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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2011, 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 java.beans; | ||
| 26 | |||
| 27 | import java.io.Serializable; | ||
| 28 | import java.io.ObjectStreamField; | ||
| 29 | import java.io.ObjectOutputStream; | ||
| 30 | import java.io.ObjectInputStream; | ||
| 31 | import java.io.IOException; | ||
| 32 | import java.util.Hashtable; | ||
| 33 | import java.util.Map.Entry; | ||
| 34 | |||
| 35 | /** | ||
| 36 | * This is a utility class that can be used by beans that support constrained | ||
| 37 | * properties. It manages a list of listeners and dispatches | ||
| 38 | * {@link PropertyChangeEvent}s to them. You can use an instance of this class | ||
| 39 | * as a member field of your bean and delegate these types of work to it. | ||
| 40 | * The {@link VetoableChangeListener} can be registered for all properties | ||
| 41 | * or for a property specified by name. | ||
| 42 | * <p> | ||
| 43 | * Here is an example of {@code VetoableChangeSupport} usage that follows | ||
| 44 | * the rules and recommendations laid out in the JavaBeans™ specification: | ||
| 45 | * <pre> | ||
| 46 | * public class MyBean { | ||
| 47 | * private final VetoableChangeSupport vcs = new VetoableChangeSupport(this); | ||
| 48 | * | ||
| 49 | * public void addVetoableChangeListener(VetoableChangeListener listener) { | ||
| 50 | * this.vcs.addVetoableChangeListener(listener); | ||
| 51 | * } | ||
| 52 | * | ||
| 53 | * public void removeVetoableChangeListener(VetoableChangeListener listener) { | ||
| 54 | * this.vcs.removeVetoableChangeListener(listener); | ||
| 55 | * } | ||
| 56 | * | ||
| 57 | * private String value; | ||
| 58 | * | ||
| 59 | * public String getValue() { | ||
| 60 | * return this.value; | ||
| 61 | * } | ||
| 62 | * | ||
| 63 | * public void setValue(String newValue) throws PropertyVetoException { | ||
| 64 | * String oldValue = this.value; | ||
| 65 | * this.vcs.fireVetoableChange("value", oldValue, newValue); | ||
| 66 | * this.value = newValue; | ||
| 67 | * } | ||
| 68 | * | ||
| 69 | * [...] | ||
| 70 | * } | ||
| 71 | * </pre> | ||
| 72 | * <p> | ||
| 73 | * A {@code VetoableChangeSupport} instance is thread-safe. | ||
| 74 | * <p> | ||
| 75 | * This class is serializable. When it is serialized it will save | ||
| 76 | * (and restore) any listeners that are themselves serializable. Any | ||
| 77 | * non-serializable listeners will be skipped during serialization. | ||
| 78 | * | ||
| 79 | * @see PropertyChangeSupport | ||
| 80 | */ | ||
| 81 | public class VetoableChangeSupport implements Serializable { | ||
| 82 | private VetoableChangeListenerMap map = new VetoableChangeListenerMap(); | ||
| 83 | |||
| 84 | /** | ||
| 85 | * Constructs a <code>VetoableChangeSupport</code> object. | ||
| 86 | * | ||
| 87 | * @param sourceBean The bean to be given as the source for any events. | ||
| 88 | */ | ||
| 89 | public VetoableChangeSupport(Object sourceBean) { | ||
| 90 | if (sourceBean == null) { | ||
| 91 | throw new NullPointerException(); | ||
| 92 | } | ||
| 93 | source = sourceBean; | ||
| 94 | } | ||
| 95 | |||
| 96 | /** | ||
| 97 | * Add a VetoableChangeListener to the listener list. | ||
| 98 | * The listener is registered for all properties. | ||
| 99 | * The same listener object may be added more than once, and will be called | ||
| 100 | * as many times as it is added. | ||
| 101 | * If <code>listener</code> is null, no exception is thrown and no action | ||
| 102 | * is taken. | ||
| 103 | * | ||
| 104 | * @param listener The VetoableChangeListener to be added | ||
| 105 | */ | ||
| 106 | public void addVetoableChangeListener(VetoableChangeListener listener) { | ||
| 107 | if (listener == null) { | ||
| 108 | return; | ||
| 109 | } | ||
| 110 | if (listener instanceof VetoableChangeListenerProxy) { | ||
