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| 1 | /* | ||
| 2 | * Copyright (c) 1996, 2003, 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.rmi.server; | ||
| 27 | |||
| 28 | import java.rmi.Remote; | ||
| 29 | import java.rmi.NoSuchObjectException; | ||
| 30 | import java.lang.reflect.Proxy; | ||
| 31 | import sun.rmi.server.Util; | ||
| 32 | |||
| 33 | /** | ||
| 34 | * The <code>RemoteObject</code> class implements the | ||
| 35 | * <code>java.lang.Object</code> behavior for remote objects. | ||
| 36 | * <code>RemoteObject</code> provides the remote semantics of Object by | ||
| 37 | * implementing methods for hashCode, equals, and toString. | ||
| 38 | * | ||
| 39 | * @author Ann Wollrath | ||
| 40 | * @author Laird Dornin | ||
| 41 | * @author Peter Jones | ||
| 42 | * @since JDK1.1 | ||
| 43 | */ | ||
| 44 | public abstract class RemoteObject implements Remote, java.io.Serializable { | ||
| 45 | |||
| 46 | /** The object's remote reference. */ | ||
| 47 | transient protected RemoteRef ref; | ||
| 48 | |||
| 49 | /** indicate compatibility with JDK 1.1.x version of class */ | ||
| 50 | private static final long serialVersionUID = -3215090123894869218L; | ||
| 51 | |||
| 52 | /** | ||
| 53 | * Creates a remote object. | ||
| 54 | */ | ||
| 55 | protected RemoteObject() { | ||
| 56 | ref = null; | ||
| 57 | } | ||
| 58 | |||
| 59 | /** | ||
| 60 | * Creates a remote object, initialized with the specified remote | ||
| 61 | * reference. | ||
| 62 | * @param newref remote reference | ||
| 63 | */ | ||
| 64 | protected RemoteObject(RemoteRef newref) { | ||
| 65 | ref = newref; | ||
| 66 | } | ||
| 67 | |||
| 68 | /** | ||
| 69 | * Returns the remote reference for the remote object. | ||
| 70 | * | ||
| 71 | * <p>Note: The object returned from this method may be an instance of | ||
| 72 | * an implementation-specific class. The <code>RemoteObject</code> | ||
| 73 | * class ensures serialization portability of its instances' remote | ||
| 74 | * references through the behavior of its custom | ||
| 75 | * <code>writeObject</code> and <code>readObject</code> methods. An | ||
| 76 | * instance of <code>RemoteRef</code> should not be serialized outside | ||
| 77 | * of its <code>RemoteObject</code> wrapper instance or the result may | ||
| 78 | * be unportable. | ||
| 79 | * | ||
| 80 | * @return remote reference for the remote object | ||
| 81 | * @since 1.2 | ||
| 82 | */ | ||
| 83 | public RemoteRef getRef() { | ||
| 84 | return ref; | ||
| 85 | } | ||
| 86 | |||
| 87 | /** | ||
| 88 | * Returns the stub for the remote object <code>obj</code> passed | ||
| 89 | * as a parameter. This operation is only valid <i>after</i> | ||
| 90 | * the object has been exported. | ||
| 91 | * @param obj the remote object whose stub is needed | ||
| 92 | * @return the stub for the remote object, <code>obj</code>. | ||
| 93 | * @exception NoSuchObjectException if the stub for the | ||
| 94 | * remote object could not be found. | ||
| 95 | * @since 1.2 | ||
| 96 | */ | ||
| 97 | public static Remote toStub(Remote obj) throws NoSuchObjectException { | ||
| 98 | if (obj instanceof RemoteStub || | ||
| 99 | (obj != null && | ||
| 100 | Proxy.isProxyClass(obj.getClass()) && | ||
| 101 | Proxy.getInvocationHandler(obj) instanceof | ||
| 102 | RemoteObjectInvocationHandler)) | ||
| 103 | { | ||
| 104 | return obj; | ||
| 105 | } else { | ||
