1 /*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package javax.swing;
26
27 import java.awt.Component;
28 import java.util.ArrayList;
29 import java.util.Hashtable;
30 import java.awt.Color;
31 import java.awt.Graphics;
32 import java.awt.Rectangle;
33 import sun.awt.SunToolkit;
34
35 import javax.accessibility.*;
36
37 /**
38 * <code>JLayeredPane</code> adds depth to a JFC/Swing container,
39 * allowing components to overlap each other when needed.
40 * An <code>Integer</code> object specifies each component's depth in the
41 * container, where higher-numbered components sit "on top" of other
42 * components.
43 * For task-oriented documentation and examples of using layered panes see
44 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/layeredpane.html">How to Use a Layered Pane</a>,
45 * a section in <em>The Java Tutorial</em>.
46 *
47 * <TABLE STYLE="FLOAT:RIGHT" BORDER="0" SUMMARY="layout">
48 * <TR>
49 * <TD ALIGN="CENTER">
50 * <P STYLE="TEXT-ALIGN:CENTER"><IMG SRC="doc-files/JLayeredPane-1.gif"
51 * alt="The following text describes this image."
52 * WIDTH="269" HEIGHT="264" STYLE="FLOAT:BOTTOM; BORDER=0">
53 * </TD>
54 * </TR>
55 * </TABLE>
56 * For convenience, <code>JLayeredPane</code> divides the depth-range
57 * into several different layers. Putting a component into one of those
58 * layers makes it easy to ensure that components overlap properly,
59 * without having to worry about specifying numbers for specific depths:
60 * <DL>
61 * <DT>DEFAULT_LAYER</DT>
62 * <DD>The standard layer, where most components go. This the bottommost
63 * layer.
64 * <DT>PALETTE_LAYER</DT>
65 * <DD>The palette layer sits over the default layer. Useful for floating
66 * toolbars and palettes, so they can be positioned above other components.
67 * <DT>MODAL_LAYER</DT>
68 * <DD>The layer used for modal dialogs. They will appear on top of any
69 * toolbars, palettes, or standard components in the container.
70 * <DT>POPUP_LAYER</DT>
71 * <DD>The popup layer displays above dialogs. That way, the popup windows
72 * associated with combo boxes, tooltips, and other help text will appear
73 * above the component, palette, or dialog that generated them.
74 * <DT>DRAG_LAYER</DT>
75 * <DD>When dragging a component, reassigning it to the drag layer ensures
76 * that it is positioned over every other component in the container. When
77 * finished dragging, it can be reassigned to its normal layer.
78 * </DL>
79 * The <code>JLayeredPane</code> methods <code>moveToFront(Component)</code>,
80 * <code>moveToBack(Component)</code> and <code>setPosition</code> can be used
81 * to reposition a component within its layer. The <code>setLayer</code> method
82 * can also be used to change the component's current layer.
83 *
84 * <h2>Details</h2>
85 * <code>JLayeredPane</code> manages its list of children like
86 * <code>Container</code>, but allows for the definition of a several
87 * layers within itself. Children in the same layer are managed exactly
88 * like the normal <code>Container</code> object,
89 * with the added feature that when children components overlap, children
90 * in higher layers display above the children in lower layers.
91 * <p>
92 * Each layer is a distinct integer number. The layer attribute can be set
93 * on a <code>Component</code> by passing an <code>Integer</code>
94 * object during the add call.<br> For example:
95 * <PRE>
96 * layeredPane.add(child, JLayeredPane.DEFAULT_LAYER);
97 * or
98 * layeredPane.add(child, new Integer(10));
99 * </PRE>
100 * The layer attribute can also be set on a Component by calling<PRE>
101 * layeredPaneParent.setLayer(child, 10)</PRE>
102 * on the <code>JLayeredPane</code> that is the parent of component. The layer
103 * should be set <i>before</i> adding the child to the parent.
104 * <p>
105 * Higher number layers display above lower number layers. So, using
106 * numbers for the layers and letters for individual components, a
107 * representative list order would look like this:<PRE>
108 * 5a, 5b, 5c, 2a, 2b, 2c, 1a </PRE>
109 * where the leftmost components are closest to the top of the display.
110 * <p>
111 * A component can be moved to the top or bottom position within its
112 * layer by calling <code>moveToFront</code> or <code>moveToBack</code>.
