1 /*
   2  * Copyright (c) 2009, 2014, 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 
  26 package javax.swing.plaf;
  27 
  28 import javax.swing.*;
  29 import java.awt.*;
  30 import java.awt.event.*;
  31 import java.beans.PropertyChangeEvent;
  32 import java.beans.PropertyChangeSupport;
  33 import java.beans.PropertyChangeListener;
  34 import java.io.Serializable;
  35 
  36 /**
  37  * The base class for all {@link javax.swing.JLayer}'s UI delegates.
  38  * <p>
  39  * {@link #paint(java.awt.Graphics, javax.swing.JComponent)} method performs the
  40  * painting of the {@code JLayer}
  41  * and {@link #eventDispatched(AWTEvent, JLayer)} method is notified
  42  * about any {@code AWTEvent}s which have been generated by a {@code JLayer}
  43  * or any of its subcomponents.
  44  * <p>
  45  * The {@code LayerUI} differs from the UI delegates of the other components,
  46  * because it is LookAndFeel independent and is not updated by default when
  47  * the system LookAndFeel is changed.
  48  * <p>
  49  * The subclasses of {@code LayerUI} can either be stateless and shareable
  50  * by multiple {@code JLayer}s or not shareable.
  51  *
  52  * @param <V> one of the super types of {@code JLayer}'s view component
  53  *
  54  * @see JLayer#setUI(LayerUI)
  55  * @see JLayer#setView(Component)
  56  * @see JLayer#getView()
  57  * @since 1.7
  58  *
  59  * @author Alexander Potochkin
  60  */
  61 @SuppressWarnings("serial") // Same-version serialization only
  62 public class LayerUI<V extends Component>
  63         extends ComponentUI implements Serializable {
  64 
  65     private final PropertyChangeSupport propertyChangeSupport =
  66             new PropertyChangeSupport(this);
  67 
  68     /**
  69      * Paints the specified component.
  70      * Subclasses should override this method and use
  71      * the specified {@code Graphics} object to
  72      * render the content of the component.
  73      * <p>
  74      * The default implementation paints the passed component as is.
  75      *
  76      * @param g the {@code Graphics} context in which to paint
  77      * @param c the component being painted
  78      */
  79     public void paint(Graphics g, JComponent c) {
  80         c.paint(g);
  81     }
  82 
  83     /**
  84      * Processes {@code AWTEvent}s for {@code JLayer}
  85      * and <b>all its descendants</b> to this {@code LayerUI} instance.
  86      * <p>
  87      * To enable the {@code AWTEvent}s of a particular type,
  88      * you call {@link JLayer#setLayerEventMask}
  89      * in {@link #installUI(javax.swing.JComponent)}
  90      * and set the layer event mask to {@code 0}
  91      * in {@link #uninstallUI(javax.swing.JComponent)} after that.
  92      * By default this  method calls the appropriate
  93      * {@code process&lt;event&nbsp;type&gt;Event}
  94      * method for the given class of event.
  95      * <p>
  96      * <b>Note:</b> Events are processed only for displayable {@code JLayer}s.
