a Component only if it is
47 * visible, displayable, enabled, and focusable. Subclasses can modify this
48 * behavior by overriding the <code>accept</code> method.
49 * <p>
50 * This policy takes into account <a
51 * href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal
52 * policy providers</a>. When searching for first/last/next/previous Component,
53 * if a focus traversal policy provider is encountered, its focus traversal
54 * policy is used to perform the search operation.
55 *
56 * @author David Mendenhall
57 *
58 * @see java.util.Comparator
59 * @since 1.4
60 */
61 public class SortingFocusTraversalPolicy
62 extends InternalFrameFocusTraversalPolicy
63 {
64 private Comparator<? super Component> comparator;
65 private boolean implicitDownCycleTraversal = true;
66
67 private Logger log = Logger.getLogger("javax.swing.SortingFocusTraversalPolicy");
68
69 /**
70 * Used by getComponentAfter and getComponentBefore for efficiency. In
71 * order to maintain compliance with the specification of
72 * FocusTraversalPolicy, if traversal wraps, we should invoke
73 * getFirstComponent or getLastComponent. These methods may be overriden in
74 * subclasses to behave in a non-generic way. However, in the generic case,
75 * these methods will simply return the first or last Components of the
76 * sorted list, respectively. Since getComponentAfter and
77 * getComponentBefore have already built the sorted list before determining
78 * that they need to invoke getFirstComponent or getLastComponent, the
79 * sorted list should be reused if possible.
80 */
81 transient private Container cachedRoot;
82 transient private List cachedCycle;
83
84 // Delegate our fitness test to ContainerOrder so that we only have to
85 // code the algorithm once.
86 private static final SwingContainerOrderFocusTraversalPolicy
87 fitnessTestPolicy = new SwingContainerOrderFocusTraversalPolicy();
88
89 final private int FORWARD_TRAVERSAL = 0;
90 final private int BACKWARD_TRAVERSAL = 1;
91
92 /**
93 * Constructs a SortingFocusTraversalPolicy without a Comparator.
94 * Subclasses must set the Comparator using <code>setComparator</code>
95 * before installing this FocusTraversalPolicy on a focus cycle root or
96 * KeyboardFocusManager.
97 */
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 = 0;
115 try {
116 index = Collections.binarySearch(cycle, aComponent, comparator);
117 } catch (ClassCastException e) {
118 if (log.isLoggable(Level.FINE)) {
119 log.log(Level.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 cycle) {
134 if (focusCycleRoot.isShowing()) {
135 enumerateCycle(focusCycleRoot, cycle);
136 Collections.sort(cycle, comparator);
137 }
138 }
139
140 private void enumerateCycle(Container container, List cycle) {
141 if (!(container.isVisible() && container.isDisplayable())) {
142 return;
143 }
144
145 cycle.add(container);
146
147 Component[] components = container.getComponents();
148 for (int i = 0; i < components.length; i++) {
149 Component comp = components[i];
150 if (comp instanceof Container) {
151 Container cont = (Container)comp;
152
153 if (!cont.isFocusCycleRoot() &&
154 !cont.isFocusTraversalPolicyProvider() &&
155 !((cont instanceof JComponent) && ((JComponent)cont).isManagingFocus()))
156 {
157 enumerateCycle(cont, cycle);
158 continue;
159 }
160 }
161 cycle.add(comp);
162 }
163 }
164
165 Container getTopmostProvider(Container focusCycleRoot, Component aComponent) {
166 Container aCont = aComponent.getParent();
167 Container ftp = null;
168 while (aCont != focusCycleRoot && aCont != null) {
169 if (aCont.isFocusTraversalPolicyProvider()) {
170 ftp = aCont;
171 }
172 aCont = aCont.getParent();
173 }
174 if (aCont == null) {
175 return null;
176 }
177 return ftp;
178 }
179
180 /*
181 * Checks if a new focus cycle takes place and returns a Component to traverse focus to.
182 * @param comp a possible focus cycle root or policy provider
183 * @param traversalDirection the direction of the traversal
184 * @return a Component to traverse focus to if {@code comp} is a root or provider
185 * and implicit down-cycle is set, otherwise {@code null}
186 */
187 private Component getComponentDownCycle(Component comp, int traversalDirection) {
188 Component retComp = null;
189
190 if (comp instanceof Container) {
191 Container cont = (Container)comp;
192
193 if (cont.isFocusCycleRoot()) {
194 if (getImplicitDownCycleTraversal()) {
195 retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont);
196
197 if (retComp != null && log.isLoggable(Level.FINE)) {
198 log.fine("### Transfered focus down-cycle to " + retComp +
199 " in the focus cycle root " + cont);
200 }
201 } else {
202 return null;
203 }
204 } else if (cont.isFocusTraversalPolicyProvider()) {
205 retComp = (traversalDirection == FORWARD_TRAVERSAL ?
