API Overview API Index Package Overview Direct link to this page
JDK 1.6
  java.awt. ContainerOrderFocusTraversalPolicy View Javadoc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483

/*
 * @(#)ContainerOrderFocusTraversalPolicy.java	1.9 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package java.awt;

import java.util.logging.*;

/**
 * A FocusTraversalPolicy that determines traversal order based on the order
 * of child Components in a Container. From a particular focus cycle root, the
 * policy makes a pre-order traversal of the Component hierarchy, and traverses
 * a Container's children according to the ordering of the array returned by
 * <code>Container.getComponents()</code>. Portions of the hierarchy that are
 * not visible and displayable will not be searched.
 * <p>
 * By default, ContainerOrderFocusTraversalPolicy implicitly transfers focus
 * down-cycle. That is, during normal forward focus traversal, the Component
 * traversed after a focus cycle root will be the focus-cycle-root's default
 * Component to focus. This behavior can be disabled using the
 * <code>setImplicitDownCycleTraversal</code> method.
 * <p>
 * By default, methods of this class with return a Component only if it is
 * visible, displayable, enabled, and focusable. Subclasses can modify this
 * behavior by overriding the <code>accept</code> method.
 * <p>
 * This policy takes into account <a
 * href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal
 * policy providers</a>.  When searching for first/last/next/previous Component,
 * if a focus traversal policy provider is encountered, its focus traversal
 * policy is used to perform the search operation.
 *
 * @author David Mendenhall
 * @version 1.9, 11/17/05
 *
 * @see Container#getComponents
 * @since 1.4
 */
public class ContainerOrderFocusTraversalPolicy extends FocusTraversalPolicy
    implements java.io.Serializable
{
    private static final MutableBoolean found = new MutableBoolean();

    private static final Logger log = Logger.getLogger("java.awt.ContainerOrderFocusTraversalPolicy");

    /*
     * JDK 1.4 serialVersionUID 
     */
    private static final long serialVersionUID = 486933713763926351L;

    private boolean implicitDownCycleTraversal = true;

    /**
     * Returns the Component that should receive the focus after aComponent.
     * aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
     * <p>
     * By default, ContainerOrderFocusTraversalPolicy implicitly transfers
     * focus down-cycle. That is, during normal forward focus traversal, the
     * Component traversed after a focus cycle root will be the focus-cycle-
     * root's default Component to focus. This behavior can be disabled using
     * the <code>setImplicitDownCycleTraversal</code> method.
     * <p>
     * If aContainer is <a href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
     * traversal policy provider</a>, the focus is always transferred down-cycle.
     *
     * @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
     * @param aComponent a (possibly indirect) child of aContainer, or
     *        aContainer itself
     * @return the Component that should receive the focus after aComponent, or
     *         null if no suitable Component can be found
     * @throws IllegalArgumentException if aContainer is not a focus cycle
     *         root of aComponent or focus traversal policy provider, or if either aContainer or
     *         aComponent is null
     */
    public Component getComponentAfter(Container aContainer,
                                       Component aComponent) {
        if (log.isLoggable(Level.FINE)) log.fine("Looking for next component in " + aContainer  + " for " + aComponent);
        if (aContainer == null || aComponent == null) {
            throw new IllegalArgumentException("aContainer and aComponent cannot be null");
        }
        if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
            throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
        } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
            throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
        }

        synchronized(aContainer.getTreeLock()) {
            found.value = false;
            Component retval = getComponentAfter(aContainer, aComponent,
                                                 found);
            if (retval != null) {
                if (log.isLoggable(Level.FINE)) log.fine("After component is " + retval);
                return retval;
            } else if (found.value) {
                if (log.isLoggable(Level.FINE)) log.fine("Didn't find next component in " + aContainer + " - falling back to the first ");
                return getFirstComponent(aContainer);
            } else {
                if (log.isLoggable(Level.FINE)) log.fine("After component is null");
                return null;
            }
        }
    }

    private Component getComponentAfter(Container aContainer,
                                        Component aComponent,
                                        MutableBoolean found) {
        if (!(aContainer.isVisible() && aContainer.isDisplayable())) {
	    return null;
	}