| 106 | return sun.rmi.transport.ObjectTable.getStub(obj); | ||
| 107 | } | ||
| 108 | } | ||
| 109 | |||
| 110 | /** | ||
| 111 | * Returns a hashcode for a remote object. Two remote object stubs | ||
| 112 | * that refer to the same remote object will have the same hash code | ||
| 113 | * (in order to support remote objects as keys in hash tables). | ||
| 114 | * | ||
| 115 | * @see java.util.Hashtable | ||
| 116 | */ | ||
| 117 | public int hashCode() { | ||
| 118 | return (ref == null) ? super.hashCode() : ref.remoteHashCode(); | ||
| 119 | } | ||
| 120 | |||
| 121 | /** | ||
| 122 | * Compares two remote objects for equality. | ||
| 123 | * Returns a boolean that indicates whether this remote object is | ||
| 124 | * equivalent to the specified Object. This method is used when a | ||
| 125 | * remote object is stored in a hashtable. | ||
| 126 | * If the specified Object is not itself an instance of RemoteObject, | ||
| 127 | * then this method delegates by returning the result of invoking the | ||
| 128 | * <code>equals</code> method of its parameter with this remote object | ||
| 129 | * as the argument. | ||
| 130 | * @param obj the Object to compare with | ||
| 131 | * @return true if these Objects are equal; false otherwise. | ||
| 132 | * @see java.util.Hashtable | ||
| 133 | */ | ||
| 134 | public boolean equals(Object obj) { | ||
| 135 | if (obj instanceof RemoteObject) { | ||
| 136 | if (ref == null) { | ||
| 137 | return obj == this; | ||
| 138 | } else { | ||
| 139 | return ref.remoteEquals(((RemoteObject)obj).ref); | ||
| 140 | } | ||
| 141 | } else if (obj != null) { | ||
| 142 | /* | ||
| 143 | * Fix for 4099660: if object is not an instance of RemoteObject, | ||
| 144 | * use the result of its equals method, to support symmetry is a | ||
| 145 | * remote object implementation class that does not extend | ||
| 146 | * RemoteObject wishes to support equality with its stub objects. | ||
| 147 | */ | ||
| 148 | return obj.equals(this); | ||
| 149 | } else { | ||
| 150 | return false; | ||
| 151 | } | ||
| 152 | } | ||
| 153 | |||
| 154 | /** | ||
| 155 | * Returns a String that represents the value of this remote object. | ||
| 156 | */ | ||
| 157 | public String toString() { | ||
| 158 | String classname = Util.getUnqualifiedName(getClass()); | ||
| 159 | return (ref == null) ? classname : | ||
| 160 | classname + "[" + ref.remoteToString() + "]"; | ||
| 161 | } | ||
| 162 | |||
| 163 | /** | ||
| 164 | * <code>writeObject</code> for custom serialization. | ||
| 165 | * | ||
| 166 | * <p>This method writes this object's serialized form for this class | ||
| 167 | * as follows: | ||
| 168 | * | ||
| 169 | * <p>The {@link RemoteRef#getRefClass(java.io.ObjectOutput) getRefClass} | ||
| 170 | * method is invoked on this object's <code>ref</code> field | ||
| 171 | * to obtain its external ref type name. | ||
| 172 | * If the value returned by <code>getRefClass</code> was | ||
| 173 | * a non-<code>null</code> string of length greater than zero, | ||
| 174 | * the <code>writeUTF</code> method is invoked on <code>out</code> | ||
| 175 | * with the value returned by <code>getRefClass</code>, and then | ||
| 176 | * the <code>writeExternal</code> method is invoked on | ||
| 177 | * this object's <code>ref</code> field passing <code>out</code> | ||
| 178 | * as the argument; otherwise, | ||
| 179 | * the <code>writeUTF</code> method is invoked on <code>out</code> | ||