206 cont.getFocusTraversalPolicy().getDefaultComponent(cont) :
207 cont.getFocusTraversalPolicy().getLastComponent(cont));
208
209 if (retComp != null && log.isLoggable(Level.FINE)) {
210 log.fine("### Transfered focus to " + retComp + " in the FTP provider " + cont);
211 }
212 }
213 }
214 return retComp;
215 }
216
217 /**
218 * Returns the Component that should receive the focus after aComponent.
219 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
220 * <p>
221 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
222 * cycle. That is, during normal focus traversal, the Component
223 * traversed after a focus cycle root will be the focus-cycle-root's
224 * default Component to focus. This behavior can be disabled using the
225 * <code>setImplicitDownCycleTraversal</code> method.
226 * <p>
227 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
228 * traversal policy provider</a>, the focus is always transferred down-cycle.
229 *
230 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
231 * @param aComponent a (possibly indirect) child of aContainer, or
232 * aContainer itself
233 * @return the Component that should receive the focus after aComponent, or
234 * null if no suitable Component can be found
235 * @throws IllegalArgumentException if aContainer is not a focus cycle
236 * root of aComponent or a focus traversal policy provider, or if either aContainer or
237 * aComponent is null
238 */
239 public Component getComponentAfter(Container aContainer, Component aComponent) {
240 if (log.isLoggable(Level.FINE)) {
241 log.fine("### Searching in " + aContainer + " for component after " + aComponent);
242 }
243
244 if (aContainer == null || aComponent == null) {
245 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
246 }
247 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
248 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
249
250 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
251 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
252 }
253
254 // Before all the ckecks below we first see if it's an FTP provider or a focus cycle root.
255 // If it's the case just go down cycle (if it's set to "implicit").
256 Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL);
257 if (comp != null) {
258 return comp;
259 }
260
261 // See if the component is inside of policy provider.
262 Container provider = getTopmostProvider(aContainer, aComponent);
263 if (provider != null) {
264 if (log.isLoggable(Level.FINE)) {
265 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
266 }
267
268 // FTP knows how to find component after the given. We don't.
269 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
270 Component afterComp = policy.getComponentAfter(provider, aComponent);
271
272 // Null result means that we overstepped the limit of the FTP's cycle.
273 // In that case we must quit the cycle, otherwise return the component found.
274 if (afterComp != null) {
275 if (log.isLoggable(Level.FINE)) log.fine("### FTP returned " + afterComp);
276 return afterComp;
277 }
278 aComponent = provider;
279 }
280
281 List<Component> cycle = getFocusTraversalCycle(aContainer);
282
283 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent);
284
285 int index = getComponentIndex(cycle, aComponent);
286
287 if (index < 0) {
288 if (log.isLoggable(Level.FINE)) {
289 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
290 }
291 return getFirstComponent(aContainer);
292 }
293
294 for (index++; index < cycle.size(); index++) {
295 comp = cycle.get(index);
296 if (accept(comp)) {
297 return comp;
298 } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) {
299 return comp;
300 }
301 }
302
303 if (aContainer.isFocusCycleRoot()) {
304 this.cachedRoot = aContainer;
305 this.cachedCycle = cycle;
306
307 comp = getFirstComponent(aContainer);
308
309 this.cachedRoot = null;
310 this.cachedCycle = null;
311
312 return comp;
313 }
314 return null;
315 }
316
317 /**
318 * Returns the Component that should receive the focus before aComponent.
319 * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
320 * <p>
321 * By default, SortingFocusTraversalPolicy implicitly transfers focus down-
322 * cycle. That is, during normal focus traversal, the Component
323 * traversed after a focus cycle root will be the focus-cycle-root's
324 * default Component to focus. This behavior can be disabled using the
325 * <code>setImplicitDownCycleTraversal</code> method.
326 * <p>
327 * If aContainer is <a href="../../java/awt/doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
328 * traversal policy provider</a>, the focus is always transferred down-cycle.