| 111 | VetoableChangeListenerProxy proxy = | ||
| 112 | (VetoableChangeListenerProxy)listener; | ||
| 113 | // Call two argument add method. | ||
| 114 | addVetoableChangeListener(proxy.getPropertyName(), | ||
| 115 | proxy.getListener()); | ||
| 116 | } else { | ||
| 117 | this.map.add(null, listener); | ||
| 118 | } | ||
| 119 | } | ||
| 120 | |||
| 121 | /** | ||
| 122 | * Remove a VetoableChangeListener from the listener list. | ||
| 123 | * This removes a VetoableChangeListener that was registered | ||
| 124 | * for all properties. | ||
| 125 | * If <code>listener</code> was added more than once to the same event | ||
| 126 | * source, it will be notified one less time after being removed. | ||
| 127 | * If <code>listener</code> is null, or was never added, no exception is | ||
| 128 | * thrown and no action is taken. | ||
| 129 | * | ||
| 130 | * @param listener The VetoableChangeListener to be removed | ||
| 131 | */ | ||
| 132 | public void removeVetoableChangeListener(VetoableChangeListener listener) { | ||
| 133 | if (listener == null) { | ||
| 134 | return; | ||
| 135 | } | ||
| 136 | if (listener instanceof VetoableChangeListenerProxy) { | ||
| 137 | VetoableChangeListenerProxy proxy = | ||
| 138 | (VetoableChangeListenerProxy)listener; | ||
| 139 | // Call two argument remove method. | ||
| 140 | removeVetoableChangeListener(proxy.getPropertyName(), | ||
| 141 | proxy.getListener()); | ||
| 142 | } else { | ||
| 143 | this.map.remove(null, listener); | ||
| 144 | } | ||
| 145 | } | ||
| 146 | |||
| 147 | /** | ||
| 148 | * Returns an array of all the listeners that were added to the | ||
| 149 | * VetoableChangeSupport object with addVetoableChangeListener(). | ||
| 150 | * <p> | ||
| 151 | * If some listeners have been added with a named property, then | ||
| 152 | * the returned array will be a mixture of VetoableChangeListeners | ||
| 153 | * and <code>VetoableChangeListenerProxy</code>s. If the calling | ||
| 154 | * method is interested in distinguishing the listeners then it must | ||
| 155 | * test each element to see if it's a | ||
| 156 | * <code>VetoableChangeListenerProxy</code>, perform the cast, and examine | ||
| 157 | * the parameter. | ||
| 158 | * | ||
| 159 | * <pre> | ||
| 160 | * VetoableChangeListener[] listeners = bean.getVetoableChangeListeners(); | ||
| 161 | * for (int i = 0; i < listeners.length; i++) { | ||
| 162 | * if (listeners[i] instanceof VetoableChangeListenerProxy) { | ||
| 163 | * VetoableChangeListenerProxy proxy = | ||
| 164 | * (VetoableChangeListenerProxy)listeners[i]; | ||
| 165 | * if (proxy.getPropertyName().equals("foo")) { | ||
| 166 | * // proxy is a VetoableChangeListener which was associated | ||
| 167 | * // with the property named "foo" | ||
| 168 | * } | ||
| 169 | * } | ||
| 170 | * } | ||
| 171 | *</pre> | ||
| 172 | * | ||
| 173 | * @see VetoableChangeListenerProxy | ||
| 174 | * @return all of the <code>VetoableChangeListeners</code> added or an | ||
| 175 | * empty array if no listeners have been added | ||
| 176 | * @since 1.4 | ||
| 177 | */ | ||
| 178 | public VetoableChangeListener[] getVetoableChangeListeners(){ | ||
| 179 | return this.map.getListeners(); | ||
| 180 | } | ||
| 181 | |||
| 182 | /** | ||
| 183 | * Add a VetoableChangeListener for a specific property. The listener | ||
| 184 | * will be invoked only when a call on fireVetoableChange names that | ||
| 185 | * specific property. | ||
| 186 | * The same listener object may be added more than once. For each | ||
| 187 | * property, the listener will be invoked the number of times it was added | ||
| 188 | * for that property. | ||
| 189 | * If <code>propertyName</code> or <code>listener</code> is null, no | ||
| 190 | * exception is thrown and no action is taken. | ||
| 191 | * | ||
| 192 | * @param propertyName The name of the property to listen on. | ||
| 193 | * @param listener The VetoableChangeListener to be added | ||
