1 /* 2 * Copyright (c) 1997, 2017, 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 java.beans.JavaBean; 34 import java.beans.BeanProperty; 35 36 import sun.awt.SunToolkit; 37 38 import javax.accessibility.*; 39 40 /** 41 * <code>JLayeredPane</code> adds depth to a JFC/Swing container, 42 * allowing components to overlap each other when needed. 43 * An <code>Integer</code> object specifies each component's depth in the 44 * container, where higher-numbered components sit "on top" of other 45 * components. 46 * For task-oriented documentation and examples of using layered panes see 47 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/layeredpane.html">How to Use a Layered Pane</a>, 48 * a section in <em>The Java Tutorial</em>. 49 * 50 * <TABLE STYLE="FLOAT:RIGHT" BORDER="0" SUMMARY="layout"> 51 * <TR> 52 * <TD style="text-align:center"> 53 * <P STYLE="TEXT-ALIGN:CENTER"><IMG SRC="doc-files/JLayeredPane-1.gif" 54 * alt="The following text describes this image." 55 * WIDTH="269" HEIGHT="264" STYLE="FLOAT:BOTTOM; BORDER=0"> 56 * </TD> 57 * </TR> 58 * </TABLE> 59 * For convenience, <code>JLayeredPane</code> divides the depth-range 60 * into several different layers. Putting a component into one of those 61 * layers makes it easy to ensure that components overlap properly, 62 * without having to worry about specifying numbers for specific depths: 63 * <DL> 64 * <DT>DEFAULT_LAYER</DT> 65 * <DD>The standard layer, where most components go. This the bottommost 66 * layer. 67 * <DT>PALETTE_LAYER</DT> 68 * <DD>The palette layer sits over the default layer. Useful for floating 69 * toolbars and palettes, so they can be positioned above other components. 70 * <DT>MODAL_LAYER</DT> 71 * <DD>The layer used for modal dialogs. They will appear on top of any 72 * toolbars, palettes, or standard components in the container. 73 * <DT>POPUP_LAYER</DT> 74 * <DD>The popup layer displays above dialogs. That way, the popup windows 75 * associated with combo boxes, tooltips, and other help text will appear 76 * above the component, palette, or dialog that generated them. 77 * <DT>DRAG_LAYER</DT> 78 * <DD>When dragging a component, reassigning it to the drag layer ensures 79 * that it is positioned over every other component in the container. When 80 * finished dragging, it can be reassigned to its normal layer. 81 * </DL> 82 * The <code>JLayeredPane</code> methods <code>moveToFront(Component)</code>, 83 * <code>moveToBack(Component)</code> and <code>setPosition</code> can be used 84 * to reposition a component within its layer. The <code>setLayer</code> method 85 * can also be used to change the component's current layer. 86 * 87 * <h2>Details</h2> 88 * <code>JLayeredPane</code> manages its list of children like 89 * <code>Container</code>, but allows for the definition of a several 90 * layers within itself. Children in the same layer are managed exactly 91 * like the normal <code>Container</code> object, 92 * with the added feature that when children components overlap, children 93 * in higher layers display above the children in lower layers. 94 * <p> 95 * Each layer is a distinct integer number. The layer attribute can be set 96 * on a <code>Component</code> by passing an <code>Integer</code> 97 * object during the add call.<br> For example: 98 * <PRE> 99 * layeredPane.add(child, JLayeredPane.DEFAULT_LAYER); 100 * or 101 * layeredPane.add(child, Integer.valueOf.valueOf(10)); 102 * </PRE> 103 * The layer attribute can also be set on a Component by calling<PRE> 104 * layeredPaneParent.setLayer(child, 10)</PRE> 105 * on the <code>JLayeredPane</code> that is the parent of component. The layer 106 * should be set <i>before</i> adding the child to the parent. 107 * <p> 108 * Higher number layers display above lower number layers. So, using 109 * numbers for the layers and letters for individual components, a 110 * representative list order would look like this:<PRE> 111 * 5a, 5b, 5c, 2a, 2b, 2c, 1a </PRE> 112 * where the leftmost components are closest to the top of the display. 113 * <p> 114 * A component can be moved to the top or bottom position within its 115 * layer by calling <code>moveToFront</code> or <code>moveToBack</code>. 116 * <p> 117 * The position of a component within a layer can also be specified directly. 