  97      *
  98      * @param e the event to be dispatched
  99      * @param l the layer this LayerUI is set to
 100      *
 101      * @see JLayer#setLayerEventMask(long)
 102      * @see Component#isDisplayable()
 103      * @see #processComponentEvent
 104      * @see #processFocusEvent
 105      * @see #processKeyEvent
 106      * @see #processMouseEvent
 107      * @see #processMouseMotionEvent
 108      * @see #processInputMethodEvent
 109      * @see #processHierarchyEvent
 110      * @see #processMouseWheelEvent
 111      */
 112     public void eventDispatched(AWTEvent e, JLayer<? extends V> l){
 113         if (e instanceof FocusEvent) {
 114             processFocusEvent((FocusEvent)e, l);
 115 
 116         } else if (e instanceof MouseEvent) {
 117             switch(e.getID()) {
 118               case MouseEvent.MOUSE_PRESSED:
 119               case MouseEvent.MOUSE_RELEASED:
 120               case MouseEvent.MOUSE_CLICKED:
 121               case MouseEvent.MOUSE_ENTERED:
 122               case MouseEvent.MOUSE_EXITED:
 123                   processMouseEvent((MouseEvent)e, l);
 124                   break;
 125               case MouseEvent.MOUSE_MOVED:
 126               case MouseEvent.MOUSE_DRAGGED:
 127                   processMouseMotionEvent((MouseEvent)e, l);
 128                   break;
 129               case MouseEvent.MOUSE_WHEEL:
 130                   processMouseWheelEvent((MouseWheelEvent)e, l);
 131                   break;
 132             }
 133         } else if (e instanceof KeyEvent) {
 134             processKeyEvent((KeyEvent)e, l);
 135         } else if (e instanceof ComponentEvent) {
 136             processComponentEvent((ComponentEvent)e, l);
 137         } else if (e instanceof InputMethodEvent) {
 138             processInputMethodEvent((InputMethodEvent)e, l);
 139         } else if (e instanceof HierarchyEvent) {
 140             switch (e.getID()) {
 141               case HierarchyEvent.HIERARCHY_CHANGED:
 142                   processHierarchyEvent((HierarchyEvent)e, l);
 143                   break;
 144               case HierarchyEvent.ANCESTOR_MOVED:
 145               case HierarchyEvent.ANCESTOR_RESIZED:
 146                   processHierarchyBoundsEvent((HierarchyEvent)e, l);
 147                   break;
 148             }
 149         }
 150     }
 151 
 152     /**
 153      * Processes component events occurring on the {@link JLayer}
 154      * or any of its subcomponents.
 155      * <p>
 156      * This method is not called unless component events are
 157      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 158      * Component events are enabled in the overridden {@link #installUI} method
 159      * and should be disabled in the {@link #uninstallUI} method after that.
 160      * <pre>
 161      * public void installUI(JComponent c) {
 162      *    super.installUI(c);
 163      *    JLayer l = (JLayer) c;
 164      *    l.setLayerEventMask(AWTEvent.COMPONENT_EVENT_MASK);
 165      * }
 166      *
 167      * public void uninstallUI(JComponent c) {
 168      *     super.uninstallUI(c);
 169      *     JLayer l = (JLayer) c;
 170      *     l.setLayerEventMask(0);
 171      * }
 172      * </pre>
 173      *
 174      * @param e the {@code ComponentEvent} to be processed
 175      * @param l the layer this {@code LayerUI} instance is set to
 176      *
 177      * @see JLayer#setLayerEventMask(long)
 178      * @see #installUI(javax.swing.JComponent)
 179      * @see #uninstallUI(javax.swing.JComponent)
 180      */
 181     protected void processComponentEvent(ComponentEvent e, JLayer<? extends V> l) {
 182     }
 183 
 184     /**
 185      * Processes focus events occurring on the {@link JLayer}
 186      * or any of its subcomponents.
 187      * <p>
 188      * This method is not called unless focus events are
 189      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 190      * Focus events are enabled in the overridden {@link #installUI} method
 191      * and should be disabled in the {@link #uninstallUI} method after that.
 192      * <pre>
 193      * public void installUI(JComponent c) {
 194      *    super.installUI(c);
 195      *    JLayer l = (JLayer) c;
 196      *    l.setLayerEventMask(AWTEvent.FOCUS_EVENT_MASK);
 197      * }
 198      *
 199      * public void uninstallUI(JComponent c) {
 200      *     super.uninstallUI(c);
 201      *     JLayer l = (JLayer) c;
 202      *     l.setLayerEventMask(0);
 203      * }
 204      * </pre>
 205      *
 206      * @param e the {@code FocusEvent} to be processed
 207      * @param l the layer this {@code LayerUI} instance is set to
 208      *
 209      * @see JLayer#setLayerEventMask(long)
 210      * @see #installUI(javax.swing.JComponent)
 211      * @see #uninstallUI(javax.swing.JComponent)
 212      */
 213     protected void processFocusEvent(FocusEvent e, JLayer<? extends V> l) {
 214     }
 215 
 216     /**
 217      * Processes key events occurring on the {@link JLayer}
 218      * or any of its subcomponents.
