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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 2005, 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; | ||
| 27 | |||
| 28 | import java.io.ByteArrayInputStream; | ||
| 29 | import java.io.ByteArrayOutputStream; | ||
| 30 | import java.io.IOException; | ||
| 31 | import java.io.InputStream; | ||
| 32 | import java.io.ObjectInputStream; | ||
| 33 | import java.io.ObjectOutputStream; | ||
| 34 | import java.io.ObjectStreamConstants; | ||
| 35 | import java.io.OutputStream; | ||
| 36 | import java.io.Serializable; | ||
| 37 | import sun.rmi.server.MarshalInputStream; | ||
| 38 | import sun.rmi.server.MarshalOutputStream; | ||
| 39 | |||
| 40 | /** | ||
| 41 | * A <code>MarshalledObject</code> contains a byte stream with the serialized | ||
| 42 | * representation of an object given to its constructor. The <code>get</code> | ||
| 43 | * method returns a new copy of the original object, as deserialized from | ||
| 44 | * the contained byte stream. The contained object is serialized and | ||
| 45 | * deserialized with the same serialization semantics used for marshaling | ||
| 46 | * and unmarshaling parameters and return values of RMI calls: When the | ||
| 47 | * serialized form is created: | ||
| 48 | * | ||
| 49 | * <ul> | ||
| 50 | * <li> classes are annotated with a codebase URL from where the class | ||
| 51 | * can be loaded (if available), and | ||
| 52 | * <li> any remote object in the <code>MarshalledObject</code> is | ||
| 53 | * represented by a serialized instance of its stub. | ||
| 54 | * </ul> | ||
| 55 | * | ||
| 56 | * <p>When copy of the object is retrieved (via the <code>get</code> method), | ||
| 57 | * if the class is not available locally, it will be loaded from the | ||
| 58 | * appropriate location (specified the URL annotated with the class descriptor | ||
| 59 | * when the class was serialized. | ||
| 60 | * | ||
| 61 | * <p><code>MarshalledObject</code> facilitates passing objects in RMI calls | ||
| 62 | * that are not automatically deserialized immediately by the remote peer. | ||
| 63 | * | ||
| 64 | * @param <T> the type of the object contained in this | ||
| 65 | * <code>MarshalledObject</code> | ||
| 66 | * | ||
| 67 | * @author Ann Wollrath | ||
| 68 | * @author Peter Jones | ||
| 69 | * @since 1.2 | ||
| 70 | */ | ||
| 71 | public final class MarshalledObject<T> implements Serializable { | ||
| 72 | /** | ||
| 73 | * @serial Bytes of serialized representation. If <code>objBytes</code> is | ||
| 74 | * <code>null</code> then the object marshalled was a <code>null</code> | ||
| 75 | * reference. | ||
| 76 | */ | ||
| 77 | private byte[] objBytes = null; | ||
| 78 | |||
| 79 | /** | ||
| 80 | * @serial Bytes of location annotations, which are ignored by | ||
| 81 | * <code>equals</code>. If <code>locBytes</code> is null, there were no | ||
| 82 | * non-<code>null</code> annotations during marshalling. | ||
| 83 | */ | ||
| 84 | private byte[] locBytes = null; | ||
| 85 | |||
| 86 | /** | ||
| 87 | * @serial Stored hash code of contained object. | ||
| 88 | * | ||
| 89 | * @see #hashCode | ||
| 90 | */ | ||
| 91 | private int hash; | ||
| 92 | |||
| 93 | /** Indicate compatibility with 1.2 version of class. */ | ||
| 94 | private static final long serialVersionUID = 8988374069173025854L; | ||
| 95 | |||
| 96 | /** | ||
| 97 | * Creates a new <code>MarshalledObject</code> that contains the | ||
| 98 | * serialized representation of the current state of the supplied object. | ||
| 99 | * The object is serialized with the semantics used for marshaling | ||
| 100 | * parameters for RMI calls. | ||
| 101 | * | ||
| 102 | * @param obj the object to be serialized (must be serializable) | ||
| 103 | * @exception IOException if an <code>IOException</code> occurs; an | ||
| 104 | * <code>IOException</code> may occur if <code>obj</code> is not | ||
| 105 | * serializable. | ||
| 106 | * @since 1.2 | ||
| 107 | */ | ||
| 108 | public MarshalledObject(T obj) throws IOException { | ||
| 109 | if (obj == null) { | ||
| 110 | hash = 13; | ||
| 111 | return; | ||
| 112 | } | ||
| 113 | |||
| 114 | ByteArrayOutputStream bout = new ByteArrayOutputStream(); | ||