118 * Valid positions range from 0 up to one less than the number of 119 * components in that layer. A value of -1 indicates the bottommost 120 * position. A value of 0 indicates the topmost position. Unlike layer 121 * numbers, higher position values are <i>lower</i> in the display. 122 * <blockquote> 123 * <b>Note:</b> This sequence (defined by java.awt.Container) is the reverse 124 * of the layer numbering sequence. Usually though, you will use <code>moveToFront</code>, 125 * <code>moveToBack</code>, and <code>setLayer</code>. 126 * </blockquote> 127 * Here are some examples using the method add(Component, layer, position): 128 * Calling add(5x, 5, -1) results in:<PRE> 129 * 5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a </PRE> 130 * 131 * Calling add(5z, 5, 2) results in:<PRE> 132 * 5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a </PRE> 133 * 134 * Calling add(3a, 3, 7) results in:<PRE> 135 * 5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a </PRE> 136 * 137 * Using normal paint/event mechanics results in 1a appearing at the bottom 138 * and 5a being above all other components. 139 * <p> 140 * <b>Note:</b> that these layers are simply a logical construct and LayoutManagers 141 * will affect all child components of this container without regard for 142 * layer settings. 143 * <p> 144 * <strong>Warning:</strong> Swing is not thread safe. For more 145 * information see <a 146 * href="package-summary.html#threading">Swing's Threading 147 * Policy</a>. 148 * <p> 149 * <strong>Warning:</strong> 150 * Serialized objects of this class will not be compatible with 151 * future Swing releases. The current serialization support is 152 * appropriate for short term storage or RMI between applications running 153 * the same version of Swing. As of 1.4, support for long term storage 154 * of all JavaBeans™ 155 * has been added to the <code>java.beans</code> package. 156 * Please see {@link java.beans.XMLEncoder}. 157 * 158 * @author David Kloba 159 * @since 1.2 160 */ 161 @JavaBean(defaultProperty = "accessibleContext") 162 @SuppressWarnings("serial") 163 public class JLayeredPane extends JComponent implements Accessible { 164 /// Watch the values in getObjectForLayer() 165 /** Convenience object defining the Default layer. Equivalent to Integer.valueOf(0).*/ 166 public static final Integer DEFAULT_LAYER = 0; 167 /** Convenience object defining the Palette layer. Equivalent to Integer.valueOf(100).*/ 168 public static final Integer PALETTE_LAYER = 100; 169 /** Convenience object defining the Modal layer. Equivalent to Integer.valueOf(200).*/ 170 public static final Integer MODAL_LAYER = 200; 171 /** Convenience object defining the Popup layer. Equivalent to Integer.valueOf(300).*/ 172 public static final Integer POPUP_LAYER = 300; 173 /** Convenience object defining the Drag layer. Equivalent to Integer.valueOf(400).*/ 174 public static final Integer DRAG_LAYER = 400; 175 /** Convenience object defining the Frame Content layer. 176 * This layer is normally only use to position the contentPane and menuBar 177 * components of JFrame. 178 * Equivalent to Integer.valueOf(-30000). 179 * @see JFrame 180 */ 181 public static final Integer FRAME_CONTENT_LAYER = -30000; 182 183 /** Bound property */ 184 public static final String LAYER_PROPERTY = "layeredContainerLayer"; 185 // Hashtable to store layer values for non-JComponent components 186 private Hashtable<Component,Integer> componentToLayer; 187 private boolean optimizedDrawingPossible = true; 188 189 190 ////////////////////////////////////////////////////////////////////////////// 191 //// Container Override methods 192 ////////////////////////////////////////////////////////////////////////////// 193 /** Create a new JLayeredPane */ 194 public JLayeredPane() { 195 setLayout(null); 196 } 197 198 private void validateOptimizedDrawing() { 199 boolean layeredComponentFound = false; 200 synchronized(getTreeLock()) { 201 Integer layer; 202 203 for (Component c : getComponents()) { 204 layer = null; 205 206 if(SunToolkit.isInstanceOf(c, "javax.swing.JInternalFrame") || 207 (c instanceof JComponent && 208 (layer = (Integer)((JComponent)c). 