 219      * <p>
 220      * This method is not called unless key events are
 221      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 222      * Key events are enabled in the overridden {@link #installUI} method
 223      * and should be disabled in the {@link #uninstallUI} method after that.
 224      * <pre>
 225      * public void installUI(JComponent c) {
 226      *    super.installUI(c);
 227      *    JLayer l = (JLayer) c;
 228      *    l.setLayerEventMask(AWTEvent.KEY_EVENT_MASK);
 229      * }
 230      *
 231      * public void uninstallUI(JComponent c) {
 232      *     super.uninstallUI(c);
 233      *     JLayer l = (JLayer) c;
 234      *     l.setLayerEventMask(0);
 235      * }
 236      * </pre>
 237      *
 238      * @param e the {@code KeyEvent} to be processed
 239      * @param l the layer this {@code LayerUI} instance is set to
 240      *
 241      * @see JLayer#setLayerEventMask(long)
 242      * @see #installUI(javax.swing.JComponent)
 243      * @see #uninstallUI(javax.swing.JComponent)
 244      */
 245     protected void processKeyEvent(KeyEvent e, JLayer<? extends V> l) {
 246     }
 247 
 248     /**
 249      * Processes mouse events occurring on the {@link JLayer}
 250      * or any of its subcomponents.
 251      * <p>
 252      * This method is not called unless mouse events are
 253      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 254      * Mouse events are enabled in the overridden {@link #installUI} method
 255      * and should be disabled in the {@link #uninstallUI} method after that.
 256      * <pre>
 257      * public void installUI(JComponent c) {
 258      *    super.installUI(c);
 259      *    JLayer l = (JLayer) c;
 260      *    l.setLayerEventMask(AWTEvent.MOUSE_EVENT_MASK);
 261      * }
 262      *
 263      * public void uninstallUI(JComponent c) {
 264      *     super.uninstallUI(c);
 265      *     JLayer l = (JLayer) c;
 266      *     l.setLayerEventMask(0);
 267      * }
 268      * </pre>
 269      *
 270      * @param e the {@code MouseEvent} to be processed
 271      * @param l the layer this {@code LayerUI} instance is set to
 272      *
 273      * @see JLayer#setLayerEventMask(long)
 274      * @see #installUI(javax.swing.JComponent)
 275      * @see #uninstallUI(javax.swing.JComponent)
 276      */
 277     protected void processMouseEvent(MouseEvent e, JLayer<? extends V> l) {
 278     }
 279 
 280     /**
 281      * Processes mouse motion event occurring on the {@link JLayer}
 282      * or any of its subcomponents.
 283      * <p>
 284      * This method is not called unless mouse motion events are
 285      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 286      * Mouse motion events are enabled in the overridden {@link #installUI} method
 287      * and should be disabled in the {@link #uninstallUI} method after that.
 288      * <pre>
 289      * public void installUI(JComponent c) {
 290      *    super.installUI(c);
 291      *    JLayer l = (JLayer) c;
 292      *    l.setLayerEventMask(AWTEvent.MOUSE_MOTION_EVENT_MASK);
 293      * }
 294      *
 295      * public void uninstallUI(JComponent c) {
 296      *     super.uninstallUI(c);
 297      *     JLayer l = (JLayer) c;
 298      *     l.setLayerEventMask(0);
 299      * }
 300      * </pre>
 301      *
 302      * @param e the {@code MouseEvent} to be processed
 303      * @param l the layer this {@code LayerUI} instance is set to
 304      *
 305      * @see JLayer#setLayerEventMask(long)
 306      * @see #installUI(javax.swing.JComponent)
 307      * @see #uninstallUI(javax.swing.JComponent)
 308      */
 309     protected void processMouseMotionEvent(MouseEvent e, JLayer<? extends V> l) {
 310     }
 311 
 312     /**
 313      * Processes mouse wheel event occurring on the {@link JLayer}
 314      * or any of its subcomponents.
 315      * <p>
 316      * This method is not called unless mouse wheel events are
 317      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 318      * Mouse wheel events are enabled in the overridden {@link #installUI} method
 319      * and should be disabled in the {@link #uninstallUI} method after that.