| 194 | */ | ||
| 195 | public void addVetoableChangeListener( | ||
| 196 | String propertyName, | ||
| 197 | VetoableChangeListener listener) { | ||
| 198 | if (listener == null || propertyName == null) { | ||
| 199 | return; | ||
| 200 | } | ||
| 201 | listener = this.map.extract(listener); | ||
| 202 | if (listener != null) { | ||
| 203 | this.map.add(propertyName, listener); | ||
| 204 | } | ||
| 205 | } | ||
| 206 | |||
| 207 | /** | ||
| 208 | * Remove a VetoableChangeListener for a specific property. | ||
| 209 | * If <code>listener</code> was added more than once to the same event | ||
| 210 | * source for the specified property, it will be notified one less time | ||
| 211 | * after being removed. | ||
| 212 | * If <code>propertyName</code> is null, no exception is thrown and no | ||
| 213 | * action is taken. | ||
| 214 | * If <code>listener</code> is null, or was never added for the specified | ||
| 215 | * property, no exception is thrown and no action is taken. | ||
| 216 | * | ||
| 217 | * @param propertyName The name of the property that was listened on. | ||
| 218 | * @param listener The VetoableChangeListener to be removed | ||
| 219 | */ | ||
| 220 | public void removeVetoableChangeListener( | ||
| 221 | String propertyName, | ||
| 222 | VetoableChangeListener listener) { | ||
| 223 | if (listener == null || propertyName == null) { | ||
| 224 | return; | ||
| 225 | } | ||
| 226 | listener = this.map.extract(listener); | ||
| 227 | if (listener != null) { | ||
| 228 | this.map.remove(propertyName, listener); | ||
| 229 | } | ||
| 230 | } | ||
| 231 | |||
| 232 | /** | ||
| 233 | * Returns an array of all the listeners which have been associated | ||
| 234 | * with the named property. | ||
| 235 | * | ||
| 236 | * @param propertyName The name of the property being listened to | ||
| 237 | * @return all the <code>VetoableChangeListeners</code> associated with | ||
| 238 | * the named property. If no such listeners have been added, | ||
| 239 | * or if <code>propertyName</code> is null, an empty array is | ||
| 240 | * returned. | ||
| 241 | * @since 1.4 | ||
| 242 | */ | ||
| 243 | public VetoableChangeListener[] getVetoableChangeListeners(String propertyName) { | ||
| 244 | return this.map.getListeners(propertyName); | ||
| 245 | } | ||
| 246 | |||
| 247 | /** | ||
| 248 | * Reports a constrained property update to listeners | ||
| 249 | * that have been registered to track updates of | ||
| 250 | * all properties or a property with the specified name. | ||
| 251 | * <p> | ||
| 252 | * Any listener can throw a {@code PropertyVetoException} to veto the update. | ||
| 253 | * If one of the listeners vetoes the update, this method passes | ||
| 254 | * a new "undo" {@code PropertyChangeEvent} that reverts to the old value | ||
| 255 | * to all listeners that already confirmed this update | ||
| 256 | * and throws the {@code PropertyVetoException} again. | ||
| 257 | * <p> | ||
| 258 | * No event is fired if old and new values are equal and non-null. | ||
| 259 | * <p> | ||
| 260 | * This is merely a convenience wrapper around the more general | ||
| 261 | * {@link #fireVetoableChange(PropertyChangeEvent)} method. | ||
| 262 | * | ||
| 263 | * @param propertyName the programmatic name of the property that is about to change | ||
| 264 | * @param oldValue the old value of the property | ||
| 265 | * @param newValue the new value of the property | ||
| 266 | * @throws PropertyVetoException if one of listeners vetoes the property update | ||
| 267 | */ | ||
| 268 | public void fireVetoableChange(String propertyName, Object oldValue, Object newValue) | ||
| 269 | throws PropertyVetoException { | ||
| 270 | if (oldValue == null || newValue == null || !oldValue.equals(newValue)) { | ||
| 271 | fireVetoableChange(new PropertyChangeEvent(this.source, propertyName, oldValue, newValue)); | ||
| 272 | } | ||