        if (found.value) {
            if (accept(aContainer)) {
                return aContainer;
            }
        } else if (aContainer == aComponent) {
            found.value = true;
        }

        for (int i = 0; i < aContainer.ncomponents; i++) {
            Component comp = aContainer.component[i];
            if ((comp instanceof Container) &&
                !((Container)comp).isFocusCycleRoot()) {
                Component retval = null;
                if (((Container)comp).isFocusTraversalPolicyProvider()) {
                    if (log.isLoggable(Level.FINE)) log.fine("Entering FTP " + comp);
                    Container cont = (Container) comp;
                    FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
                    if (log.isLoggable(Level.FINE)) log.fine("FTP contains " + aComponent + ": " + cont.isAncestorOf(aComponent));
                    if (found.value) {
                        retval = policy.getDefaultComponent(cont);
                        if (log.isLoggable(Level.FINE)) log.fine("Used FTP for getting default component: " + retval);
                    } else {
                        found.value = cont.isAncestorOf(aComponent);                    
                        if (found.value)  {
                            if (aComponent == policy.getLastComponent(cont)) {
                            // Reached last component, going to wrap - should switch to next provider
                            retval = null;
                            } else {
                                retval = policy.getComponentAfter(cont, aComponent);
                                if (log.isLoggable(Level.FINE)) log.fine("FTP found next for the component : " + retval);
                            }
                        }
                    }
                } else {
                    retval = getComponentAfter((Container)comp,
                                                     aComponent,
                                                     found);
                }
                if (retval != null) {
                    return retval;
                }
            } else if (found.value) {
                if (accept(comp)) {
                    return comp;
                }
            } else if (comp == aComponent) {
                found.value = true;
            }

	    if (found.value &&
		getImplicitDownCycleTraversal() &&
		(comp instanceof Container) &&
		((Container)comp).isFocusCycleRoot())
	    {
		Container cont = (Container)comp;
		Component retval = cont.getFocusTraversalPolicy().
		    getDefaultComponent(cont);
		if (retval != null) {
		    return retval;
		}
	    }
        }

        return null;
    }

    /**
     * Returns the Component that should receive the focus before aComponent.
     * aContainer must be a focus cycle root of aComponent or a <a
     * href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal policy
     * provider</a>. 
     *
     * @param aContainer a focus cycle root of aComponent or focus traversal policy provider
     * @param aComponent a (possibly indirect) child of aContainer, or
     *        aContainer itself
     * @return the Component that should receive the focus before aComponent,
     *         or null if no suitable Component can be found
     * @throws IllegalArgumentException if aContainer is not a focus cycle
     *         root of aComponent or focus traversal policy provider, or if either aContainer or
     *         aComponent is null
     */
    public Component getComponentBefore(Container aContainer,
                                        Component aComponent) {
        if (aContainer == null || aComponent == null) {
            throw new IllegalArgumentException("aContainer and aComponent cannot be null");
        }
        if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
            throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
        } else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
            throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
        }
        synchronized(aContainer.getTreeLock()) {
            found.value = false;
            Component retval = getComponentBefore(aContainer, aComponent,
                                                  found);
            if (retval != null) {
                if (log.isLoggable(Level.FINE)) log.fine("Before component is " + retval);
                return retval;
            } else if (found.value) {
                if (log.isLoggable(Level.FINE)) log.fine("Didn't find before component in " + aContainer + " - falling back to the first ");
                return getLastComponent(aContainer);
            } else {
                if (log.isLoggable(Level.FINE)) log.fine("Before component is null");
                return null;
            }
        }
    }

    private Component getComponentBefore(Container aContainer,
                                         Component aComponent,
                                         MutableBoolean found) {
        if (!(aContainer.isVisible() && aContainer.isDisplayable())) {
	    return null;
	}