 320      * <pre>
 321      * public void installUI(JComponent c) {
 322      *    super.installUI(c);
 323      *    JLayer l = (JLayer) c;
 324      *    l.setLayerEventMask(AWTEvent.MOUSE_WHEEL_EVENT_MASK);
 325      * }
 326      *
 327      * public void uninstallUI(JComponent c) {
 328      *     super.uninstallUI(c);
 329      *     JLayer l = (JLayer) c;
 330      *     l.setLayerEventMask(0);
 331      * }
 332      * </pre>
 333      *
 334      * @param e the {@code MouseEvent} to be processed
 335      * @param l the layer this {@code LayerUI} instance is set to
 336      *
 337      * @see JLayer#setLayerEventMask(long)
 338      * @see #installUI(javax.swing.JComponent)
 339      * @see #uninstallUI(javax.swing.JComponent)
 340      */
 341     protected void processMouseWheelEvent(MouseWheelEvent e, JLayer<? extends V> l) {
 342     }
 343 
 344     /**
 345      * Processes input event occurring on the {@link JLayer}
 346      * or any of its subcomponents.
 347      * <p>
 348      * This method is not called unless input events are
 349      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 350      * Input events are enabled in the overridden {@link #installUI} method
 351      * and should be disabled in the {@link #uninstallUI} method after that.
 352      * <pre>
 353      * public void installUI(JComponent c) {
 354      *    super.installUI(c);
 355      *    JLayer l = (JLayer) c;
 356      *    l.setLayerEventMask(AWTEvent.INPUT_METHOD_EVENT_MASK);
 357      * }
 358      *
 359      * public void uninstallUI(JComponent c) {
 360      *     super.uninstallUI(c);
 361      *     JLayer l = (JLayer) c;
 362      *     l.setLayerEventMask(0);
 363      * }
 364      * </pre>
 365      *
 366      * @param e the {@code InputMethodEvent} to be processed
 367      * @param l the layer this {@code LayerUI} instance is set to
 368      *
 369      * @see JLayer#setLayerEventMask(long)
 370      * @see #installUI(javax.swing.JComponent)
 371      * @see #uninstallUI(javax.swing.JComponent)
 372      */
 373     protected void processInputMethodEvent(InputMethodEvent e, JLayer<? extends V> l) {
 374     }
 375 
 376     /**
 377      * Processes hierarchy event occurring on the {@link JLayer}
 378      * or any of its subcomponents.
 379      * <p>
 380      * This method is not called unless hierarchy events are
 381      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 382      * Hierarchy events are enabled in the overridden {@link #installUI} method
 383      * and should be disabled in the {@link #uninstallUI} method after that.
 384      * <pre>
 385      * public void installUI(JComponent c) {
 386      *    super.installUI(c);
 387      *    JLayer l = (JLayer) c;
 388      *    l.setLayerEventMask(AWTEvent.HIERARCHY_EVENT_MASK);
 389      * }
 390      *
 391      * public void uninstallUI(JComponent c) {
 392      *     super.uninstallUI(c);
 393      *     JLayer l = (JLayer) c;
 394      *     l.setLayerEventMask(0);
 395      * }
 396      * </pre>
 397      *
 398      * @param e the {@code HierarchyEvent} to be processed
 399      * @param l the layer this {@code LayerUI} instance is set to
 400      *
 401      * @see JLayer#setLayerEventMask(long)
 402      * @see #installUI(javax.swing.JComponent)
 403      * @see #uninstallUI(javax.swing.JComponent)
 404      */
 405     protected void processHierarchyEvent(HierarchyEvent e, JLayer<? extends V> l) {
 406     }
 407 
 408     /**
 409      * Processes hierarchy bounds event occurring on the {@link JLayer}
 410      * or any of its subcomponents.
 411      * <p>
 412      * This method is not called unless hierarchy bounds events are
 413      * enabled for the {@code JLayer} objects, this {@code LayerUI} is set to.
 414      * Hierarchy bounds events are enabled in the overridden {@link #installUI}
 415      * method and should be disabled in the {@link #uninstallUI} method after that.
