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| 1 | +/* | |
| 2 | + * Copyright (c) 1998, 2004, 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 java.beans.beancontext; | |
| 27 | + | |
| 28 | +import java.beans.PropertyChangeEvent; | |
| 29 | +import java.beans.PropertyChangeListener; | |
| 30 | +import java.beans.PropertyChangeSupport; | |
| 31 | + | |
| 32 | +import java.beans.VetoableChangeListener; | |
| 33 | +import java.beans.VetoableChangeSupport; | |
| 34 | + | |
| 35 | +import java.beans.PropertyVetoException; | |
| 36 | + | |
| 37 | +import java.io.IOException; | |
| 38 | +import java.io.ObjectInputStream; | |
| 39 | +import java.io.ObjectOutputStream; | |
| 40 | +import java.io.Serializable; | |
| 41 | + | |
| 42 | +/** | |
| 43 | + * <p> | |
| 44 | + * This is a general support class to provide support for implementing the | |
| 45 | + * BeanContextChild protocol. | |
| 46 | + * | |
| 47 | + * This class may either be directly subclassed, or encapsulated and delegated | |
| 48 | + * to in order to implement this interface for a given component. | |
| 49 | + * </p> | |
| 50 | + * | |
| 51 | + * @author Laurence P. G. Cable | |
| 52 | + * @since 1.2 | |
| 53 | + * | |
| 54 | + * @see java.beans.beancontext.BeanContext | |
| 55 | + * @see java.beans.beancontext.BeanContextServices | |
| 56 | + * @see java.beans.beancontext.BeanContextChild | |
| 57 | + */ | |
| 58 | + | |
| 59 | +public class BeanContextChildSupport implements BeanContextChild, BeanContextServicesListener, Serializable { | |
| 60 | + | |
| 61 | + static final long serialVersionUID = 6328947014421475877L; | |
| 62 | + | |
| 63 | + /** | |
| 64 | + * construct a BeanContextChildSupport where this class has been | |
| 65 | + * subclassed in order to implement the JavaBean component itself. | |
| 66 | + */ | |
| 67 | + | |
| 68 | + public BeanContextChildSupport() { | |
| 69 | + super(); | |
| 70 | + | |
| 71 | + beanContextChildPeer = this; | |
| 72 | + | |
| 73 | + pcSupport = new PropertyChangeSupport(beanContextChildPeer); | |
| 74 | + vcSupport = new VetoableChangeSupport(beanContextChildPeer); | |
| 75 | + } | |
| 76 | + | |
| 77 | + /** | |
| 78 | + * construct a BeanContextChildSupport where the JavaBean component | |
| 79 | + * itself implements BeanContextChild, and encapsulates this, delegating | |
| 80 | + * that interface to this implementation | |
| 81 | + */ | |
| 82 | + | |
| 83 | + public BeanContextChildSupport(BeanContextChild bcc) { | |
| 84 | + super(); | |
| 85 | + | |
| 86 | + beanContextChildPeer = (bcc != null) ? bcc : this; | |
| 87 | + | |
| 88 | + pcSupport = new PropertyChangeSupport(beanContextChildPeer); | |
| 89 | + vcSupport = new VetoableChangeSupport(beanContextChildPeer); | |
| 90 | + } | |
| 91 | + | |
| 92 | + /** | |
| 93 | + * Sets the <code>BeanContext</code> for | |
| 94 | + * this <code>BeanContextChildSupport</code>. | |
| 95 | + * @param bc the new value to be assigned to the <code>BeanContext</code> | |
| 96 | + * property | |
| 97 | + * @throws <code>PropertyVetoException</code> if the change is rejected | |
| 98 | + */ | |
| 99 | + public synchronized void setBeanContext(BeanContext bc) throws PropertyVetoException { | |
| 100 | + if (bc == beanContext) return; | |
| 101 | + | |
| 102 | + BeanContext oldValue = beanContext; | |
| 103 | + BeanContext newValue = bc; | |
| 104 | + | |
| 105 | + if (!rejectedSetBCOnce) { | |
| 106 | + if (rejectedSetBCOnce = !validatePendingSetBeanContext(bc)) { | |
| 107 | + throw new PropertyVetoException( | |
| 108 | + "setBeanContext() change rejected:", | |
| 109 | + new PropertyChangeEvent(beanContextChildPeer, "beanContext", oldValue, newValue) | |
| 110 | + ); | |
| 111 | + } | |
| 112 | + | |
| 113 | + try { | |
| 114 | + fireVetoableChange("beanContext", | |
| 115 | + oldValue, | |