113 * <p>
114 * The position of a component within a layer can also be specified directly.
115 * Valid positions range from 0 up to one less than the number of
116 * components in that layer. A value of -1 indicates the bottommost
117 * position. A value of 0 indicates the topmost position. Unlike layer
118 * numbers, higher position values are <i>lower</i> in the display.
119 * <blockquote>
120 * <b>Note:</b> This sequence (defined by java.awt.Container) is the reverse
121 * of the layer numbering sequence. Usually though, you will use <code>moveToFront</code>,
122 * <code>moveToBack</code>, and <code>setLayer</code>.
123 * </blockquote>
124 * Here are some examples using the method add(Component, layer, position):
125 * Calling add(5x, 5, -1) results in:<PRE>
126 * 5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
127 *
128 * Calling add(5z, 5, 2) results in:<PRE>
129 * 5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
130 *
131 * Calling add(3a, 3, 7) results in:<PRE>
132 * 5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a </PRE>
133 *
134 * Using normal paint/event mechanics results in 1a appearing at the bottom
135 * and 5a being above all other components.
136 * <p>
137 * <b>Note:</b> that these layers are simply a logical construct and LayoutManagers
138 * will affect all child components of this container without regard for
139 * layer settings.
140 * <p>
141 * <strong>Warning:</strong> Swing is not thread safe. For more
142 * information see <a
143 * href="package-summary.html#threading">Swing's Threading
144 * Policy</a>.
145 * <p>
146 * <strong>Warning:</strong>
147 * Serialized objects of this class will not be compatible with
148 * future Swing releases. The current serialization support is
149 * appropriate for short term storage or RMI between applications running
150 * the same version of Swing. As of 1.4, support for long term storage
151 * of all JavaBeans™
152 * has been added to the <code>java.beans</code> package.
153 * Please see {@link java.beans.XMLEncoder}.
154 *
155 * @author David Kloba
156 * @since 1.2
157 */
158 @SuppressWarnings("serial")
159 public class JLayeredPane extends JComponent implements Accessible {
160 /// Watch the values in getObjectForLayer()
161 /** Convenience object defining the Default layer. Equivalent to new Integer(0).*/
162 public final static Integer DEFAULT_LAYER = 0;
163 /** Convenience object defining the Palette layer. Equivalent to new Integer(100).*/
164 public final static Integer PALETTE_LAYER = 100;
165 /** Convenience object defining the Modal layer. Equivalent to new Integer(200).*/
166 public final static Integer MODAL_LAYER = 200;
167 /** Convenience object defining the Popup layer. Equivalent to new Integer(300).*/
168 public final static Integer POPUP_LAYER = 300;
169 /** Convenience object defining the Drag layer. Equivalent to new Integer(400).*/
170 public final static Integer DRAG_LAYER = 400;
171 /** Convenience object defining the Frame Content layer.
172 * This layer is normally only use to position the contentPane and menuBar
173 * components of JFrame.
174 * Equivalent to new Integer(-30000).
175 * @see JFrame
176 */
177 public final static Integer FRAME_CONTENT_LAYER = new Integer(-30000);
178
179 /** Bound property */
180 public final static String LAYER_PROPERTY = "layeredContainerLayer";
181 // Hashtable to store layer values for non-JComponent components
182 private Hashtable<Component,Integer> componentToLayer;
183 private boolean optimizedDrawingPossible = true;
184
185
186 //////////////////////////////////////////////////////////////////////////////
187 //// Container Override methods
188 //////////////////////////////////////////////////////////////////////////////
189 /** Create a new JLayeredPane */
190 public JLayeredPane() {
191 setLayout(null);
192 }
193
194 private void validateOptimizedDrawing() {
195 boolean layeredComponentFound = false;
196 synchronized(getTreeLock()) {
197 Integer layer;
198
199 for (Component c : getComponents()) {
200 layer = null;
201
202 if(SunToolkit.isInstanceOf(c, "javax.swing.JInternalFrame") ||
203 (c instanceof JComponent &&
204 (layer = (Integer)((JComponent)c).