209 getClientProperty(LAYER_PROPERTY)) != null)) 210 { 211 if(layer != null && layer.equals(FRAME_CONTENT_LAYER)) 212 continue; 213 layeredComponentFound = true; 214 break; 215 } 216 } 217 } 218 219 if(layeredComponentFound) 220 optimizedDrawingPossible = false; 221 else 222 optimizedDrawingPossible = true; 223 } 224 225 protected void addImpl(Component comp, Object constraints, int index) { 226 int layer; 227 int pos; 228 229 if(constraints instanceof Integer) { 230 layer = ((Integer)constraints).intValue(); 231 setLayer(comp, layer); 232 } else 233 layer = getLayer(comp); 234 235 pos = insertIndexForLayer(layer, index); 236 super.addImpl(comp, constraints, pos); 237 comp.validate(); 238 comp.repaint(); 239 validateOptimizedDrawing(); 240 } 241 242 /** 243 * Remove the indexed component from this pane. 244 * This is the absolute index, ignoring layers. 245 * 246 * @param index an int specifying the component to remove 247 * @see #getIndexOf 248 */ 249 public void remove(int index) { 250 Component c = getComponent(index); 251 super.remove(index); 252 if (c != null && !(c instanceof JComponent)) { 253 getComponentToLayer().remove(c); 254 } 255 validateOptimizedDrawing(); 256 } 257 258 /** 259 * Removes all the components from this container. 260 * 261 * @since 1.5 262 */ 263 public void removeAll() { 264 Component[] children = getComponents(); 265 Hashtable<Component, Integer> cToL = getComponentToLayer(); 266 for (int counter = children.length - 1; counter >= 0; counter--) { 267 Component c = children[counter]; 268 if (c != null && !(c instanceof JComponent)) { 269 cToL.remove(c); 270 } 271 } 272 super.removeAll(); 273 } 274 275 /** 276 * Returns false if components in the pane can overlap, which makes 277 * optimized drawing impossible. Otherwise, returns true. 278 * 279 * @return false if components can overlap, else true 280 * @see JComponent#isOptimizedDrawingEnabled 281 */ 282 @BeanProperty(bound = false) 283 public boolean isOptimizedDrawingEnabled() { 284 return optimizedDrawingPossible; 285 } 286 287 288 ////////////////////////////////////////////////////////////////////////////// 289 //// New methods for managing layers 290 ////////////////////////////////////////////////////////////////////////////// 291 /** Sets the layer property on a JComponent. This method does not cause 292 * any side effects like setLayer() (painting, add/remove, etc). 293 * Normally you should use the instance method setLayer(), in order to 294 * get the desired side-effects (like repainting). 295 * 296 * @param c the JComponent to move 297 * @param layer an int specifying the layer to move it to 298 * @see #setLayer 299 */ 300 public static void putLayer(JComponent c, int layer) { 301 /// MAKE SURE THIS AND setLayer(Component c, int layer, int position) are SYNCED 302 c.putClientProperty(LAYER_PROPERTY, layer); 303 } 304 305 /** Gets the layer property for a JComponent, it 306 * does not cause any side effects like setLayer(). (painting, add/remove, etc) 307 * Normally you should use the instance method getLayer(). 308 * 309 * @param c the JComponent to check 310 * @return an int specifying the component's layer 311 */ 312 public static int getLayer(JComponent c) { 313 Integer i; 314 if((i = (Integer)c.getClientProperty(LAYER_PROPERTY)) != null) 315 return i.intValue(); 316 return DEFAULT_LAYER.intValue(); 317 } 318 319 /** Convenience method that returns the first JLayeredPane which 320 * contains the specified component. Note that all JFrames have a 321 * JLayeredPane at their root, so any component in a JFrame will 322 * have a JLayeredPane parent. 323 * 324 * @param c the Component to check 325 * @return the JLayeredPane that contains the component, or 326 * null if no JLayeredPane is found in the component 327 * hierarchy 328 * @see JFrame 329 * @see JRootPane 330 */ 331 public static JLayeredPane getLayeredPaneAbove(Component c) { 332 if(c == null) return null; 333 334 Component parent = c.getParent(); 335 while(parent != null && !(parent instanceof JLayeredPane)) 336 parent = parent.getParent(); 337 return (JLayeredPane)parent; 338 } 339 340 /** Sets the layer attribute on the specified component, 341 * making it the bottommost component in that layer. 342 * Should be called before adding to parent. 343 * 344 * @param c the Component to set the layer for 345 * @param layer an int specifying the layer to set, where 346 * lower numbers are closer to the bottom 347 */ 348 public void setLayer(Component c, int layer) { 349 setLayer(c, layer, -1); 350 } 351 352 /** Sets the layer attribute for the specified component and 353 * also sets its position within that layer. 