Showing the changes to java/pkg/java/beans/beancontext/BeanContextChildSupport.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,373 @@ | |||
| 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 | } | ||