| 116 | + newValue | |
| 117 | + ); | |
| 118 | + } catch (PropertyVetoException pve) { | |
| 119 | + rejectedSetBCOnce = true; | |
| 120 | + | |
| 121 | + throw pve; // re-throw | |
| 122 | + } | |
| 123 | + } | |
| 124 | + | |
| 125 | + if (beanContext != null) releaseBeanContextResources(); | |
| 126 | + | |
| 127 | + beanContext = newValue; | |
| 128 | + rejectedSetBCOnce = false; | |
| 129 | + | |
| 130 | + firePropertyChange("beanContext", | |
| 131 | + oldValue, | |
| 132 | + newValue | |
| 133 | + ); | |
| 134 | + | |
| 135 | + if (beanContext != null) initializeBeanContextResources(); | |
| 136 | + } | |
| 137 | + | |
| 138 | + /** | |
| 139 | + * Gets the nesting <code>BeanContext</code> | |
| 140 | + * for this <code>BeanContextChildSupport</code>. | |
| 141 | + * @return the nesting <code>BeanContext</code> for | |
| 142 | + * this <code>BeanContextChildSupport</code>. | |
| 143 | + */ | |
| 144 | + public synchronized BeanContext getBeanContext() { return beanContext; } | |
| 145 | + | |
| 146 | + /** | |
| 147 | + * Add a PropertyChangeListener for a specific property. | |
| 148 | + * The same listener object may be added more than once. For each | |
| 149 | + * property, the listener will be invoked the number of times it was added | |
| 150 | + * for that property. | |
| 151 | + * If <code>name</code> or <code>pcl</code> is null, no exception is thrown | |
| 152 | + * and no action is taken. | |
| 153 | + * | |
| 154 | + * @param name The name of the property to listen on | |
| 155 | + * @param pcl The <code>PropertyChangeListener</code> to be added | |
| 156 | + */ | |
| 157 | + public void addPropertyChangeListener(String name, PropertyChangeListener pcl) { | |
| 158 | + pcSupport.addPropertyChangeListener(name, pcl); | |
| 159 | + } | |
| 160 | + | |
| 161 | + /** | |
| 162 | + * Remove a PropertyChangeListener for a specific property. | |
| 163 | + * If <code>pcl</code> was added more than once to the same event | |
| 164 | + * source for the specified property, it will be notified one less time | |
| 165 | + * after being removed. | |
| 166 | + * If <code>name</code> is null, no exception is thrown | |
| 167 | + * and no action is taken. | |
| 168 | + * If <code>pcl</code> is null, or was never added for the specified | |
| 169 | + * property, no exception is thrown and no action is taken. | |
| 170 | + * | |
| 171 | + * @param name The name of the property that was listened on | |
| 172 | + * @param pcl The PropertyChangeListener to be removed | |
| 173 | + */ | |
| 174 | + public void removePropertyChangeListener(String name, PropertyChangeListener pcl) { | |
| 175 | + pcSupport.removePropertyChangeListener(name, pcl); | |
| 176 | + } | |
| 177 | + | |
| 178 | + /** | |
| 179 | + * Add a VetoableChangeListener for a specific property. | |
| 180 | + * The same listener object may be added more than once. For each | |
| 181 | + * property, the listener will be invoked the number of times it was added | |
| 182 | + * for that property. | |
| 183 | + * If <code>name</code> or <code>vcl</code> is null, no exception is thrown | |
| 184 | + * and no action is taken. | |
| 185 | + * | |
| 186 | + * @param name The name of the property to listen on | |
| 187 | + * @param vcl The <code>VetoableChangeListener</code> to be added | |
| 188 | + */ | |
| 189 | + public void addVetoableChangeListener(String name, VetoableChangeListener vcl) { | |
| 190 | + vcSupport.addVetoableChangeListener(name, vcl); | |
| 191 | + } | |
| 192 | + | |
| 193 | + /** | |
| 194 | + * Removes a <code>VetoableChangeListener</code>. | |
| 195 | + * If <code>pcl</code> was added more than once to the same event | |
| 196 | + * source for the specified property, it will be notified one less time | |
| 197 | + * after being removed. | |