| 273 | } | ||
| 274 | |||
| 275 | /** | ||
| 276 | * Reports an integer constrained property update to listeners | ||
| 277 | * that have been registered to track updates of | ||
| 278 | * all properties or a property with the specified name. | ||
| 279 | * <p> | ||
| 280 | * Any listener can throw a {@code PropertyVetoException} to veto the update. | ||
| 281 | * If one of the listeners vetoes the update, this method passes | ||
| 282 | * a new "undo" {@code PropertyChangeEvent} that reverts to the old value | ||
| 283 | * to all listeners that already confirmed this update | ||
| 284 | * and throws the {@code PropertyVetoException} again. | ||
| 285 | * <p> | ||
| 286 | * No event is fired if old and new values are equal. | ||
| 287 | * <p> | ||
| 288 | * This is merely a convenience wrapper around the more general | ||
| 289 | * {@link #fireVetoableChange(String, Object, Object)} method. | ||
| 290 | * | ||
| 291 | * @param propertyName the programmatic name of the property that is about to change | ||
| 292 | * @param oldValue the old value of the property | ||
| 293 | * @param newValue the new value of the property | ||
| 294 | * @throws PropertyVetoException if one of listeners vetoes the property update | ||
| 295 | */ | ||
| 296 | public void fireVetoableChange(String propertyName, int oldValue, int newValue) | ||
| 297 | throws PropertyVetoException { | ||
| 298 | if (oldValue != newValue) { | ||
| 299 | fireVetoableChange(propertyName, Integer.valueOf(oldValue), Integer.valueOf(newValue)); | ||
| 300 | } | ||
| 301 | } | ||
| 302 | |||
| 303 | /** | ||
| 304 | * Reports a boolean constrained property update to listeners | ||
| 305 | * that have been registered to track updates of | ||
| 306 | * all properties or a property with the specified name. | ||
| 307 | * <p> | ||
| 308 | * Any listener can throw a {@code PropertyVetoException} to veto the update. | ||
| 309 | * If one of the listeners vetoes the update, this method passes | ||
| 310 | * a new "undo" {@code PropertyChangeEvent} that reverts to the old value | ||
| 311 | * to all listeners that already confirmed this update | ||
| 312 | * and throws the {@code PropertyVetoException} again. | ||
| 313 | * <p> | ||
| 314 | * No event is fired if old and new values are equal. | ||
| 315 | * <p> | ||
| 316 | * This is merely a convenience wrapper around the more general | ||
| 317 | * {@link #fireVetoableChange(String, Object, Object)} method. | ||
| 318 | * | ||
| 319 | * @param propertyName the programmatic name of the property that is about to change | ||
| 320 | * @param oldValue the old value of the property | ||
| 321 | * @param newValue the new value of the property | ||
| 322 | * @throws PropertyVetoException if one of listeners vetoes the property update | ||
| 323 | */ | ||
| 324 | public void fireVetoableChange(String propertyName, boolean oldValue, boolean newValue) | ||
| 325 | throws PropertyVetoException { | ||
| 326 | if (oldValue != newValue) { | ||
| 327 | fireVetoableChange(propertyName, Boolean.valueOf(oldValue), Boolean.valueOf(newValue)); | ||
| 328 | } | ||
| 329 | } | ||
| 330 | |||
| 331 | /** | ||
| 332 | * Fires a property change event to listeners | ||
| 333 | * that have been registered to track updates of | ||
| 334 | * all properties or a property with the specified name. | ||
| 335 | * <p> | ||
| 336 | * Any listener can throw a {@code PropertyVetoException} to veto the update. | ||
| 337 | * If one of the listeners vetoes the update, this method passes | ||
| 338 | * a new "undo" {@code PropertyChangeEvent} that reverts to the old value | ||
| 339 | * to all listeners that already confirmed this update | ||
| 340 | * and throws the {@code PropertyVetoException} again. | ||
| 341 | * <p> | ||
| 342 | * No event is fired if the given event's old and new values are equal and non-null. | ||
| 343 | * | ||