| 180 | * with a zero-length string (<code>""</code>), and then | ||
| 181 | * the <code>writeObject</code> method is invoked on <code>out</code> | ||
| 182 | * passing this object's <code>ref</code> field as the argument. | ||
| 183 | * | ||
| 184 | * @serialData | ||
| 185 | * | ||
| 186 | * The serialized data for this class comprises a string (written with | ||
| 187 | * <code>ObjectOutput.writeUTF</code>) that is either the external | ||
| 188 | * ref type name of the contained <code>RemoteRef</code> instance | ||
| 189 | * (the <code>ref</code> field) or a zero-length string, followed by | ||
| 190 | * either the external form of the <code>ref</code> field as written by | ||
| 191 | * its <code>writeExternal</code> method if the string was of non-zero | ||
| 192 | * length, or the serialized form of the <code>ref</code> field as | ||
| 193 | * written by passing it to the serialization stream's | ||
| 194 | * <code>writeObject</code> if the string was of zero length. | ||
| 195 | * | ||
| 196 | * <p>If this object is an instance of | ||
| 197 | * {@link RemoteStub} or {@link RemoteObjectInvocationHandler} | ||
| 198 | * that was returned from any of | ||
| 199 | * the <code>UnicastRemoteObject.exportObject</code> methods | ||
| 200 | * and custom socket factories are not used, | ||
| 201 | * the external ref type name is <code>"UnicastRef"</code>. | ||
| 202 | * | ||
| 203 | * If this object is an instance of | ||
| 204 | * <code>RemoteStub</code> or <code>RemoteObjectInvocationHandler</code> | ||
| 205 | * that was returned from any of | ||
| 206 | * the <code>UnicastRemoteObject.exportObject</code> methods | ||
| 207 | * and custom socket factories are used, | ||
| 208 | * the external ref type name is <code>"UnicastRef2"</code>. | ||
| 209 | * | ||
| 210 | * If this object is an instance of | ||
| 211 | * <code>RemoteStub</code> or <code>RemoteObjectInvocationHandler</code> | ||
| 212 | * that was returned from any of | ||
| 213 | * the <code>java.rmi.activation.Activatable.exportObject</code> methods, | ||
| 214 | * the external ref type name is <code>"ActivatableRef"</code>. | ||
| 215 | * | ||
| 216 | * If this object is an instance of | ||
| 217 | * <code>RemoteStub</code> or <code>RemoteObjectInvocationHandler</code> | ||
| 218 | * that was returned from | ||
| 219 | * the <code>RemoteObject.toStub</code> method (and the argument passed | ||
| 220 | * to <code>toStub</code> was not itself a <code>RemoteStub</code>), | ||
| 221 | * the external ref type name is a function of how the remote object | ||
| 222 | * passed to <code>toStub</code> was exported, as described above. | ||
| 223 | * | ||
| 224 | * If this object is an instance of | ||
| 225 | * <code>RemoteStub</code> or <code>RemoteObjectInvocationHandler</code> | ||
| 226 | * that was originally created via deserialization, | ||
| 227 | * the external ref type name is the same as that which was read | ||
| 228 | * when this object was deserialized. | ||
| 229 | * | ||
| 230 | * <p>If this object is an instance of | ||
| 231 | * <code>java.rmi.server.UnicastRemoteObject</code> that does not | ||
| 232 | * use custom socket factories, | ||
| 233 | * the external ref type name is <code>"UnicastServerRef"</code>. | ||
| 234 | * | ||
| 235 | * If this object is an instance of | ||
| 236 | * <code>UnicastRemoteObject</code> that does | ||
| 237 | * use custom socket factories, | ||