205 getClientProperty(LAYER_PROPERTY)) != null))
206 {
207 if(layer != null && layer.equals(FRAME_CONTENT_LAYER))
208 continue;
209 layeredComponentFound = true;
210 break;
211 }
212 }
213 }
214
215 if(layeredComponentFound)
216 optimizedDrawingPossible = false;
217 else
218 optimizedDrawingPossible = true;
219 }
220
221 protected void addImpl(Component comp, Object constraints, int index) {
222 int layer;
223 int pos;
224
225 if(constraints instanceof Integer) {
226 layer = ((Integer)constraints).intValue();
227 setLayer(comp, layer);
228 } else
229 layer = getLayer(comp);
230
231 pos = insertIndexForLayer(layer, index);
232 super.addImpl(comp, constraints, pos);
233 comp.validate();
234 comp.repaint();
235 validateOptimizedDrawing();
236 }
237
238 /**
239 * Remove the indexed component from this pane.
240 * This is the absolute index, ignoring layers.
241 *
242 * @param index an int specifying the component to remove
243 * @see #getIndexOf
244 */
245 public void remove(int index) {
246 Component c = getComponent(index);
247 super.remove(index);
248 if (c != null && !(c instanceof JComponent)) {
249 getComponentToLayer().remove(c);
250 }
251 validateOptimizedDrawing();
252 }
253
254 /**
255 * Removes all the components from this container.
256 *
257 * @since 1.5
258 */
259 public void removeAll() {
260 Component[] children = getComponents();
261 Hashtable<Component, Integer> cToL = getComponentToLayer();
262 for (int counter = children.length - 1; counter >= 0; counter--) {
263 Component c = children[counter];
264 if (c != null && !(c instanceof JComponent)) {
265 cToL.remove(c);
266 }
267 }
268 super.removeAll();
269 }
270
271 /**
272 * Returns false if components in the pane can overlap, which makes
273 * optimized drawing impossible. Otherwise, returns true.
274 *
275 * @return false if components can overlap, else true
276 * @see JComponent#isOptimizedDrawingEnabled
277 */
278 public boolean isOptimizedDrawingEnabled() {
279 return optimizedDrawingPossible;
280 }
281
282
283 //////////////////////////////////////////////////////////////////////////////
284 //// New methods for managing layers
285 //////////////////////////////////////////////////////////////////////////////
286 /** Sets the layer property on a JComponent. This method does not cause
287 * any side effects like setLayer() (painting, add/remove, etc).
288 * Normally you should use the instance method setLayer(), in order to
289 * get the desired side-effects (like repainting).
290 *
291 * @param c the JComponent to move
292 * @param layer an int specifying the layer to move it to
293 * @see #setLayer
294 */
295 public static void putLayer(JComponent c, int layer) {
296 /// MAKE SURE THIS AND setLayer(Component c, int layer, int position) are SYNCED
297 c.putClientProperty(LAYER_PROPERTY, layer);
298 }
299
300 /** Gets the layer property for a JComponent, it
301 * does not cause any side effects like setLayer(). (painting, add/remove, etc)
302 * Normally you should use the instance method getLayer().
303 *
304 * @param c the JComponent to check
305 * @return an int specifying the component's layer
306 */
307 public static int getLayer(JComponent c) {
308 Integer i;
309 if((i = (Integer)c.getClientProperty(LAYER_PROPERTY)) != null)
310 return i.intValue();
311 return DEFAULT_LAYER.intValue();
312 }
313
314 /** Convenience method that returns the first JLayeredPane which
315 * contains the specified component. Note that all JFrames have a
316 * JLayeredPane at their root, so any component in a JFrame will
317 * have a JLayeredPane parent.
318 *
319 * @param c the Component to check
320 * @return the JLayeredPane that contains the component, or
321 * null if no JLayeredPane is found in the component
322 * hierarchy
323 * @see JFrame
324 * @see JRootPane
325 */
326 public static JLayeredPane getLayeredPaneAbove(Component c) {
327 if(c == null) return null;
328
329 Component parent = c.getParent();
330 while(parent != null && !(parent instanceof JLayeredPane))
331 parent = parent.getParent();
332 return (JLayeredPane)parent;
333 }
334
335 /** Sets the layer attribute on the specified component,
336 * making it the bottommost component in that layer.
337 * Should be called before adding to parent.
338 *
339 * @param c the Component to set the layer for
340 * @param layer an int specifying the layer to set, where
341 * lower numbers are closer to the bottom
342 */
343 public void setLayer(Component c, int layer) {
344 setLayer(c, layer, -1);
345 }
346
347 /** Sets the layer attribute for the specified component and
348 * also sets its position within that layer.