| 344 | * @param event the {@code PropertyChangeEvent} to be fired | ||
| 345 | * @throws PropertyVetoException if one of listeners vetoes the property update | ||
| 346 | */ | ||
| 347 | public void fireVetoableChange(PropertyChangeEvent event) | ||
| 348 | throws PropertyVetoException { | ||
| 349 | Object oldValue = event.getOldValue(); | ||
| 350 | Object newValue = event.getNewValue(); | ||
| 351 | if (oldValue == null || newValue == null || !oldValue.equals(newValue)) { | ||
| 352 | String name = event.getPropertyName(); | ||
| 353 | |||
| 354 | VetoableChangeListener[] common = this.map.get(null); | ||
| 355 | VetoableChangeListener[] named = (name != null) | ||
| 356 | ? this.map.get(name) | ||
| 357 | : null; | ||
| 358 | |||
| 359 | VetoableChangeListener[] listeners; | ||
| 360 | if (common == null) { | ||
| 361 | listeners = named; | ||
| 362 | } | ||
| 363 | else if (named == null) { | ||
| 364 | listeners = common; | ||
| 365 | } | ||
| 366 | else { | ||
| 367 | listeners = new VetoableChangeListener[common.length + named.length]; | ||
| 368 | System.arraycopy(common, 0, listeners, 0, common.length); | ||
| 369 | System.arraycopy(named, 0, listeners, common.length, named.length); | ||
| 370 | } | ||
| 371 | if (listeners != null) { | ||
| 372 | int current = 0; | ||
| 373 | try { | ||
| 374 | while (current < listeners.length) { | ||
| 375 | listeners[current].vetoableChange(event); | ||
| 376 | current++; | ||
| 377 | } | ||
| 378 | } | ||
| 379 | catch (PropertyVetoException veto) { | ||
| 380 | event = new PropertyChangeEvent(this.source, name, newValue, oldValue); | ||
| 381 | for (int i = 0; i < current; i++) { | ||
| 382 | try { | ||
| 383 | listeners[i].vetoableChange(event); | ||
| 384 | } | ||
| 385 | catch (PropertyVetoException exception) { | ||
| 386 | // ignore exceptions that occur during rolling back | ||
| 387 | } | ||
| 388 | } | ||
| 389 | throw veto; // rethrow the veto exception | ||
| 390 | } | ||
| 391 | } | ||
| 392 | } | ||
| 393 | } | ||
| 394 | |||
| 395 | /** | ||
| 396 | * Check if there are any listeners for a specific property, including | ||
| 397 | * those registered on all properties. If <code>propertyName</code> | ||
| 398 | * is null, only check for listeners registered on all properties. | ||
| 399 | * | ||
| 400 | * @param propertyName the property name. | ||
| 401 | * @return true if there are one or more listeners for the given property | ||
| 402 | */ | ||
| 403 | public boolean hasListeners(String propertyName) { | ||
| 404 | return this.map.hasListeners(propertyName); | ||
| 405 | } | ||
| 406 | |||
| 407 | /** | ||
| 408 | * @serialData Null terminated list of <code>VetoableChangeListeners</code>. | ||
| 409 | * <p> | ||
| 410 | * At serialization time we skip non-serializable listeners and | ||
| 411 | * only serialize the serializable listeners. | ||
| 412 | */ | ||
| 413 | private void writeObject(ObjectOutputStream s) throws IOException { | ||
| 414 | Hashtable<String, VetoableChangeSupport> children = null; | ||
| 415 | VetoableChangeListener[] listeners = null; | ||
| 416 | synchronized (this.map) { | ||
| 417 | for (Entry<String, VetoableChangeListener[]> entry : this.map.getEntries()) { | ||
| 418 | String property = entry.getKey(); | ||
| 419 | if (property == null) { | ||
| 420 | listeners = entry.getValue(); | ||
| 421 | } else { | ||
| 422 | if (children == null) { | ||
| 423 | children = new Hashtable<String, VetoableChangeSupport>(); | ||
| 424 | } | ||
| 425 | VetoableChangeSupport vcs = new VetoableChangeSupport(this.source); | ||
| 426 | vcs.map.set(null, entry.getValue()); | ||
| 427 | children.put(property, vcs); | ||
| 428 | } | ||
| 429 | } | ||
| 430 | } | ||
| 431 | ObjectOutputStream.PutField fields = s.putFields(); | ||
| 432 | fields.put("children", children); | ||
| 433 | fields.put("source", this.source); | ||
| 434 | fields.put("vetoableChangeSupportSerializedDataVersion", 2); | ||
