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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 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.util.*; | ||
| 28 | import java.lang.reflect.*; | ||
| 29 | import java.util.Objects; | ||
| 30 | import sun.reflect.misc.*; | ||
| 31 | |||
| 32 | |||
| 33 | /** | ||
| 34 | * The <code>DefaultPersistenceDelegate</code> is a concrete implementation of | ||
| 35 | * the abstract <code>PersistenceDelegate</code> class and | ||
| 36 | * is the delegate used by default for classes about | ||
| 37 | * which no information is available. The <code>DefaultPersistenceDelegate</code> | ||
| 38 | * provides, version resilient, public API-based persistence for | ||
| 39 | * classes that follow the JavaBeans™ conventions without any class specific | ||
| 40 | * configuration. | ||
| 41 | * <p> | ||
| 42 | * The key assumptions are that the class has a nullary constructor | ||
| 43 | * and that its state is accurately represented by matching pairs | ||
| 44 | * of "setter" and "getter" methods in the order they are returned | ||
| 45 | * by the Introspector. | ||
| 46 | * In addition to providing code-free persistence for JavaBeans, | ||
| 47 | * the <code>DefaultPersistenceDelegate</code> provides a convenient means | ||
| 48 | * to effect persistent storage for classes that have a constructor | ||
| 49 | * that, while not nullary, simply requires some property values | ||
| 50 | * as arguments. | ||
| 51 | * | ||
| 52 | * @see #DefaultPersistenceDelegate(String[]) | ||
| 53 | * @see java.beans.Introspector | ||
| 54 | * | ||
| 55 | * @since 1.4 | ||
| 56 | * | ||
| 57 | * @author Philip Milne | ||
| 58 | */ | ||
| 59 | |||
| 60 | public class DefaultPersistenceDelegate extends PersistenceDelegate { | ||
| 61 | private String[] constructor; | ||
| 62 | private Boolean definesEquals; | ||
| 63 | |||
| 64 | /** | ||
| 65 | * Creates a persistence delegate for a class with a nullary constructor. | ||
| 66 | * | ||
| 67 | * @see #DefaultPersistenceDelegate(java.lang.String[]) | ||
| 68 | */ | ||
| 69 | public DefaultPersistenceDelegate() { | ||
| 70 | this(new String[0]); | ||
| 71 | } | ||
| 72 | |||
| 73 | /** | ||
| 74 | * Creates a default persistence delegate for a class with a | ||
| 75 | * constructor whose arguments are the values of the property | ||
| 76 | * names as specified by <code>constructorPropertyNames</code>. | ||
| 77 | * The constructor arguments are created by | ||
| 78 | * evaluating the property names in the order they are supplied. | ||
| 79 | * To use this class to specify a single preferred constructor for use | ||
| 80 | * in the serialization of a particular type, we state the | ||
| 81 | * names of the properties that make up the constructor's | ||
| 82 | * arguments. For example, the <code>Font</code> class which | ||
| 83 | * does not define a nullary constructor can be handled | ||
| 84 | * with the following persistence delegate: | ||
| 85 | * | ||
| 86 | * <pre> | ||
| 87 | * new DefaultPersistenceDelegate(new String[]{"name", "style", "size"}); | ||
| 88 | * </pre> | ||
| 89 | * | ||
| 90 | * @param constructorPropertyNames The property names for the arguments of this constructor. | ||
| 91 | * | ||
| 92 | * @see #instantiate | ||
| 93 | */ | ||
| 94 | public DefaultPersistenceDelegate(String[] constructorPropertyNames) { | ||
| 95 | this.constructor = constructorPropertyNames; | ||
| 96 | } | ||
| 97 | |||
| 98 | private static boolean definesEquals(Class type) { | ||
| 99 | try { | ||
| 100 | return type == type.getMethod("equals", Object.class).getDeclaringClass(); | ||
| 101 | } | ||
| 102 | catch(NoSuchMethodException e) { | ||
| 103 | return false; | ||
| 104 | } | ||
| 105 | } | ||
| 106 | |||
| 107 | private boolean definesEquals(Object instance) { | ||
| 108 | if (definesEquals != null) { | ||