 416      * <pre>
 417      * public void installUI(JComponent c) {
 418      *    super.installUI(c);
 419      *    JLayer l = (JLayer) c;
 420      *    l.setLayerEventMask(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK);
 421      * }
 422      *
 423      * public void uninstallUI(JComponent c) {
 424      *     super.uninstallUI(c);
 425      *     JLayer l = (JLayer) c;
 426      *     l.setLayerEventMask(0);
 427      * }
 428      * </pre>
 429      *
 430      * @param e the {@code HierarchyEvent} to be processed
 431      * @param l the layer this {@code LayerUI} instance is set to
 432      *
 433      * @see JLayer#setLayerEventMask(long)
 434      * @see #installUI(javax.swing.JComponent)
 435      * @see #uninstallUI(javax.swing.JComponent)
 436      */
 437     protected void processHierarchyBoundsEvent(HierarchyEvent e, JLayer<? extends V> l) {
 438     }
 439 
 440     /**
 441      * Invoked when {@link javax.swing.JLayer#updateUI()} is called
 442      * by the {@code JLayer} this {@code LayerUI} is set to.
 443      *
 444      * @param l the {@code JLayer} which UI is updated
 445      */
 446     public void updateUI(JLayer<? extends V> l){
 447     }
 448 
 449     /**
 450      * Configures the {@code JLayer} this {@code LayerUI} is set to.
 451      * The default implementation registers the passed {@code JLayer} component
 452      * as a {@code PropertyChangeListener} for the property changes of this {@code LayerUI}.
 453      *
 454      * @param c the {@code JLayer} component where this UI delegate is being installed
 455      */
 456     public void installUI(JComponent c) {
 457         addPropertyChangeListener((JLayer) c);
 458     }
 459 
 460     /**
 461      * Reverses the configuration which was previously set
 462      * in the {@link #installUI(JComponent)} method.
 463      * The default implementation unregisters the passed {@code JLayer} component
 464      * as a {@code PropertyChangeListener} for the property changes of this {@code LayerUI}.
 465      *
 466      * @param c the component from which this UI delegate is being removed.
 467      */
 468     public void uninstallUI(JComponent c) {
 469         removePropertyChangeListener((JLayer) c);
 470     }
 471 
 472     /**
 473      * Adds a PropertyChangeListener to the listener list. The listener is
 474      * registered for all bound properties of this class.
 475      * <p>
 476      * If {@code listener} is {@code null},
 477      * no exception is thrown and no action is performed.
 478      *
 479      * @param listener the property change listener to be added
 480      * @see #removePropertyChangeListener
 481      * @see #getPropertyChangeListeners
 482      * @see #addPropertyChangeListener(String, java.beans.PropertyChangeListener)
 483      */
 484     public void addPropertyChangeListener(PropertyChangeListener listener) {
 485         propertyChangeSupport.addPropertyChangeListener(listener);
 486     }
 487 
 488     /**
 489      * Removes a PropertyChangeListener from the listener list. This method
 490      * should be used to remove PropertyChangeListeners that were registered
 491      * for all bound properties of this class.
 492      * <p>
 493      * If {@code listener} is {@code null},
 494      * no exception is thrown and no action is performed.
 495      *
 496      * @param listener the PropertyChangeListener to be removed
 497      * @see #addPropertyChangeListener
 498      * @see #getPropertyChangeListeners
 499      * @see #removePropertyChangeListener(String, PropertyChangeListener)
 500      */
 501     public void removePropertyChangeListener(PropertyChangeListener listener) {
 502         propertyChangeSupport.removePropertyChangeListener(listener);
 503     }
 504 
 505     /**
 506      * Returns an array of all the property change listeners
 507      * registered on this component.
 508      *
 509      * @return all of this ui's {@code PropertyChangeListener}s
 510      *         or an empty array if no property change
 511      *         listeners are currently registered
 512      * @see #addPropertyChangeListener
 513      * @see #removePropertyChangeListener
 514      * @see #getPropertyChangeListeners(String)
 515      */
 516     public PropertyChangeListener[] getPropertyChangeListeners() {
 517         return propertyChangeSupport.getPropertyChangeListeners();
 518     }
 519 
 520     /**
 521      * Adds a PropertyChangeListener to the listener list for a specific
 522      * property.