329 *
330 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
331 * @param aComponent a (possibly indirect) child of aContainer, or
332 * aContainer itself
333 * @return the Component that should receive the focus before aComponent,
334 * or null if no suitable Component can be found
335 * @throws IllegalArgumentException if aContainer is not a focus cycle
336 * root of aComponent or a focus traversal policy provider, or if either aContainer or
337 * aComponent is null
338 */
339 public Component getComponentBefore(Container aContainer, Component aComponent) {
340 if (aContainer == null || aComponent == null) {
341 throw new IllegalArgumentException("aContainer and aComponent cannot be null");
342 }
343 if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
344 throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
345
346 } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
347 throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
348 }
349
350 // See if the component is inside of policy provider.
351 Container provider = getTopmostProvider(aContainer, aComponent);
352 if (provider != null) {
353 if (log.isLoggable(Level.FINE)) {
354 log.fine("### Asking FTP " + provider + " for component after " + aComponent);
355 }
356
357 // FTP knows how to find component after the given. We don't.
358 FocusTraversalPolicy policy = provider.getFocusTraversalPolicy();
359 Component beforeComp = policy.getComponentBefore(provider, aComponent);
360
361 // Null result means that we overstepped the limit of the FTP's cycle.
362 // In that case we must quit the cycle, otherwise return the component found.
363 if (beforeComp != null) {
364 if (log.isLoggable(Level.FINE)) log.fine("### FTP returned " + beforeComp);
365 return beforeComp;
366 }
367 aComponent = provider;
368
369 // If the provider is traversable it's returned.
370 if (accept(aComponent)) {
371 return aComponent;
372 }
373 }
374
375 List<Component> cycle = getFocusTraversalCycle(aContainer);
376
377 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent);
378
379 int index = getComponentIndex(cycle, aComponent);
380
381 if (index < 0) {
382 if (log.isLoggable(Level.FINE)) {
383 log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer);
384 }
385 return getLastComponent(aContainer);
386 }
387
388 Component comp = null;
389 Component tryComp = null;
390
391 for (index--; index>=0; index--) {
392 comp = cycle.get(index);
393 if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) {
394 return tryComp;
395 } else if (accept(comp)) {
396 return comp;
397 }
398 }
399
400 if (aContainer.isFocusCycleRoot()) {
401 this.cachedRoot = aContainer;
402 this.cachedCycle = cycle;
403
404 comp = getLastComponent(aContainer);
405
406 this.cachedRoot = null;
407 this.cachedCycle = null;
408
409 return comp;
410 }
411 return null;
412 }
413
414 /**
415 * Returns the first Component in the traversal cycle. This method is used
416 * to determine the next Component to focus when traversal wraps in the
417 * forward direction.
418 *
419 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
420 * first Component is to be returned
421 * @return the first Component in the traversal cycle of aContainer,
422 * or null if no suitable Component can be found
423 * @throws IllegalArgumentException if aContainer is null
424 */
425 public Component getFirstComponent(Container aContainer) {
426 List<Component> cycle;
427
428 if (log.isLoggable(Level.FINE)) log.fine("### Getting first component in " + aContainer);
429 if (aContainer == null) {
430 throw new IllegalArgumentException("aContainer cannot be null");
431 }
432
433 if (this.cachedRoot == aContainer) {
434 cycle = this.cachedCycle;
435 } else {
436 cycle = getFocusTraversalCycle(aContainer);
437 }
438
439 if (cycle.size() == 0) {
440 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty");
441 return null;
442 }
443 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle);
444
445 for (int i = 0; i < cycle.size(); i++) {
446 Component comp = cycle.get(i);
447 if (accept(comp)) {
448 return comp;
449 } else if (comp instanceof Container && comp != aContainer) {
450 Container cont = (Container)comp;
451 if (cont.isFocusTraversalPolicyProvider()) {
452 return cont.getFocusTraversalPolicy().getDefaultComponent(cont);
453 }
454 }
455 }
456 return null;
457 }
458
459 /**
460 * Returns the last Component in the traversal cycle. This method is used
461 * to determine the next Component to focus when traversal wraps in the
462 * reverse direction.