| 238 | * the external ref type name is <code>"UnicastServerRef2"</code>. | ||
| 239 | * | ||
| 240 | * <p>Following is the data that must be written by the | ||
| 241 | * <code>writeExternal</code> method and read by the | ||
| 242 | * <code>readExternal</code> method of <code>RemoteRef</code> | ||
| 243 | * implementation classes that correspond to the each of the | ||
| 244 | * defined external ref type names: | ||
| 245 | * | ||
| 246 | * <p>For <code>"UnicastRef"</code>: | ||
| 247 | * | ||
| 248 | * <ul> | ||
| 249 | * | ||
| 250 | * <li>the hostname of the referenced remote object, | ||
| 251 | * written by {@link java.io.ObjectOutput#writeUTF(String)} | ||
| 252 | * | ||
| 253 | * <li>the port of the referenced remote object, | ||
| 254 | * written by {@link java.io.ObjectOutput#writeInt(int)} | ||
| 255 | * | ||
| 256 | * <li>the data written as a result of calling | ||
| 257 | * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)} | ||
| 258 | * on the <code>ObjID</code> instance contained in the reference | ||
| 259 | * | ||
| 260 | * <li>the boolean value <code>false</code>, | ||
| 261 | * written by {@link java.io.ObjectOutput#writeBoolean(boolean)} | ||
| 262 | * | ||
| 263 | * </ul> | ||
| 264 | * | ||
| 265 | * <p>For <code>"UnicastRef2"</code> with a | ||
| 266 | * <code>null</code> client socket factory: | ||
| 267 | * | ||
| 268 | * <ul> | ||
| 269 | * | ||
| 270 | * <li>the byte value <code>0x00</code> | ||
| 271 | * (indicating <code>null</code> client socket factory), | ||
| 272 | * written by {@link java.io.ObjectOutput#writeByte(int)} | ||
| 273 | * | ||
| 274 | * <li>the hostname of the referenced remote object, | ||
| 275 | * written by {@link java.io.ObjectOutput#writeUTF(String)} | ||
| 276 | * | ||
| 277 | * <li>the port of the referenced remote object, | ||
| 278 | * written by {@link java.io.ObjectOutput#writeInt(int)} | ||
| 279 | * | ||
| 280 | * <li>the data written as a result of calling | ||
| 281 | * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)} | ||
| 282 | * on the <code>ObjID</code> instance contained in the reference | ||
| 283 | * | ||
| 284 | * <li>the boolean value <code>false</code>, | ||
| 285 | * written by {@link java.io.ObjectOutput#writeBoolean(boolean)} | ||
| 286 | * | ||
| 287 | * </ul> | ||
| 288 | * | ||
| 289 | * <p>For <code>"UnicastRef2"</code> with a | ||
| 290 | * non-<code>null</code> client socket factory: | ||
| 291 | * | ||
| 292 | * <ul> | ||
| 293 | * | ||
| 294 | * <li>the byte value <code>0x01</code> | ||
| 295 | * (indicating non-<code>null</code> client socket factory), | ||
| 296 | * written by {@link java.io.ObjectOutput#writeByte(int)} | ||
| 297 | * | ||
| 298 | * <li>the hostname of the referenced remote object, | ||
| 299 | * written by {@link java.io.ObjectOutput#writeUTF(String)} | ||
| 300 | * | ||
| 301 | * <li>the port of the referenced remote object, | ||
| 302 | * written by {@link java.io.ObjectOutput#writeInt(int)} | ||
| 303 | * | ||
| 304 | * <li>a client socket factory (object of type | ||
| 305 | * <code>java.rmi.server.RMIClientSocketFactory</code>), | ||
| 306 | * written by passing it to an invocation of | ||
| 307 | * <code>writeObject</code> on the stream instance | ||
| 308 | * | ||
| 309 | * <li>the data written as a result of calling | ||
| 310 | * {link java.rmi.server.ObjID#write(java.io.ObjectOutput)} | ||