| 109 | return (definesEquals == Boolean.TRUE); | ||
| 110 | } | ||
| 111 | else { | ||
| 112 | boolean result = definesEquals(instance.getClass()); | ||
| 113 | definesEquals = result ? Boolean.TRUE : Boolean.FALSE; | ||
| 114 | return result; | ||
| 115 | } | ||
| 116 | } | ||
| 117 | |||
| 118 | /** | ||
| 119 | * If the number of arguments in the specified constructor is non-zero and | ||
| 120 | * the class of <code>oldInstance</code> explicitly declares an "equals" method | ||
| 121 | * this method returns the value of <code>oldInstance.equals(newInstance)</code>. | ||
| 122 | * Otherwise, this method uses the superclass's definition which returns true if the | ||
| 123 | * classes of the two instances are equal. | ||
| 124 | * | ||
| 125 | * @param oldInstance The instance to be copied. | ||
| 126 | * @param newInstance The instance that is to be modified. | ||
| 127 | * @return True if an equivalent copy of <code>newInstance</code> may be | ||
| 128 | * created by applying a series of mutations to <code>oldInstance</code>. | ||
| 129 | * | ||
| 130 | * @see #DefaultPersistenceDelegate(String[]) | ||
| 131 | */ | ||
| 132 | protected boolean mutatesTo(Object oldInstance, Object newInstance) { | ||
| 133 | // Assume the instance is either mutable or a singleton | ||
| 134 | // if it has a nullary constructor. | ||
| 135 | return (constructor.length == 0) || !definesEquals(oldInstance) ? | ||
| 136 | super.mutatesTo(oldInstance, newInstance) : | ||
| 137 | oldInstance.equals(newInstance); | ||
| 138 | } | ||
| 139 | |||
| 140 | /** | ||
| 141 | * This default implementation of the <code>instantiate</code> method returns | ||
| 142 | * an expression containing the predefined method name "new" which denotes a | ||
| 143 | * call to a constructor with the arguments as specified in | ||
| 144 | * the <code>DefaultPersistenceDelegate</code>'s constructor. | ||
| 145 | * | ||
| 146 | * @param oldInstance The instance to be instantiated. | ||
| 147 | * @param out The code output stream. | ||
| 148 | * @return An expression whose value is <code>oldInstance</code>. | ||
| 149 | * | ||
| 150 | * @throws NullPointerException if {@code out} is {@code null} | ||
| 151 | * | ||
| 152 | * @see #DefaultPersistenceDelegate(String[]) | ||
| 153 | */ | ||
| 154 | protected Expression instantiate(Object oldInstance, Encoder out) { | ||
| 155 | int nArgs = constructor.length; | ||
| 156 | Class type = oldInstance.getClass(); | ||
| 157 | Object[] constructorArgs = new Object[nArgs]; | ||
| 158 | for(int i = 0; i < nArgs; i++) { | ||
| 159 | try { | ||
| 160 | Method method = findMethod(type, this.constructor[i]); | ||
| 161 | constructorArgs[i] = MethodUtil.invoke(method, oldInstance, new Object[0]); | ||
| 162 | } | ||
| 163 | catch (Exception e) { | ||
| 164 | out.getExceptionListener().exceptionThrown(e); | ||
| 165 | } | ||
| 166 | } | ||
| 167 | return new Expression(oldInstance, oldInstance.getClass(), "new", constructorArgs); | ||
| 168 | } | ||
| 169 | |||
| 170 | private Method findMethod(Class type, String property) { | ||
| 171 | if (property == null) { | ||
| 172 | throw new IllegalArgumentException("Property name is null"); | ||
| 173 | } | ||
| 174 | PropertyDescriptor pd = getPropertyDescriptor(type, property); | ||
| 175 | if (pd == null) { | ||
| 176 | throw new IllegalStateException("Could not find property by the name " + property); | ||
| 177 | } | ||
| 178 | Method method = pd.getReadMethod(); | ||
| 179 | if (method == null) { | ||
| 180 | throw new IllegalStateException("Could not find getter for the property " + property); | ||
| 181 | } | ||
| 182 | return method; | ||
| 183 | } | ||
| 184 | |||
| 185 | private void doProperty(Class type, PropertyDescriptor pd, Object oldInstance, Object newInstance, Encoder out) throws Exception { | ||