| 435 | s.writeFields(); | ||
| 436 | |||
| 437 | if (listeners != null) { | ||
| 438 | for (VetoableChangeListener l : listeners) { | ||
| 439 | if (l instanceof Serializable) { | ||
| 440 | s.writeObject(l); | ||
| 441 | } | ||
| 442 | } | ||
| 443 | } | ||
| 444 | s.writeObject(null); | ||
| 445 | } | ||
| 446 | |||
| 447 | private void readObject(ObjectInputStream s) throws ClassNotFoundException, IOException { | ||
| 448 | this.map = new VetoableChangeListenerMap(); | ||
| 449 | |||
| 450 | ObjectInputStream.GetField fields = s.readFields(); | ||
| 451 | |||
| 452 | Hashtable<String, VetoableChangeSupport> children = (Hashtable<String, VetoableChangeSupport>) fields.get("children", null); | ||
| 453 | this.source = fields.get("source", null); | ||
| 454 | fields.get("vetoableChangeSupportSerializedDataVersion", 2); | ||
| 455 | |||
| 456 | Object listenerOrNull; | ||
| 457 | while (null != (listenerOrNull = s.readObject())) { | ||
| 458 | this.map.add(null, (VetoableChangeListener)listenerOrNull); | ||
| 459 | } | ||
| 460 | if (children != null) { | ||
| 461 | for (Entry<String, VetoableChangeSupport> entry : children.entrySet()) { | ||
| 462 | for (VetoableChangeListener listener : entry.getValue().getVetoableChangeListeners()) { | ||
| 463 | this.map.add(entry.getKey(), listener); | ||
| 464 | } | ||
| 465 | } | ||
| 466 | } | ||
| 467 | } | ||
| 468 | |||
| 469 | /** | ||
| 470 | * The object to be provided as the "source" for any generated events. | ||
| 471 | */ | ||
| 472 | private Object source; | ||
| 473 | |||
| 474 | /** | ||
| 475 | * @serialField children Hashtable | ||
| 476 | * @serialField source Object | ||
| 477 | * @serialField vetoableChangeSupportSerializedDataVersion int | ||
| 478 | */ | ||
| 479 | private static final ObjectStreamField[] serialPersistentFields = { | ||
| 480 | new ObjectStreamField("children", Hashtable.class), | ||
| 481 | new ObjectStreamField("source", Object.class), | ||
| 482 | new ObjectStreamField("vetoableChangeSupportSerializedDataVersion", Integer.TYPE) | ||
| 483 | }; | ||
| 484 | |||
| 485 | /** | ||
| 486 | * Serialization version ID, so we're compatible with JDK 1.1 | ||
| 487 | */ | ||
| 488 | static final long serialVersionUID = -5090210921595982017L; | ||
| 489 | |||
| 490 | /** | ||
| 491 | * This is a {@link ChangeListenerMap ChangeListenerMap} implementation | ||
| 492 | * that works with {@link VetoableChangeListener VetoableChangeListener} objects. | ||
| 493 | */ | ||
| 494 | private static final class VetoableChangeListenerMap extends ChangeListenerMap<VetoableChangeListener> { | ||
| 495 | private static final VetoableChangeListener[] EMPTY = {}; | ||
| 496 | |||
| 497 | /** | ||
| 498 | * Creates an array of {@link VetoableChangeListener VetoableChangeListener} objects. | ||
| 499 | * This method uses the same instance of the empty array | ||
| 500 | * when {@code length} equals {@code 0}. | ||
| 501 | * | ||
| 502 | * @param length the array length | ||
| 503 | * @return an array with specified length | ||
| 504 | */ | ||
| 505 | @Override | ||
| 506 | protected VetoableChangeListener[] newArray(int length) { | ||
| 507 | return (0 < length) | ||
| 508 | ? new VetoableChangeListener[length] | ||
| 509 | : EMPTY; | ||
| 510 | } | ||
| 511 | |||
| 512 | /** | ||
| 513 | * Creates a {@link VetoableChangeListenerProxy VetoableChangeListenerProxy} | ||
| 514 | * object for the specified property. | ||
| 515 | * | ||
| 516 | * @param name the name of the property to listen on | ||
| 517 | * @param listener the listener to process events | ||
| 518 | * @return a {@code VetoableChangeListenerProxy} object | ||
| 519 | */ | ||
| 520 | @Override | ||
| 521 | protected VetoableChangeListener newProxy(String name, VetoableChangeListener listener) { | ||
| 522 | return new VetoableChangeListenerProxy(name, listener); | ||
| 523 | } | ||
| 524 | } | ||
| 525 | } | ||