| 311 | * on the <code>ObjID</code> instance contained in the reference | ||
| 312 | * | ||
| 313 | * <li>the boolean value <code>false</code>, | ||
| 314 | * written by {@link java.io.ObjectOutput#writeBoolean(boolean)} | ||
| 315 | * | ||
| 316 | * </ul> | ||
| 317 | * | ||
| 318 | * <p>For <code>"ActivatableRef"</code> with a | ||
| 319 | * <code>null</code> nested remote reference: | ||
| 320 | * | ||
| 321 | * <ul> | ||
| 322 | * | ||
| 323 | * <li>an instance of | ||
| 324 | * <code>java.rmi.activation.ActivationID</code>, | ||
| 325 | * written by passing it to an invocation of | ||
| 326 | * <code>writeObject</code> on the stream instance | ||
| 327 | * | ||
| 328 | * <li>a zero-length string (<code>""</code>), | ||
| 329 | * written by {@link java.io.ObjectOutput#writeUTF(String)} | ||
| 330 | * | ||
| 331 | * </ul> | ||
| 332 | * | ||
| 333 | * <p>For <code>"ActivatableRef"</code> with a | ||
| 334 | * non-<code>null</code> nested remote reference: | ||
| 335 | * | ||
| 336 | * <ul> | ||
| 337 | * | ||
| 338 | * <li>an instance of | ||
| 339 | * <code>java.rmi.activation.ActivationID</code>, | ||
| 340 | * written by passing it to an invocation of | ||
| 341 | * <code>writeObject</code> on the stream instance | ||
| 342 | * | ||
| 343 | * <li>the external ref type name of the nested remote reference, | ||
| 344 | * which must be <code>"UnicastRef2"</code>, | ||
| 345 | * written by {@link java.io.ObjectOutput#writeUTF(String)} | ||
| 346 | * | ||
| 347 | * <li>the external form of the nested remote reference, | ||
| 348 | * written by invoking its <code>writeExternal</code> method | ||
| 349 | * with the stream instance | ||
| 350 | * (see the description of the external form for | ||
| 351 | * <code>"UnicastRef2"</code> above) | ||
| 352 | * | ||
| 353 | * </ul> | ||
| 354 | * | ||
| 355 | * <p>For <code>"UnicastServerRef"</code> and | ||
| 356 | * <code>"UnicastServerRef2"</code>, no data is written by the | ||
| 357 | * <code>writeExternal</code> method or read by the | ||
| 358 | * <code>readExternal</code> method. | ||
| 359 | */ | ||
| 360 | private void writeObject(java.io.ObjectOutputStream out) | ||
| 361 | throws java.io.IOException, java.lang.ClassNotFoundException | ||
| 362 | { | ||
| 363 | if (ref == null) { | ||
| 364 | throw new java.rmi.MarshalException("Invalid remote object"); | ||
| 365 | } else { | ||
| 366 | String refClassName = ref.getRefClass(out); | ||
| 367 | if (refClassName == null || refClassName.length() == 0) { | ||
| 368 | /* | ||
| 369 | * No reference class name specified, so serialize | ||
| 370 | * remote reference. | ||
| 371 | */ | ||
| 372 | out.writeUTF(""); | ||
| 373 | out.writeObject(ref); | ||
| 374 | } else { | ||
| 375 | /* | ||
| 376 | * Built-in reference class specified, so delegate | ||
| 377 | * to reference to write out its external form. | ||
| 378 | */ | ||
| 379 | out.writeUTF(refClassName); | ||
| 380 | ref.writeExternal(out); | ||
| 381 | } | ||
| 382 | } | ||
| 383 | } | ||
| 384 | |||
| 385 | /** | ||
| 386 | * <code>readObject</code> for custom serialization. | ||
| 387 | * | ||
| 388 | * <p>This method reads this object's serialized form for this class | ||
| 389 | * as follows: | ||
| 390 | * | ||
| 391 | * <p>The <code>readUTF</code> method is invoked on <code>in</code> | ||
| 392 | * to read the external ref type name for the <code>RemoteRef</code> | ||
| 393 | * instance to be filled in to this object's <code>ref</code> field. | ||