| 198 | + * If <code>name</code> is null, no exception is thrown | |
| 199 | + * and no action is taken. | |
| 200 | + * If <code>vcl</code> is null, or was never added for the specified | |
| 201 | + * property, no exception is thrown and no action is taken. | |
| 202 | + * | |
| 203 | + * @param name The name of the property that was listened on | |
| 204 | + * @param vcl The <code>VetoableChangeListener</code> to be removed | |
| 205 | + */ | |
| 206 | + public void removeVetoableChangeListener(String name, VetoableChangeListener vcl) { | |
| 207 | + vcSupport.removeVetoableChangeListener(name, vcl); | |
| 208 | + } | |
| 209 | + | |
| 210 | + /** | |
| 211 | + * A service provided by the nesting BeanContext has been revoked. | |
| 212 | + * | |
| 213 | + * Subclasses may override this method in order to implement their own | |
| 214 | + * behaviors. | |
| 215 | + * @param bcsre The <code>BeanContextServiceRevokedEvent</code> fired as a | |
| 216 | + * result of a service being revoked | |
| 217 | + */ | |
| 218 | + public void serviceRevoked(BeanContextServiceRevokedEvent bcsre) { } | |
| 219 | + | |
| 220 | + /** | |
| 221 | + * A new service is available from the nesting BeanContext. | |
| 222 | + * | |
| 223 | + * Subclasses may override this method in order to implement their own | |
| 224 | + * behaviors | |
| 225 | + * @param bcsae The BeanContextServiceAvailableEvent fired as a | |
| 226 | + * result of a service becoming available | |
| 227 | + * | |
| 228 | + */ | |
| 229 | + public void serviceAvailable(BeanContextServiceAvailableEvent bcsae) { } | |
| 230 | + | |
| 231 | + /** | |
| 232 | + * Gets the <tt>BeanContextChild</tt> associated with this | |
| 233 | + * <tt>BeanContextChildSupport</tt>. | |
| 234 | + * | |
| 235 | + * @return the <tt>BeanContextChild</tt> peer of this class | |
| 236 | + */ | |
| 237 | + public BeanContextChild getBeanContextChildPeer() { return beanContextChildPeer; } | |
| 238 | + | |
| 239 | + /** | |
| 240 | + * Reports whether or not this class is a delegate of another. | |
| 241 | + * | |
| 242 | + * @return true if this class is a delegate of another | |
| 243 | + */ | |
| 244 | + public boolean isDelegated() { return !this.equals(beanContextChildPeer); } | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * Report a bound property update to any registered listeners. No event is | |
| 248 | + * fired if old and new are equal and non-null. | |
| 249 | + * @param name The programmatic name of the property that was changed | |
| 250 | + * @param oldValue The old value of the property | |
| 251 | + * @param newValue The new value of the property | |
| 252 | + */ | |
| 253 | + public void firePropertyChange(String name, Object oldValue, Object newValue) { | |
| 254 | + pcSupport.firePropertyChange(name, oldValue, newValue); | |
| 255 | + } | |
| 256 | + | |
| 257 | + /** | |
| 258 | + * Report a vetoable property update to any registered listeners. | |
| 259 | + * If anyone vetos the change, then fire a new event | |
| 260 | + * reverting everyone to the old value and then rethrow | |
| 261 | + * the PropertyVetoException. <P> | |
| 262 | + * | |
| 263 | + * No event is fired if old and new are equal and non-null. | |
| 264 | + * <P> | |
| 265 | + * @param name The programmatic name of the property that is about to | |
| 266 | + * change | |
| 267 | + * | |
| 268 | + * @param oldValue The old value of the property | |
| 269 | + * @param newValue - The new value of the property | |
| 270 | + * | |
| 271 | + * @throws PropertyVetoException if the recipient wishes the property | |
| 272 | + * change to be rolled back. | |
| 273 | + */ | |
| 274 | + public void fireVetoableChange(String name, Object oldValue, Object newValue) throws PropertyVetoException { | |
| 275 | + vcSupport.fireVetoableChange(name, oldValue, newValue); | |