| 186 | Method getter = pd.getReadMethod(); | ||
| 187 | Method setter = pd.getWriteMethod(); | ||
| 188 | |||
| 189 | if (getter != null && setter != null) { | ||
| 190 | Expression oldGetExp = new Expression(oldInstance, getter.getName(), new Object[]{}); | ||
| 191 | Expression newGetExp = new Expression(newInstance, getter.getName(), new Object[]{}); | ||
| 192 | Object oldValue = oldGetExp.getValue(); | ||
| 193 | Object newValue = newGetExp.getValue(); | ||
| 194 | out.writeExpression(oldGetExp); | ||
| 195 | if (!Objects.equals(newValue, out.get(oldValue))) { | ||
| 196 | // Search for a static constant with this value; | ||
| 197 | Object e = (Object[])pd.getValue("enumerationValues"); | ||
| 198 | if (e instanceof Object[] && Array.getLength(e) % 3 == 0) { | ||
| 199 | Object[] a = (Object[])e; | ||
| 200 | for(int i = 0; i < a.length; i = i + 3) { | ||
| 201 | try { | ||
| 202 | Field f = type.getField((String)a[i]); | ||
| 203 | if (f.get(null).equals(oldValue)) { | ||
| 204 | out.remove(oldValue); | ||
| 205 | out.writeExpression(new Expression(oldValue, f, "get", new Object[]{null})); | ||
| 206 | } | ||
| 207 | } | ||
| 208 | catch (Exception ex) {} | ||
| 209 | } | ||
| 210 | } | ||
| 211 | invokeStatement(oldInstance, setter.getName(), new Object[]{oldValue}, out); | ||
| 212 | } | ||
| 213 | } | ||
| 214 | } | ||
| 215 | |||
| 216 | static void invokeStatement(Object instance, String methodName, Object[] args, Encoder out) { | ||
| 217 | out.writeStatement(new Statement(instance, methodName, args)); | ||
| 218 | } | ||
| 219 | |||
| 220 | // Write out the properties of this instance. | ||
| 221 | private void initBean(Class type, Object oldInstance, Object newInstance, Encoder out) { | ||
| 222 | for (Field field : type.getFields()) { | ||
| 223 | int mod = field.getModifiers(); | ||
| 224 | if (Modifier.isFinal(mod) || Modifier.isStatic(mod) || Modifier.isTransient(mod)) { | ||
| 225 | continue; | ||
| 226 | } | ||
| 227 | try { | ||
| 228 | Expression oldGetExp = new Expression(field, "get", new Object[] { oldInstance }); | ||
| 229 | Expression newGetExp = new Expression(field, "get", new Object[] { newInstance }); | ||
| 230 | Object oldValue = oldGetExp.getValue(); | ||
| 231 | Object newValue = newGetExp.getValue(); | ||
| 232 | out.writeExpression(oldGetExp); | ||
| 233 | if (!Objects.equals(newValue, out.get(oldValue))) { | ||
| 234 | out.writeStatement(new Statement(field, "set", new Object[] { oldInstance, oldValue })); | ||
| 235 | } | ||
| 236 | } | ||
| 237 | catch (Exception exception) { | ||
| 238 | out.getExceptionListener().exceptionThrown(exception); | ||
| 239 | } | ||
| 240 | } | ||
| 241 | BeanInfo info; | ||
| 242 | try { | ||
| 243 | info = Introspector.getBeanInfo(type); | ||
| 244 | } catch (IntrospectionException exception) { | ||
| 245 | return; | ||
| 246 | } | ||
| 247 | // Properties | ||
| 248 | for (PropertyDescriptor d : info.getPropertyDescriptors()) { | ||
| 249 | if (d.isTransient()) { | ||
| 250 | continue; | ||
| 251 | } | ||
| 252 | try { | ||
| 253 | doProperty(type, d, oldInstance, newInstance, out); | ||
| 254 | } | ||
| 255 | catch (Exception e) { | ||
| 256 | out.getExceptionListener().exceptionThrown(e); | ||
| 257 | } | ||
| 258 | } | ||
| 259 | |||
| 260 | // Listeners | ||
| 261 | /* | ||
| 262 | Pending(milne). There is a general problem with the archival of | ||
| 263 | listeners which is unresolved as of 1.4. Many of the methods | ||
| 264 | which install one object inside another (typically "add" methods | ||
| 265 | or setters) automatically install a listener on the "child" object | ||
| 266 | so that its "parent" may respond to changes that are made to it. | ||
| 267 | For example the JTable:setModel() method automatically adds a | ||
| 268 | TableModelListener (the JTable itself in this case) to the supplied | ||