| 394 | * If the string returned by <code>readUTF</code> has length zero, | ||
| 395 | * the <code>readObject</code> method is invoked on <code>in</code>, | ||
| 396 | * and than the value returned by <code>readObject</code> is cast to | ||
| 397 | * <code>RemoteRef</code> and this object's <code>ref</code> field is | ||
| 398 | * set to that value. | ||
| 399 | * Otherwise, this object's <code>ref</code> field is set to a | ||
| 400 | * <code>RemoteRef</code> instance that is created of an | ||
| 401 | * implementation-specific class corresponding to the external ref | ||
| 402 | * type name returned by <code>readUTF</code>, and then | ||
| 403 | * the <code>readExternal</code> method is invoked on | ||
| 404 | * this object's <code>ref</code> field. | ||
| 405 | * | ||
| 406 | * <p>If the external ref type name is | ||
| 407 | * <code>"UnicastRef"</code>, <code>"UnicastServerRef"</code>, | ||
| 408 | * <code>"UnicastRef2"</code>, <code>"UnicastServerRef2"</code>, | ||
| 409 | * or <code>"ActivatableRef"</code>, a corresponding | ||
| 410 | * implementation-specific class must be found, and its | ||
| 411 | * <code>readExternal</code> method must read the serial data | ||
| 412 | * for that external ref type name as specified to be written | ||
| 413 | * in the <b>serialData</b> documentation for this class. | ||
| 414 | * If the external ref type name is any other string (of non-zero | ||
| 415 | * length), a <code>ClassNotFoundException</code> will be thrown, | ||
| 416 | * unless the implementation provides an implementation-specific | ||
| 417 | * class corresponding to that external ref type name, in which | ||
| 418 | * case this object's <code>ref</code> field will be set to an | ||
| 419 | * instance of that implementation-specific class. | ||
| 420 | */ | ||
| 421 | private void readObject(java.io.ObjectInputStream in) | ||
| 422 | throws java.io.IOException, java.lang.ClassNotFoundException | ||
| 423 | { | ||
| 424 | String refClassName = in.readUTF(); | ||
| 425 | if (refClassName == null || refClassName.length() == 0) { | ||
| 426 | /* | ||
| 427 | * No reference class name specified, so construct | ||
| 428 | * remote reference from its serialized form. | ||
| 429 | */ | ||
| 430 | ref = (RemoteRef) in.readObject(); | ||
| 431 | } else { | ||
| 432 | /* | ||
| 433 | * Built-in reference class specified, so delegate to | ||
| 434 | * internal reference class to initialize its fields from | ||
| 435 | * its external form. | ||
| 436 | */ | ||
| 437 | String internalRefClassName = | ||
| 438 | RemoteRef.packagePrefix + "." + refClassName; | ||
| 439 | Class refClass = Class.forName(internalRefClassName); | ||
| 440 | try { | ||
| 441 | ref = (RemoteRef) refClass.newInstance(); | ||
| 442 | |||
| 443 | /* | ||
| 444 | * If this step fails, assume we found an internal | ||
| 445 | * class that is not meant to be a serializable ref | ||
| 446 | * type. | ||
| 447 | */ | ||
| 448 | } catch (InstantiationException e) { | ||
| 449 | throw new ClassNotFoundException(internalRefClassName, e); | ||
| 450 | } catch (IllegalAccessException e) { | ||
| 451 | throw new ClassNotFoundException(internalRefClassName, e); | ||
| 452 | } catch (ClassCastException e) { | ||
| 453 | throw new ClassNotFoundException(internalRefClassName, e); | ||
| 454 | } | ||
| 455 | ref.readExternal(in); | ||
| 456 | } | ||
| 457 | } | ||
| 458 | } | ||