 523      * <p>
 524      * If {@code propertyName} or {@code listener} is {@code null},
 525      * no exception is thrown and no action is taken.
 526      *
 527      * @param propertyName one of the property names listed above
 528      * @param listener     the property change listener to be added
 529      * @see #removePropertyChangeListener(String, PropertyChangeListener)
 530      * @see #getPropertyChangeListeners(String)
 531      * @see #addPropertyChangeListener(String, PropertyChangeListener)
 532      */
 533     public void addPropertyChangeListener(String propertyName,
 534                                           PropertyChangeListener listener) {
 535         propertyChangeSupport.addPropertyChangeListener(propertyName, listener);
 536     }
 537 
 538     /**
 539      * Removes a {@code PropertyChangeListener} from the listener
 540      * list for a specific property. This method should be used to remove
 541      * {@code PropertyChangeListener}s
 542      * that were registered for a specific bound property.
 543      * <p>
 544      * If {@code propertyName} or {@code listener} is {@code null},
 545      * no exception is thrown and no action is taken.
 546      *
 547      * @param propertyName a valid property name
 548      * @param listener     the PropertyChangeListener to be removed
 549      * @see #addPropertyChangeListener(String, PropertyChangeListener)
 550      * @see #getPropertyChangeListeners(String)
 551      * @see #removePropertyChangeListener(PropertyChangeListener)
 552      */
 553     public void removePropertyChangeListener(String propertyName,
 554                                              PropertyChangeListener listener) {
 555         propertyChangeSupport.removePropertyChangeListener(propertyName, listener);
 556     }
 557 
 558     /**
 559      * Returns an array of all the listeners which have been associated
 560      * with the named property.
 561      *
 562      * @param propertyName  The name of the property being listened to
 563      * @return all of the {@code PropertyChangeListener}s associated with
 564      *         the named property; if no such listeners have been added or
 565      *         if {@code propertyName} is {@code null}, an empty
 566      *         array is returned
 567      * @see #addPropertyChangeListener(String, PropertyChangeListener)
 568      * @see #removePropertyChangeListener(String, PropertyChangeListener)
 569      * @see #getPropertyChangeListeners
 570      */
 571     public PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
 572         return propertyChangeSupport.getPropertyChangeListeners(propertyName);
 573     }
 574 
 575     /**
 576      * Support for reporting bound property changes for Object properties.
 577      * This method can be called when a bound property has changed and it will
 578      * send the appropriate PropertyChangeEvent to any registered
 579      * PropertyChangeListeners.
 580      *
 581      * @param propertyName the property whose value has changed
 582      * @param oldValue     the property's previous value
 583      * @param newValue     the property's new value
 584      */
 585     protected void firePropertyChange(String propertyName,
 586                                       Object oldValue, Object newValue) {
 587         propertyChangeSupport.firePropertyChange(propertyName, oldValue, newValue);
 588     }
 589 
 590     /**
 591      * Notifies the {@code LayerUI} when any of its property are changed
 592      * and enables updating every {@code JLayer}
 593      * this {@code LayerUI} instance is set to.
 594      *
 595      * @param evt the PropertyChangeEvent generated by this {@code LayerUI}
 596      * @param l the {@code JLayer} this LayerUI is set to
 597      */
 598     public void applyPropertyChange(PropertyChangeEvent evt, JLayer<? extends V> l) {
 599     }
 600 
 601     /**
 602      * If the {@code JLayer}'s view component is not {@code null},
 603      * this calls the view's {@code getBaseline()} method.
 604      * Otherwise, the default implementation is called.
 605      *
 606      * @param c {@code JLayer} to return baseline resize behavior for
 607      * @param width the width to get the baseline for
 608      * @param height the height to get the baseline for
 609      * @return baseline or a value &lt; 0 indicating there is no reasonable
 610      *                  baseline
 611      */
 612     public int getBaseline(JComponent c, int width, int height) {
 613         @SuppressWarnings("unchecked")
 614         JLayer<?> l = (JLayer) c;
 615         if (l.getView() != null) {
 616             return l.getView().getBaseline(width, height);
 617         }
 618         return super.getBaseline(c, width, height);
 619      }
 620 
 621     /**
 622      * If the {@code JLayer}'s view component is not {@code null},
 623      * this returns the result of the view's {@code getBaselineResizeBehavior()} method.