354 * 355 * @param c the Component to set the layer for 356 * @param layer an int specifying the layer to set, where 357 * lower numbers are closer to the bottom 358 * @param position an int specifying the position within the 359 * layer, where 0 is the topmost position and -1 360 * is the bottommost position 361 */ 362 public void setLayer(Component c, int layer, int position) { 363 Integer layerObj; 364 layerObj = getObjectForLayer(layer); 365 366 if(layer == getLayer(c) && position == getPosition(c)) { 367 repaint(c.getBounds()); 368 return; 369 } 370 371 /// MAKE SURE THIS AND putLayer(JComponent c, int layer) are SYNCED 372 if(c instanceof JComponent) 373 ((JComponent)c).putClientProperty(LAYER_PROPERTY, layerObj); 374 else 375 getComponentToLayer().put(c, layerObj); 376 377 if(c.getParent() == null || c.getParent() != this) { 378 repaint(c.getBounds()); 379 return; 380 } 381 382 int index = insertIndexForLayer(c, layer, position); 383 384 setComponentZOrder(c, index); 385 repaint(c.getBounds()); 386 } 387 388 /** 389 * Returns the layer attribute for the specified Component. 390 * 391 * @param c the Component to check 392 * @return an int specifying the component's current layer 393 */ 394 public int getLayer(Component c) { 395 Integer i; 396 if(c instanceof JComponent) 397 i = (Integer)((JComponent)c).getClientProperty(LAYER_PROPERTY); 398 else 399 i = getComponentToLayer().get(c); 400 401 if(i == null) 402 return DEFAULT_LAYER.intValue(); 403 return i.intValue(); 404 } 405 406 /** 407 * Returns the index of the specified Component. 408 * This is the absolute index, ignoring layers. 409 * Index numbers, like position numbers, have the topmost component 410 * at index zero. Larger numbers are closer to the bottom. 411 * 412 * @param c the Component to check 413 * @return an int specifying the component's index 414 */ 415 public int getIndexOf(Component c) { 416 int i, count; 417 418 count = getComponentCount(); 419 for(i = 0; i < count; i++) { 420 if(c == getComponent(i)) 421 return i; 422 } 423 return -1; 424 } 425 /** 426 * Moves the component to the top of the components in its current layer 427 * (position 0). 428 * 429 * @param c the Component to move 430 * @see #setPosition(Component, int) 431 */ 432 public void moveToFront(Component c) { 433 setPosition(c, 0); 434 } 435 436 /** 437 * Moves the component to the bottom of the components in its current layer 438 * (position -1). 439 * 440 * @param c the Component to move 441 * @see #setPosition(Component, int) 442 */ 443 public void moveToBack(Component c) { 444 setPosition(c, -1); 445 } 446 447 /** 448 * Moves the component to <code>position</code> within its current layer, 449 * where 0 is the topmost position within the layer and -1 is the bottommost 450 * position. 451 * <p> 452 * <b>Note:</b> Position numbering is defined by java.awt.Container, and 453 * is the opposite of layer numbering. Lower position numbers are closer 454 * to the top (0 is topmost), and higher position numbers are closer to 455 * the bottom. 456 * 457 * @param c the Component to move 458 * @param position an int in the range -1..N-1, where N is the number of 459 * components in the component's current layer 460 */ 461 public void setPosition(Component c, int position) { 462 setLayer(c, getLayer(c), position); 463 } 464 465 /** 466 * Get the relative position of the component within its layer. 467 * 468 * @param c the Component to check 469 * @return an int giving the component's position, where 0 is the 470 * topmost position and the highest index value = the count 471 * count of components at that layer, minus 1 472 * 473 * @see #getComponentCountInLayer 474 */ 475 public int getPosition(Component c) { 476 int i, startLayer, curLayer, startLocation, pos = 0; 477 478 getComponentCount(); 479 startLocation = getIndexOf(c); 480 481 if(startLocation == -1) 482 return -1; 483 484 startLayer = getLayer(c); 485 for(i = startLocation - 1; i >= 0; i--) { 486 curLayer = getLayer(getComponent(i)); 487 if(curLayer == startLayer) 488 pos++; 489 else 490 return pos; 491 } 492 return pos; 493 } 494 495 /** Returns the highest layer value from all current children. 496 * Returns 0 if there are no children. 