349 *
350 * @param c the Component to set the layer for
351 * @param layer an int specifying the layer to set, where
352 * lower numbers are closer to the bottom
353 * @param position an int specifying the position within the
354 * layer, where 0 is the topmost position and -1
355 * is the bottommost position
356 */
357 public void setLayer(Component c, int layer, int position) {
358 Integer layerObj;
359 layerObj = getObjectForLayer(layer);
360
361 if(layer == getLayer(c) && position == getPosition(c)) {
362 repaint(c.getBounds());
363 return;
364 }
365
366 /// MAKE SURE THIS AND putLayer(JComponent c, int layer) are SYNCED
367 if(c instanceof JComponent)
368 ((JComponent)c).putClientProperty(LAYER_PROPERTY, layerObj);
369 else
370 getComponentToLayer().put(c, layerObj);
371
372 if(c.getParent() == null || c.getParent() != this) {
373 repaint(c.getBounds());
374 return;
375 }
376
377 int index = insertIndexForLayer(c, layer, position);
378
379 setComponentZOrder(c, index);
380 repaint(c.getBounds());
381 }
382
383 /**
384 * Returns the layer attribute for the specified Component.
385 *
386 * @param c the Component to check
387 * @return an int specifying the component's current layer
388 */
389 public int getLayer(Component c) {
390 Integer i;
391 if(c instanceof JComponent)
392 i = (Integer)((JComponent)c).getClientProperty(LAYER_PROPERTY);
393 else
394 i = getComponentToLayer().get(c);
395
396 if(i == null)
397 return DEFAULT_LAYER.intValue();
398 return i.intValue();
399 }
400
401 /**
402 * Returns the index of the specified Component.
403 * This is the absolute index, ignoring layers.
404 * Index numbers, like position numbers, have the topmost component
405 * at index zero. Larger numbers are closer to the bottom.
406 *
407 * @param c the Component to check
408 * @return an int specifying the component's index
409 */
410 public int getIndexOf(Component c) {
411 int i, count;
412
413 count = getComponentCount();
414 for(i = 0; i < count; i++) {
415 if(c == getComponent(i))
416 return i;
417 }
418 return -1;
419 }
420 /**
421 * Moves the component to the top of the components in its current layer
422 * (position 0).
423 *
424 * @param c the Component to move
425 * @see #setPosition(Component, int)
426 */
427 public void moveToFront(Component c) {
428 setPosition(c, 0);
429 }
430
431 /**
432 * Moves the component to the bottom of the components in its current layer
433 * (position -1).
434 *
435 * @param c the Component to move
436 * @see #setPosition(Component, int)
437 */
438 public void moveToBack(Component c) {
439 setPosition(c, -1);
440 }
441
442 /**
443 * Moves the component to <code>position</code> within its current layer,
444 * where 0 is the topmost position within the layer and -1 is the bottommost
445 * position.
446 * <p>
447 * <b>Note:</b> Position numbering is defined by java.awt.Container, and
448 * is the opposite of layer numbering. Lower position numbers are closer
449 * to the top (0 is topmost), and higher position numbers are closer to
450 * the bottom.
451 *
452 * @param c the Component to move
453 * @param position an int in the range -1..N-1, where N is the number of
454 * components in the component's current layer
455 */
456 public void setPosition(Component c, int position) {
457 setLayer(c, getLayer(c), position);
458 }
459
460 /**
461 * Get the relative position of the component within its layer.
462 *
463 * @param c the Component to check
464 * @return an int giving the component's position, where 0 is the
465 * topmost position and the highest index value = the count
466 * count of components at that layer, minus 1
467 *
468 * @see #getComponentCountInLayer
469 */
470 public int getPosition(Component c) {
471 int i, startLayer, curLayer, startLocation, pos = 0;
472
473 getComponentCount();
474 startLocation = getIndexOf(c);
475
476 if(startLocation == -1)
477 return -1;
478
479 startLayer = getLayer(c);
480 for(i = startLocation - 1; i >= 0; i--) {
481 curLayer = getLayer(getComponent(i));
482 if(curLayer == startLayer)
483 pos++;
484 else
485 return pos;
486 }
487 return pos;
488 }
489
490 /** Returns the highest layer value from all current children.
491 * Returns 0 if there are no children.