| 269 | table model. | ||
| 270 | |||
| 271 | We do not need to explictly add these listeners to the model in an | ||
| 272 | archive as they will be added automatically by, in the above case, | ||
| 273 | the JTable's "setModel" method. In some cases, we must specifically | ||
| 274 | avoid trying to do this since the listener may be an inner class | ||
| 275 | that cannot be instantiated using public API. | ||
| 276 | |||
| 277 | No general mechanism currently | ||
| 278 | exists for differentiating between these kind of listeners and | ||
| 279 | those which were added explicitly by the user. A mechanism must | ||
| 280 | be created to provide a general means to differentiate these | ||
| 281 | special cases so as to provide reliable persistence of listeners | ||
| 282 | for the general case. | ||
| 283 | */ | ||
| 284 | if (!java.awt.Component.class.isAssignableFrom(type)) { | ||
| 285 | return; // Just handle the listeners of Components for now. | ||
| 286 | } | ||
| 287 | for (EventSetDescriptor d : info.getEventSetDescriptors()) { | ||
| 288 | if (d.isTransient()) { | ||
| 289 | continue; | ||
| 290 | } | ||
| 291 | Class listenerType = d.getListenerType(); | ||
| 292 | |||
| 293 | |||
| 294 | // The ComponentListener is added automatically, when | ||
| 295 | // Contatiner:add is called on the parent. | ||
| 296 | if (listenerType == java.awt.event.ComponentListener.class) { | ||
| 297 | continue; | ||
| 298 | } | ||
| 299 | |||
| 300 | // JMenuItems have a change listener added to them in | ||
| 301 | // their "add" methods to enable accessibility support - | ||
| 302 | // see the add method in JMenuItem for details. We cannot | ||
| 303 | // instantiate this instance as it is a private inner class | ||
| 304 | // and do not need to do this anyway since it will be created | ||
| 305 | // and installed by the "add" method. Special case this for now, | ||
| 306 | // ignoring all change listeners on JMenuItems. | ||
| 307 | if (listenerType == javax.swing.event.ChangeListener.class && | ||
| 308 | type == javax.swing.JMenuItem.class) { | ||
| 309 | continue; | ||
| 310 | } | ||
| 311 | |||
| 312 | EventListener[] oldL = new EventListener[0]; | ||
| 313 | EventListener[] newL = new EventListener[0]; | ||
| 314 | try { | ||
| 315 | Method m = d.getGetListenerMethod(); | ||
| 316 | oldL = (EventListener[])MethodUtil.invoke(m, oldInstance, new Object[]{}); | ||
| 317 | newL = (EventListener[])MethodUtil.invoke(m, newInstance, new Object[]{}); | ||
| 318 | } | ||
| 319 | catch (Exception e2) { | ||
| 320 | try { | ||
| 321 | Method m = type.getMethod("getListeners", new Class[]{Class.class}); | ||
| 322 | oldL = (EventListener[])MethodUtil.invoke(m, oldInstance, new Object[]{listenerType}); | ||
| 323 | newL = (EventListener[])MethodUtil.invoke(m, newInstance, new Object[]{listenerType}); | ||
| 324 | } | ||
| 325 | catch (Exception e3) { | ||
| 326 | return; | ||
| 327 | } | ||
| 328 | } | ||
| 329 | |||
| 330 | // Asssume the listeners are in the same order and that there are no gaps. | ||
| 331 | // Eventually, this may need to do true differencing. | ||
| 332 | String addListenerMethodName = d.getAddListenerMethod().getName(); | ||
| 333 | for (int i = newL.length; i < oldL.length; i++) { | ||
| 334 | // System.out.println("Adding listener: " + addListenerMethodName + oldL[i]); | ||
| 335 | invokeStatement(oldInstance, addListenerMethodName, new Object[]{oldL[i]}, out); | ||
| 336 | } | ||
| 337 | |||
| 338 | String removeListenerMethodName = d.getRemoveListenerMethod().getName(); | ||
| 339 | for (int i = oldL.length; i < newL.length; i++) { | ||
| 340 | invokeStatement(oldInstance, removeListenerMethodName, new Object[]{newL[i]}, out); | ||
| 341 | } | ||
| 342 | } | ||
| 343 | } | ||
| 344 | |||
| 345 | /** | ||