        for (int i = aContainer.ncomponents - 1; i >= 0; i--) {
            Component comp = aContainer.component[i];
	    if (comp == aComponent) {
		found.value = true;
	    } else if ((comp instanceof Container) &&
                !((Container)comp).isFocusCycleRoot()) {
                Component retval = null;
                if (((Container)comp).isFocusTraversalPolicyProvider()) {
                    if (log.isLoggable(Level.FINE)) log.fine("Entering FTP " + comp);
                    Container cont = (Container) comp;
                    FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
                    if (log.isLoggable(Level.FINE)) log.fine("FTP contains " + aComponent + ": " + cont.isAncestorOf(aComponent));
                    if (found.value) {
                        retval = policy.getLastComponent(cont);
                        if (log.isLoggable(Level.FINE)) log.fine("Used FTP for getting last component: " + retval);
                    } else {
                        found.value = cont.isAncestorOf(aComponent);                    
                        if (found.value) {
                            if (aComponent == policy.getFirstComponent(cont)) {
                                retval = null;
                            } else {
                                retval = policy.getComponentBefore(cont, aComponent);
                                if (log.isLoggable(Level.FINE)) log.fine("FTP found previous for the component : " + retval);
                            }
                        }
                    }
                } else {
                    retval = getComponentBefore((Container)comp,
                                                      aComponent,
                                                      found);
                }
                if (retval != null) {
                    return retval;
                }
            } else if (found.value) {
                if (accept(comp)) {
                    return comp;
                }
            }
        }

        if (found.value) {
            if (accept(aContainer)) {
                return aContainer;
            }
        } else if (aContainer == aComponent) {
            found.value = true;
        }

        return null;
    }

    /**
     * Returns the first Component in the traversal cycle. This method is used
     * to determine the next Component to focus when traversal wraps in the
     * forward direction.
     *
     * @param aContainer the focus cycle root or focus traversal policy provider whose first
     *        Component is to be returned
     * @return the first Component in the traversal cycle of aContainer,
     *         or null if no suitable Component can be found
     * @throws IllegalArgumentException if aContainer is null
     */
    public Component getFirstComponent(Container aContainer) {
        if (aContainer == null) {
            throw new IllegalArgumentException("aContainer cannot be null");
        }

        synchronized(aContainer.getTreeLock()) {
            if (!(aContainer.isVisible() &&
                  aContainer.isDisplayable()))
	    {
                return null;
            }

            if (accept(aContainer)) {
                return aContainer;
            }

            for (int i = 0; i < aContainer.ncomponents; i++) {
                Component comp = aContainer.component[i];
		if (comp instanceof Container &&
		    !((Container)comp).isFocusCycleRoot())
		{
                    Component retval = null;
                    Container cont = (Container)comp;
                    if (cont.isFocusTraversalPolicyProvider()) {
                        FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
                        retval = policy.getDefaultComponent(cont);
                    } else {
                        retval = getFirstComponent((Container)comp);
                    }
		    if (retval != null) {
		        return retval;
		    }
		} else if (accept(comp)) {
		    return comp;
		}
            }
        }

        return null;
    }

    /**
     * Returns the last Component in the traversal cycle. This method is used
     * to determine the next Component to focus when traversal wraps in the
     * reverse direction.
     *
     * @param aContainer the focus cycle root or focus traversal policy provider whose last
     *        Component is to be returned
     * @return the last Component in the traversal cycle of aContainer,
     *         or null if no suitable Component can be found
     * @throws IllegalArgumentException if aContainer is null
     */
    public Component getLastComponent(Container aContainer) {
        if (aContainer == null) {
            throw new IllegalArgumentException("aContainer cannot be null");
        }
        if (log.isLoggable(Level.FINE)) log.fine("Looking for the last component in " + aContainer);

        synchronized(aContainer.getTreeLock()) {
            if (!(aContainer.isVisible() &&
                  aContainer.isDisplayable()))
	    {
                return null;
            }