497 * 498 * @return an int indicating the layer of the topmost component in the 499 * pane, or zero if there are no children 500 */ 501 public int highestLayer() { 502 if(getComponentCount() > 0) 503 return getLayer(getComponent(0)); 504 return 0; 505 } 506 507 /** Returns the lowest layer value from all current children. 508 * Returns 0 if there are no children. 509 * 510 * @return an int indicating the layer of the bottommost component in the 511 * pane, or zero if there are no children 512 */ 513 public int lowestLayer() { 514 int count = getComponentCount(); 515 if(count > 0) 516 return getLayer(getComponent(count-1)); 517 return 0; 518 } 519 520 /** 521 * Returns the number of children currently in the specified layer. 522 * 523 * @param layer an int specifying the layer to check 524 * @return an int specifying the number of components in that layer 525 */ 526 public int getComponentCountInLayer(int layer) { 527 int i, count, curLayer; 528 int layerCount = 0; 529 530 count = getComponentCount(); 531 for(i = 0; i < count; i++) { 532 curLayer = getLayer(getComponent(i)); 533 if(curLayer == layer) { 534 layerCount++; 535 /// Short circut the counting when we have them all 536 } else if(layerCount > 0 || curLayer < layer) { 537 break; 538 } 539 } 540 541 return layerCount; 542 } 543 544 /** 545 * Returns an array of the components in the specified layer. 546 * 547 * @param layer an int specifying the layer to check 548 * @return an array of Components contained in that layer 549 */ 550 public Component[] getComponentsInLayer(int layer) { 551 int i, count, curLayer; 552 int layerCount = 0; 553 Component[] results; 554 555 results = new Component[getComponentCountInLayer(layer)]; 556 count = getComponentCount(); 557 for(i = 0; i < count; i++) { 558 curLayer = getLayer(getComponent(i)); 559 if(curLayer == layer) { 560 results[layerCount++] = getComponent(i); 561 /// Short circut the counting when we have them all 562 } else if(layerCount > 0 || curLayer < layer) { 563 break; 564 } 565 } 566 567 return results; 568 } 569 570 /** 571 * Paints this JLayeredPane within the specified graphics context. 572 * 573 * @param g the Graphics context within which to paint 574 */ 575 public void paint(Graphics g) { 576 if(isOpaque()) { 577 Rectangle r = g.getClipBounds(); 578 Color c = getBackground(); 579 if(c == null) 580 c = Color.lightGray; 581 g.setColor(c); 582 if (r != null) { 583 g.fillRect(r.x, r.y, r.width, r.height); 584 } 585 else { 586 g.fillRect(0, 0, getWidth(), getHeight()); 587 } 588 } 589 super.paint(g); 590 } 591 592 ////////////////////////////////////////////////////////////////////////////// 593 //// Implementation Details 594 ////////////////////////////////////////////////////////////////////////////// 595 596 /** 597 * Returns the hashtable that maps components to layers. 598 * 599 * @return the Hashtable used to map components to their layers 600 */ 601 protected Hashtable<Component,Integer> getComponentToLayer() { 602 if(componentToLayer == null) 603 componentToLayer = new Hashtable<Component,Integer>(4); 604 return componentToLayer; 605 } 606 607 /** 608 * Returns the Integer object associated with a specified layer. 609 * 610 * @param layer an int specifying the layer 611 * @return an Integer object for that layer 612 */ 613 protected Integer getObjectForLayer(int layer) { 614 switch(layer) { 615 case 0: 616 return DEFAULT_LAYER; 617 case 100: 618 return PALETTE_LAYER; 619 case 200: 620 return MODAL_LAYER; 621 case 300: 622 return POPUP_LAYER; 623 case 400: 624 return DRAG_LAYER; 625 default: 626 return layer; 627 } 628 } 629 630 /** 631 * Primitive method that determines the proper location to 632 * insert a new child based on layer and position requests. 633 * 634 * @param layer an int specifying the layer 635 * @param position an int specifying the position within the layer 636 * @return an int giving the (absolute) insertion-index 637 * 638 * @see #getIndexOf 639 */ 640 protected int insertIndexForLayer(int layer, int position) { 641 return insertIndexForLayer(null, layer, position); 642 } 643 644 /** 645 * This method is an extended version of insertIndexForLayer() 646 * to support setLayer which uses Container.setZOrder which does 647 * not remove the component from the containment hierarchy though 648 * we need to ignore it when calculating the insertion index. 