| 346 | * This default implementation of the <code>initialize</code> method assumes | ||
| 347 | * all state held in objects of this type is exposed via the | ||
| 348 | * matching pairs of "setter" and "getter" methods in the order | ||
| 349 | * they are returned by the Introspector. If a property descriptor | ||
| 350 | * defines a "transient" attribute with a value equal to | ||
| 351 | * <code>Boolean.TRUE</code> the property is ignored by this | ||
| 352 | * default implementation. Note that this use of the word | ||
| 353 | * "transient" is quite independent of the field modifier | ||
| 354 | * that is used by the <code>ObjectOutputStream</code>. | ||
| 355 | * <p> | ||
| 356 | * For each non-transient property, an expression is created | ||
| 357 | * in which the nullary "getter" method is applied | ||
| 358 | * to the <code>oldInstance</code>. The value of this | ||
| 359 | * expression is the value of the property in the instance that is | ||
| 360 | * being serialized. If the value of this expression | ||
| 361 | * in the cloned environment <code>mutatesTo</code> the | ||
| 362 | * target value, the new value is initialized to make it | ||
| 363 | * equivalent to the old value. In this case, because | ||
| 364 | * the property value has not changed there is no need to | ||
| 365 | * call the corresponding "setter" method and no statement | ||
| 366 | * is emitted. If not however, the expression for this value | ||
| 367 | * is replaced with another expression (normally a constructor) | ||
| 368 | * and the corresponding "setter" method is called to install | ||
| 369 | * the new property value in the object. This scheme removes | ||
| 370 | * default information from the output produced by streams | ||
| 371 | * using this delegate. | ||
| 372 | * <p> | ||
| 373 | * In passing these statements to the output stream, where they | ||
| 374 | * will be executed, side effects are made to the <code>newInstance</code>. | ||
| 375 | * In most cases this allows the problem of properties | ||
| 376 | * whose values depend on each other to actually help the | ||
| 377 | * serialization process by making the number of statements | ||
| 378 | * that need to be written to the output smaller. In general, | ||
| 379 | * the problem of handling interdependent properties is reduced to | ||
| 380 | * that of finding an order for the properties in | ||
| 381 | * a class such that no property value depends on the value of | ||
| 382 | * a subsequent property. | ||
| 383 | * | ||
| 384 | * @param oldInstance The instance to be copied. | ||
| 385 | * @param newInstance The instance that is to be modified. | ||
| 386 | * @param out The stream to which any initialization statements should be written. | ||
| 387 | * | ||
| 388 | * @throws NullPointerException if {@code out} is {@code null} | ||
| 389 | * | ||
| 390 | * @see java.beans.Introspector#getBeanInfo | ||
| 391 | * @see java.beans.PropertyDescriptor | ||
| 392 | */ | ||
| 393 | protected void initialize(Class<?> type, | ||
| 394 | Object oldInstance, Object newInstance, | ||
| 395 | Encoder out) | ||
| 396 | { | ||
| 397 | // System.out.println("DefulatPD:initialize" + type); | ||
| 398 | super.initialize(type, oldInstance, newInstance, out); | ||
| 399 | if (oldInstance.getClass() == type) { // !type.isInterface()) { | ||
| 400 | initBean(type, oldInstance, newInstance, out); | ||
| 401 | } | ||
| 402 | } | ||
| 403 | |||
| 404 | private static PropertyDescriptor getPropertyDescriptor(Class type, String property) { | ||
| 405 | try { | ||
| 406 | for (PropertyDescriptor pd : Introspector.getBeanInfo(type).getPropertyDescriptors()) { | ||
| 407 | if (property.equals(pd.getName())) | ||
| 408 | return pd; | ||
| 409 | } | ||
| 410 | } catch (IntrospectionException exception) { | ||
| 411 | } | ||
| 412 | return null; | ||
| 413 | } | ||
| 414 | } | ||