 624      * Otherwise, the default implementation is called.
 625      *
 626      * @param c {@code JLayer} to return baseline resize behavior for
 627      * @return an enum indicating how the baseline changes as the component
 628      *         size changes
 629      */
 630     public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c) {
 631         @SuppressWarnings("unchecked")
 632         JLayer<?> l = (JLayer) c;
 633         if (l.getView() != null) {
 634             return l.getView().getBaselineResizeBehavior();
 635         }
 636         return super.getBaselineResizeBehavior(c);
 637     }
 638 
 639     /**
 640      * Causes the passed instance of {@code JLayer} to lay out its components.
 641      *
 642      * @param l the {@code JLayer} component where this UI delegate is being installed
 643      */
 644     public void doLayout(JLayer<? extends V> l) {
 645         Component view = l.getView();
 646         if (view != null) {
 647             view.setBounds(0, 0, l.getWidth(), l.getHeight());
 648         }
 649         Component glassPane = l.getGlassPane();
 650         if (glassPane != null) {
 651             glassPane.setBounds(0, 0, l.getWidth(), l.getHeight());
 652         }
 653     }
 654 
 655     /**
 656      * If the {@code JLayer}'s view component is not {@code null},
 657      * this returns the result of  the view's {@code getPreferredSize()} method.
 658      * Otherwise, the default implementation is used.
 659      *
 660      * @param c {@code JLayer} to return preferred size for
 661      * @return preferred size for the passed {@code JLayer}
 662      */
 663     public Dimension getPreferredSize(JComponent c) {
 664         @SuppressWarnings("unchecked")
 665         JLayer<?> l = (JLayer) c;
 666         Component view = l.getView();
 667         if (view != null) {
 668             return view.getPreferredSize();
 669         }
 670         return super.getPreferredSize(c);
 671     }
 672 
 673     /**
 674      * If the {@code JLayer}'s view component is not {@code null},
 675      * this returns the result of  the view's {@code getMinimalSize()} method.
 676      * Otherwise, the default implementation is used.
 677      *
 678      * @param c {@code JLayer} to return preferred size for
 679      * @return minimal size for the passed {@code JLayer}
 680      */
 681     public Dimension getMinimumSize(JComponent c) {
 682         @SuppressWarnings("unchecked")
 683         JLayer<?> l = (JLayer) c;
 684         Component view = l.getView();
 685         if (view != null) {
 686             return view.getMinimumSize();
 687         }
 688         return super.getMinimumSize(c);
 689     }
 690 
 691     /**
 692      * If the {@code JLayer}'s view component is not {@code null},
 693      * this returns the result of  the view's {@code getMaximumSize()} method.
 694      * Otherwise, the default implementation is used.
 695      *
 696      * @param c {@code JLayer} to return preferred size for
 697      * @return maximum size for the passed {@code JLayer}
 698      */
 699     public Dimension getMaximumSize(JComponent c) {
 700         @SuppressWarnings("unchecked")
 701         JLayer<?> l = (JLayer) c;
 702         Component view = l.getView();
 703         if (view != null) {
 704             return view.getMaximumSize();
 705         }
 706         return super.getMaximumSize(c);
 707     }
 708 
 709     /**
 710      * Paints the specified region in the {@code JLayer} this {@code LayerUI} is set to, immediately.
 711      * <p>
 712      * This method is to be overridden when the dirty region needs to be changed.
 713      * The default implementation delegates its functionality to {@link JComponent#paintImmediately(int, int, int, int)}.
 714      *
 715      * @param x  the x value of the region to be painted
 716      * @param y  the y value of the region to be painted
 717      * @param width  the width of the region to be painted
 718      * @param height  the height of the region to be painted
 719      *
 720      * @see JComponent#paintImmediately(int, int, int, int)
 721      */
 722     public void paintImmediately(int x, int y, int width, int height, JLayer<? extends V> l) {
 723         l.paintImmediately(x, y, width, height);
 724     }
 725 }