492 *
493 * @return an int indicating the layer of the topmost component in the
494 * pane, or zero if there are no children
495 */
496 public int highestLayer() {
497 if(getComponentCount() > 0)
498 return getLayer(getComponent(0));
499 return 0;
500 }
501
502 /** Returns the lowest layer value from all current children.
503 * Returns 0 if there are no children.
504 *
505 * @return an int indicating the layer of the bottommost component in the
506 * pane, or zero if there are no children
507 */
508 public int lowestLayer() {
509 int count = getComponentCount();
510 if(count > 0)
511 return getLayer(getComponent(count-1));
512 return 0;
513 }
514
515 /**
516 * Returns the number of children currently in the specified layer.
517 *
518 * @param layer an int specifying the layer to check
519 * @return an int specifying the number of components in that layer
520 */
521 public int getComponentCountInLayer(int layer) {
522 int i, count, curLayer;
523 int layerCount = 0;
524
525 count = getComponentCount();
526 for(i = 0; i < count; i++) {
527 curLayer = getLayer(getComponent(i));
528 if(curLayer == layer) {
529 layerCount++;
530 /// Short circut the counting when we have them all
531 } else if(layerCount > 0 || curLayer < layer) {
532 break;
533 }
534 }
535
536 return layerCount;
537 }
538
539 /**
540 * Returns an array of the components in the specified layer.
541 *
542 * @param layer an int specifying the layer to check
543 * @return an array of Components contained in that layer
544 */
545 public Component[] getComponentsInLayer(int layer) {
546 int i, count, curLayer;
547 int layerCount = 0;
548 Component[] results;
549
550 results = new Component[getComponentCountInLayer(layer)];
551 count = getComponentCount();
552 for(i = 0; i < count; i++) {
553 curLayer = getLayer(getComponent(i));
554 if(curLayer == layer) {
555 results[layerCount++] = getComponent(i);
556 /// Short circut the counting when we have them all
557 } else if(layerCount > 0 || curLayer < layer) {
558 break;
559 }
560 }
561
562 return results;
563 }
564
565 /**
566 * Paints this JLayeredPane within the specified graphics context.
567 *
568 * @param g the Graphics context within which to paint
569 */
570 public void paint(Graphics g) {
571 if(isOpaque()) {
572 Rectangle r = g.getClipBounds();
573 Color c = getBackground();
574 if(c == null)
575 c = Color.lightGray;
576 g.setColor(c);
577 if (r != null) {
578 g.fillRect(r.x, r.y, r.width, r.height);
579 }
580 else {
581 g.fillRect(0, 0, getWidth(), getHeight());
582 }
583 }
584 super.paint(g);
585 }
586
587 //////////////////////////////////////////////////////////////////////////////
588 //// Implementation Details
589 //////////////////////////////////////////////////////////////////////////////
590
591 /**
592 * Returns the hashtable that maps components to layers.
593 *
594 * @return the Hashtable used to map components to their layers
595 */
596 protected Hashtable<Component,Integer> getComponentToLayer() {
597 if(componentToLayer == null)
598 componentToLayer = new Hashtable<Component,Integer>(4);
599 return componentToLayer;
600 }
601
602 /**
603 * Returns the Integer object associated with a specified layer.
604 *
605 * @param layer an int specifying the layer
606 * @return an Integer object for that layer
607 */
608 protected Integer getObjectForLayer(int layer) {
609 switch(layer) {
610 case 0:
611 return DEFAULT_LAYER;
612 case 100:
613 return PALETTE_LAYER;
614 case 200:
615 return MODAL_LAYER;
616 case 300:
617 return POPUP_LAYER;
618 case 400:
619 return DRAG_LAYER;
620 default:
621 return layer;
622 }
623 }
624
625 /**
626 * Primitive method that determines the proper location to
627 * insert a new child based on layer and position requests.
628 *
629 * @param layer an int specifying the layer
630 * @param position an int specifying the position within the layer
631 * @return an int giving the (absolute) insertion-index
632 *
633 * @see #getIndexOf
634 */
635 protected int insertIndexForLayer(int layer, int position) {
636 return insertIndexForLayer(null, layer, position);
637 }
638
639 /**
640 * This method is an extended version of insertIndexForLayer()
641 * to support setLayer which uses Container.setZOrder which does
642 * not remove the component from the containment hierarchy though
643 * we need to ignore it when calculating the insertion index.