| 276 | + } | |
| 277 | + | |
| 278 | + /** | |
| 279 | + * Called from setBeanContext to validate (or otherwise) the | |
| 280 | + * pending change in the nesting BeanContext property value. | |
| 281 | + * Returning false will cause setBeanContext to throw | |
| 282 | + * PropertyVetoException. | |
| 283 | + * @param newValue the new value that has been requested for | |
| 284 | + * the BeanContext property | |
| 285 | + * @return <code>true</code> if the change operation is to be vetoed | |
| 286 | + */ | |
| 287 | + public boolean validatePendingSetBeanContext(BeanContext newValue) { | |
| 288 | + return true; | |
| 289 | + } | |
| 290 | + | |
| 291 | + /** | |
| 292 | + * This method may be overridden by subclasses to provide their own | |
| 293 | + * release behaviors. When invoked any resources held by this instance | |
| 294 | + * obtained from its current BeanContext property should be released | |
| 295 | + * since the object is no longer nested within that BeanContext. | |
| 296 | + */ | |
| 297 | + | |
| 298 | + protected void releaseBeanContextResources() { | |
| 299 | + // do nothing | |
| 300 | + } | |
| 301 | + | |
| 302 | + /** | |
| 303 | + * This method may be overridden by subclasses to provide their own | |
| 304 | + * initialization behaviors. When invoked any resources requried by the | |
| 305 | + * BeanContextChild should be obtained from the current BeanContext. | |
| 306 | + */ | |
| 307 | + | |
| 308 | + protected void initializeBeanContextResources() { | |
| 309 | + // do nothing | |
| 310 | + } | |
| 311 | + | |
| 312 | + /** | |
| 313 | + * Write the persistence state of the object. | |
| 314 | + */ | |
| 315 | + | |
| 316 | + private void writeObject(ObjectOutputStream oos) throws IOException { | |
| 317 | + | |
| 318 | + /* | |
| 319 | + * dont serialize if we are delegated and the delegator isnt also | |
| 320 | + * serializable. | |
| 321 | + */ | |
| 322 | + | |
| 323 | + if (!equals(beanContextChildPeer) && !(beanContextChildPeer instanceof Serializable)) | |
| 324 | + throw new IOException("BeanContextChildSupport beanContextChildPeer not Serializable"); | |
| 325 | + | |
| 326 | + else | |
| 327 | + oos.defaultWriteObject(); | |
| 328 | + | |
| 329 | + } | |
| 330 | + | |
| 331 | + | |
| 332 | + /** | |
| 333 | + * Restore a persistent object, must wait for subsequent setBeanContext() | |
| 334 | + * to fully restore any resources obtained from the new nesting | |
| 335 | + * BeanContext | |
| 336 | + */ | |
| 337 | + | |
| 338 | + private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException { | |
| 339 | + ois.defaultReadObject(); | |
| 340 | + } | |
| 341 | + | |
| 342 | + /* | |
| 343 | + * fields | |
| 344 | + */ | |
| 345 | + | |
| 346 | + /** | |
| 347 | + * The <code>BeanContext</code> in which | |
| 348 | + * this <code>BeanContextChild</code> is nested. | |
| 349 | + */ | |
| 350 | + public BeanContextChild beanContextChildPeer; | |
| 351 | + | |
| 352 | + /** | |
| 353 | + * The <tt>PropertyChangeSupport</tt> associated with this | |
| 354 | + * <tt>BeanContextChildSupport</tt>. | |
| 355 | + */ | |
| 356 | + protected PropertyChangeSupport pcSupport; | |
| 357 | + | |
| 358 | + /** | |
| 359 | + * The <tt>VetoableChangeSupport</tt> associated with this | |
| 360 | + * <tt>BeanContextChildSupport</tt>. | |
| 361 | + */ | |
| 362 | + protected VetoableChangeSupport vcSupport; | |
| 363 | + | |
| 364 | + protected transient BeanContext beanContext; | |
| 365 | + | |
| 366 | + /** | |
| 367 | + * A flag indicating that there has been | |
| 368 | + * at least one <code>PropertyChangeVetoException</code> | |
| 369 | + * thrown for the attempted setBeanContext operation. | |
| 370 | + */ | |
| 371 | + protected transient boolean rejectedSetBCOnce; | |
| 372 | + | |
| 373 | +} | |