649 * 650 * @param comp component to ignore when determining index 651 * @param layer an int specifying the layer 652 * @param position an int specifying the position within the layer 653 * @return an int giving the (absolute) insertion-index 654 * 655 * @see #getIndexOf 656 */ 657 private int insertIndexForLayer(Component comp, int layer, int position) { 658 int i, count, curLayer; 659 int layerStart = -1; 660 int layerEnd = -1; 661 int componentCount = getComponentCount(); 662 663 ArrayList<Component> compList = 664 new ArrayList<Component>(componentCount); 665 for (int index = 0; index < componentCount; index++) { 666 if (getComponent(index) != comp) { 667 compList.add(getComponent(index)); 668 } 669 } 670 671 count = compList.size(); 672 for (i = 0; i < count; i++) { 673 curLayer = getLayer(compList.get(i)); 674 if (layerStart == -1 && curLayer == layer) { 675 layerStart = i; 676 } 677 if (curLayer < layer) { 678 if (i == 0) { 679 // layer is greater than any current layer 680 // [ ASSERT(layer > highestLayer()) ] 681 layerStart = 0; 682 layerEnd = 0; 683 } else { 684 layerEnd = i; 685 } 686 break; 687 } 688 } 689 690 // layer requested is lower than any current layer 691 // [ ASSERT(layer < lowestLayer()) ] 692 // put it on the bottom of the stack 693 if (layerStart == -1 && layerEnd == -1) 694 return count; 695 696 // In the case of a single layer entry handle the degenerative cases 697 if (layerStart != -1 && layerEnd == -1) 698 layerEnd = count; 699 700 if (layerEnd != -1 && layerStart == -1) 701 layerStart = layerEnd; 702 703 // If we are adding to the bottom, return the last element 704 if (position == -1) 705 return layerEnd; 706 707 // Otherwise make sure the requested position falls in the 708 // proper range 709 if (position > -1 && layerStart + position <= layerEnd) 710 return layerStart + position; 711 712 // Otherwise return the end of the layer 713 return layerEnd; 714 } 715 716 /** 717 * Returns a string representation of this JLayeredPane. This method 718 * is intended to be used only for debugging purposes, and the 719 * content and format of the returned string may vary between 720 * implementations. The returned string may be empty but may not 721 * be <code>null</code>. 722 * 723 * @return a string representation of this JLayeredPane. 724 */ 725 protected String paramString() { 726 String optimizedDrawingPossibleString = (optimizedDrawingPossible ? 727 "true" : "false"); 728 729 return super.paramString() + 730 ",optimizedDrawingPossible=" + optimizedDrawingPossibleString; 731 } 732 733 ///////////////// 734 // Accessibility support 735 //////////////// 736 737 /** 738 * Gets the AccessibleContext associated with this JLayeredPane. 739 * For layered panes, the AccessibleContext takes the form of an 740 * AccessibleJLayeredPane. 741 * A new AccessibleJLayeredPane instance is created if necessary. 742 * 743 * @return an AccessibleJLayeredPane that serves as the 744 * AccessibleContext of this JLayeredPane 745 */ 746 @BeanProperty(bound = false) 747 public AccessibleContext getAccessibleContext() { 748 if (accessibleContext == null) { 749 accessibleContext = new AccessibleJLayeredPane(); 750 } 751 return accessibleContext; 752 } 753 754 /** 755 * This class implements accessibility support for the 756 * <code>JLayeredPane</code> class. It provides an implementation of the 757 * Java Accessibility API appropriate to layered pane user-interface 758 * elements. 759 * <p> 760 * <strong>Warning:</strong> 761 * Serialized objects of this class will not be compatible with 762 * future Swing releases. The current serialization support is 763 * appropriate for short term storage or RMI between applications running 764 * the same version of Swing. As of 1.4, support for long term storage 765 * of all JavaBeans™ 766 * has been added to the <code>java.beans</code> package. 767 * Please see {@link java.beans.XMLEncoder}. 768 */ 769 @SuppressWarnings("serial") 770 protected class AccessibleJLayeredPane extends AccessibleJComponent { 771 772 /** 773 * Get the role of this object. 774 * 775 * @return an instance of AccessibleRole describing the role of the 776 * object 777 * @see AccessibleRole 778 */ 779 public AccessibleRole getAccessibleRole() { 780 return AccessibleRole.LAYERED_PANE; 781 } 782 } 783 }