644 *
645 * @param comp component to ignore when determining index
646 * @param layer an int specifying the layer
647 * @param position an int specifying the position within the layer
648 * @return an int giving the (absolute) insertion-index
649 *
650 * @see #getIndexOf
651 */
652 private int insertIndexForLayer(Component comp, int layer, int position) {
653 int i, count, curLayer;
654 int layerStart = -1;
655 int layerEnd = -1;
656 int componentCount = getComponentCount();
657
658 ArrayList<Component> compList =
659 new ArrayList<Component>(componentCount);
660 for (int index = 0; index < componentCount; index++) {
661 if (getComponent(index) != comp) {
662 compList.add(getComponent(index));
663 }
664 }
665
666 count = compList.size();
667 for (i = 0; i < count; i++) {
668 curLayer = getLayer(compList.get(i));
669 if (layerStart == -1 && curLayer == layer) {
670 layerStart = i;
671 }
672 if (curLayer < layer) {
673 if (i == 0) {
674 // layer is greater than any current layer
675 // [ ASSERT(layer > highestLayer()) ]
676 layerStart = 0;
677 layerEnd = 0;
678 } else {
679 layerEnd = i;
680 }
681 break;
682 }
683 }
684
685 // layer requested is lower than any current layer
686 // [ ASSERT(layer < lowestLayer()) ]
687 // put it on the bottom of the stack
688 if (layerStart == -1 && layerEnd == -1)
689 return count;
690
691 // In the case of a single layer entry handle the degenerative cases
692 if (layerStart != -1 && layerEnd == -1)
693 layerEnd = count;
694
695 if (layerEnd != -1 && layerStart == -1)
696 layerStart = layerEnd;
697
698 // If we are adding to the bottom, return the last element
699 if (position == -1)
700 return layerEnd;
701
702 // Otherwise make sure the requested position falls in the
703 // proper range
704 if (position > -1 && layerStart + position <= layerEnd)
705 return layerStart + position;
706
707 // Otherwise return the end of the layer
708 return layerEnd;
709 }
710
711 /**
712 * Returns a string representation of this JLayeredPane. This method
713 * is intended to be used only for debugging purposes, and the
714 * content and format of the returned string may vary between
715 * implementations. The returned string may be empty but may not
716 * be <code>null</code>.
717 *
718 * @return a string representation of this JLayeredPane.
719 */
720 protected String paramString() {
721 String optimizedDrawingPossibleString = (optimizedDrawingPossible ?
722 "true" : "false");
723
724 return super.paramString() +
725 ",optimizedDrawingPossible=" + optimizedDrawingPossibleString;
726 }
727
728 /////////////////
729 // Accessibility support
730 ////////////////
731
732 /**
733 * Gets the AccessibleContext associated with this JLayeredPane.
734 * For layered panes, the AccessibleContext takes the form of an
735 * AccessibleJLayeredPane.
736 * A new AccessibleJLayeredPane instance is created if necessary.
737 *
738 * @return an AccessibleJLayeredPane that serves as the
739 * AccessibleContext of this JLayeredPane
740 */
741 public AccessibleContext getAccessibleContext() {
742 if (accessibleContext == null) {
743 accessibleContext = new AccessibleJLayeredPane();
744 }
745 return accessibleContext;
746 }
747
748 /**
749 * This class implements accessibility support for the
750 * <code>JLayeredPane</code> class. It provides an implementation of the
751 * Java Accessibility API appropriate to layered pane user-interface
752 * elements.
753 * <p>
754 * <strong>Warning:</strong>
755 * Serialized objects of this class will not be compatible with
756 * future Swing releases. The current serialization support is
757 * appropriate for short term storage or RMI between applications running
758 * the same version of Swing. As of 1.4, support for long term storage
759 * of all JavaBeans™
760 * has been added to the <code>java.beans</code> package.
761 * Please see {@link java.beans.XMLEncoder}.
762 */
763 @SuppressWarnings("serial")
764 protected class AccessibleJLayeredPane extends AccessibleJComponent {
765
766 /**
767 * Get the role of this object.
768 *
769 * @return an instance of AccessibleRole describing the role of the
770 * object
771 * @see AccessibleRole
772 */
773 public AccessibleRole getAccessibleRole() {
774 return AccessibleRole.LAYERED_PANE;
775 }
776 }
777 }