            for (int i = aContainer.ncomponents - 1; i >= 0; i--) {
                Component comp = aContainer.component[i];
		if (comp instanceof Container &&
		    !((Container)comp).isFocusCycleRoot())
		{
                    Component retval = null;
                    Container cont = (Container)comp;
                    if (cont.isFocusTraversalPolicyProvider()) {
                        if (log.isLoggable(Level.FINE)) log.fine("\tEntering FTP " + cont);
                        FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
                        retval = policy.getLastComponent(cont);
                    } else {
                        if (log.isLoggable(Level.FINE)) log.fine("\tEntering sub-container");
                        retval = getLastComponent((Container)comp);
                    }
		    if (retval != null) {
                        if (log.isLoggable(Level.FINE)) log.fine("\tFound last component : " + retval);
		        return retval;
		    }
		} else if (accept(comp)) {
		    return comp;
		}
            }

            if (accept(aContainer)) {
                return aContainer;
            }
        }

        return null;
    }

    /**
     * Returns the default Component to focus. This Component will be the first
     * to receive focus when traversing down into a new focus traversal cycle
     * rooted at aContainer. The default implementation of this method
     * returns the same Component as <code>getFirstComponent</code>.
     *
     * @param aContainer the focus cycle root or focus traversal policy provider whose default
     *        Component is to be returned
     * @return the default Component in the traversal cycle of aContainer,
     *         or null if no suitable Component can be found
     * @see #getFirstComponent
     * @throws IllegalArgumentException if aContainer is null
     */
    public Component getDefaultComponent(Container aContainer) {
        return getFirstComponent(aContainer);
    }

    /**
     * Sets whether this ContainerOrderFocusTraversalPolicy transfers focus
     * down-cycle implicitly. If <code>true</code>, during normal forward focus
     * traversal, the Component traversed after a focus cycle root will be the
     * focus-cycle-root's default Component to focus. If <code>false</code>,
     * the next Component in the focus traversal cycle rooted at the specified
     * focus cycle root will be traversed instead. The default value for this
     * property is <code>true</code>.
     *
     * @param implicitDownCycleTraversal whether this
     *        ContainerOrderFocusTraversalPolicy transfers focus down-cycle
     *        implicitly
     * @see #getImplicitDownCycleTraversal
     * @see #getFirstComponent
     */
    public void setImplicitDownCycleTraversal(boolean
					      implicitDownCycleTraversal) {
	this.implicitDownCycleTraversal = implicitDownCycleTraversal;
    }

    /**
     * Returns whether this ContainerOrderFocusTraversalPolicy transfers focus
     * down-cycle implicitly. If <code>true</code>, during normal forward focus
     * traversal, the Component traversed after a focus cycle root will be the
     * focus-cycle-root's default Component to focus. If <code>false</code>,
     * the next Component in the focus traversal cycle rooted at the specified
     * focus cycle root will be traversed instead.
     *
     * @return whether this ContainerOrderFocusTraversalPolicy transfers focus
     *         down-cycle implicitly
     * @see #setImplicitDownCycleTraversal
     * @see #getFirstComponent
     */
    public boolean getImplicitDownCycleTraversal() {
	return implicitDownCycleTraversal;
    }

    /**
     * Determines whether a Component is an acceptable choice as the new
     * focus owner. By default, this method will accept a Component if and
     * only if it is visible, displayable, enabled, and focusable.
     *
     * @param aComponent the Component whose fitness as a focus owner is to
     *        be tested
     * @return <code>true</code> if aComponent is visible, displayable,
     *         enabled, and focusable; <code>false</code> otherwise
     */
    protected boolean accept(Component aComponent) {
	if (!(aComponent.isVisible() && aComponent.isDisplayable() &&
	      aComponent.isFocusable() && aComponent.isEnabled())) {
	    return false;
	}

	// Verify that the Component is recursively enabled. Disabling a
	// heavyweight Container disables its children, whereas disabling
	// a lightweight Container does not.
	if (!(aComponent instanceof Window)) {
	    for (Container enableTest = aComponent.getParent();
		 enableTest != null;
		 enableTest = enableTest.getParent())
	    {
		if (!(enableTest.isEnabled() || enableTest.isLightweight())) {
		    return false;
		}
		if (enableTest instanceof Window) {
		    break;
		}
	    }
	}

	return true;
    }

}


class MutableBoolean {
    boolean value = false;    
}

Generated By: JavaOnTracks Doclet 0.1.4     ©Thibaut Colar