463 *
464 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
465 * last Component is to be returned
466 * @return the last Component in the traversal cycle of aContainer,
467 * or null if no suitable Component can be found
468 * @throws IllegalArgumentException if aContainer is null
469 */
470 public Component getLastComponent(Container aContainer) {
471 List<Component> cycle;
472 if (log.isLoggable(Level.FINE)) log.fine("### Getting last component in " + aContainer);
473
474 if (aContainer == null) {
475 throw new IllegalArgumentException("aContainer cannot be null");
476 }
477
478 if (this.cachedRoot == aContainer) {
479 cycle = this.cachedCycle;
480 } else {
481 cycle = getFocusTraversalCycle(aContainer);
482 }
483
484 if (cycle.size() == 0) {
485 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty");
486 return null;
487 }
488 if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle);
489
490 for (int i= cycle.size() - 1; i >= 0; i--) {
491 Component comp = cycle.get(i);
492 if (accept(comp)) {
493 return comp;
494 } else if (comp instanceof Container && comp != aContainer) {
495 Container cont = (Container)comp;
496 if (cont.isFocusTraversalPolicyProvider()) {
497 return cont.getFocusTraversalPolicy().getLastComponent(cont);
498 }
499 }
500 }
501 return null;
502 }
503
504 /**
505 * Returns the default Component to focus. This Component will be the first
506 * to receive focus when traversing down into a new focus traversal cycle
507 * rooted at aContainer. The default implementation of this method
508 * returns the same Component as <code>getFirstComponent</code>.
509 *
510 * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
511 * default Component is to be returned
512 * @return the default Component in the traversal cycle of aContainer,
513 * or null if no suitable Component can be found
514 * @see #getFirstComponent
515 * @throws IllegalArgumentException if aContainer is null
516 */
517 public Component getDefaultComponent(Container aContainer) {
518 return getFirstComponent(aContainer);
519 }
520
521 /**
522 * Sets whether this SortingFocusTraversalPolicy transfers focus down-cycle
523 * implicitly. If <code>true</code>, during normal focus traversal,
524 * the Component traversed after a focus cycle root will be the focus-
525 * cycle-root's default Component to focus. If <code>false</code>, the
526 * next Component in the focus traversal cycle rooted at the specified
527 * focus cycle root will be traversed instead. The default value for this
528 * property is <code>true</code>.
529 *
530 * @param implicitDownCycleTraversal whether this
531 * SortingFocusTraversalPolicy transfers focus down-cycle implicitly
532 * @see #getImplicitDownCycleTraversal
533 * @see #getFirstComponent
534 */
535 public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal) {
536 this.implicitDownCycleTraversal = implicitDownCycleTraversal;
537 }
538
539 /**
540 * Returns whether this SortingFocusTraversalPolicy transfers focus down-
541 * cycle implicitly. If <code>true</code>, during normal focus
542 * traversal, the Component traversed after a focus cycle root will be the
543 * focus-cycle-root's default Component to focus. If <code>false</code>,
544 * the next Component in the focus traversal cycle rooted at the specified
545 * focus cycle root will be traversed instead.
546 *
547 * @return whether this SortingFocusTraversalPolicy transfers focus down-
548 * cycle implicitly
549 * @see #setImplicitDownCycleTraversal
550 * @see #getFirstComponent
551 */
552 public boolean getImplicitDownCycleTraversal() {
553 return implicitDownCycleTraversal;
554 }
555
556 /**
557 * Sets the Comparator which will be used to sort the Components in a
558 * focus traversal cycle.
559 *
560 * @param comparator the Comparator which will be used for sorting
561 */
562 protected void setComparator(Comparator<? super Component> comparator) {
563 this.comparator = comparator;
564 }
565
566 /**
567 * Returns the Comparator which will be used to sort the Components in a
568 * focus traversal cycle.
569 *
570 * @return the Comparator which will be used for sorting
571 */
572 protected Comparator<? super Component> getComparator() {
573 return comparator;
574 }
575
576 /**
577 * Determines whether a Component is an acceptable choice as the new
578 * focus owner. By default, this method will accept a Component if and
579 * only if it is visible, displayable, enabled, and focusable.
580 *
581 * @param aComponent the Component whose fitness as a focus owner is to
582 * be tested
583 * @return <code>true</code> if aComponent is visible, displayable,
584 * enabled, and focusable; <code>false</code> otherwise
585 */
586 protected boolean accept(Component aComponent) {
587 return fitnessTestPolicy.accept(aComponent);
588 }
589 }
590
591 // Create our own subclass and change accept to public so that we can call
592 // accept.
593 class SwingContainerOrderFocusTraversalPolicy
594 extends java.awt.ContainerOrderFocusTraversalPolicy
595 {
596 public boolean accept(Component aComponent) {
597 return super.accept(aComponent);
598 }
599 }
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