| 115 | ByteArrayOutputStream lout = new ByteArrayOutputStream(); | ||
| 116 | MarshalledObjectOutputStream out = | ||
| 117 | new MarshalledObjectOutputStream(bout, lout); | ||
| 118 | out.writeObject(obj); | ||
| 119 | out.flush(); | ||
| 120 | objBytes = bout.toByteArray(); | ||
| 121 | // locBytes is null if no annotations | ||
| 122 | locBytes = (out.hadAnnotations() ? lout.toByteArray() : null); | ||
| 123 | |||
| 124 | /* | ||
| 125 | * Calculate hash from the marshalled representation of object | ||
| 126 | * so the hashcode will be comparable when sent between VMs. | ||
| 127 | */ | ||
| 128 | int h = 0; | ||
| 129 | for (int i = 0; i < objBytes.length; i++) { | ||
| 130 | h = 31 * h + objBytes[i]; | ||
| 131 | } | ||
| 132 | hash = h; | ||
| 133 | } | ||
| 134 | |||
| 135 | /** | ||
| 136 | * Returns a new copy of the contained marshalledobject. The internal | ||
| 137 | * representation is deserialized with the semantics used for | ||
| 138 | * unmarshaling paramters for RMI calls. | ||
| 139 | * | ||
| 140 | * @return a copy of the contained object | ||
| 141 | * @exception IOException if an <code>IOException</code> occurs while | ||
| 142 | * deserializing the object from its internal representation. | ||
| 143 | * @exception ClassNotFoundException if a | ||
| 144 | * <code>ClassNotFoundException</code> occurs while deserializing the | ||
| 145 | * object from its internal representation. | ||
| 146 | * could not be found | ||
| 147 | * @since 1.2 | ||
| 148 | */ | ||
| 149 | public T get() throws IOException, ClassNotFoundException { | ||
| 150 | if (objBytes == null) // must have been a null object | ||
| 151 | return null; | ||
| 152 | |||
| 153 | ByteArrayInputStream bin = new ByteArrayInputStream(objBytes); | ||
| 154 | // locBytes is null if no annotations | ||
| 155 | ByteArrayInputStream lin = | ||
| 156 | (locBytes == null ? null : new ByteArrayInputStream(locBytes)); | ||
| 157 | MarshalledObjectInputStream in = | ||
| 158 | new MarshalledObjectInputStream(bin, lin); | ||
| 159 | T obj = (T) in.readObject(); | ||
| 160 | in.close(); | ||
| 161 | return obj; | ||
| 162 | } | ||
| 163 | |||
| 164 | /** | ||
| 165 | * Return a hash code for this <code>MarshalledObject</code>. | ||
| 166 | * | ||
| 167 | * @return a hash code | ||
| 168 | */ | ||
| 169 | public int hashCode() { | ||
| 170 | return hash; | ||
| 171 | } | ||
| 172 | |||
| 173 | /** | ||
| 174 | * Compares this <code>MarshalledObject</code> to another object. | ||
| 175 | * Returns true if and only if the argument refers to a | ||
| 176 | * <code>MarshalledObject</code> that contains exactly the same | ||
| 177 | * serialized representation of an object as this one does. The | ||
| 178 | * comparison ignores any class codebase annotation, meaning that | ||
| 179 | * two objects are equivalent if they have the same serialized | ||
| 180 | * representation <i>except</i> for the codebase of each class | ||
| 181 | * in the serialized representation. | ||
| 182 | * | ||
| 183 | * @param obj the object to compare with this <code>MarshalledObject</code> | ||
| 184 | * @return <code>true</code> if the argument contains an equaivalent | ||
| 185 | * serialized object; <code>false</code> otherwise | ||
| 186 | * @since 1.2 | ||
| 187 | */ | ||
| 188 | public boolean equals(Object obj) { | ||
| 189 | if (obj == this) | ||
| 190 | return true; | ||
| 191 | |||
| 192 | if (obj != null && obj instanceof MarshalledObject) { | ||
| 193 | MarshalledObject other = (MarshalledObject) obj; | ||
| 194 | |||
| 195 | // if either is a ref to null, both must be | ||
| 196 | if (objBytes == null || other.objBytes == null) | ||
| 197 | return objBytes == other.objBytes; | ||
| 198 | |||
| 199 | // quick, easy test | ||
| 200 | if (objBytes.length != other.objBytes.length) | ||
| 201 | return false; | ||
| 202 | |||
| 203 | //!! There is talk about adding an array comparision method | ||
| 204 | //!! at 1.2 -- if so, this should be rewritten. -arnold | ||
| 205 | for (int i = 0; i < objBytes.length; ++i) { | ||
| 206 | if (objBytes[i] != other.objBytes[i]) | ||
| 207 | return false; | ||
| 208 | } | ||
| 209 | return true; | ||
| 210 | } else { | ||
| 211 | return false; | ||
| 212 | } | ||
| 213 | } | ||
| 214 | |||
| 215 | /** | ||
| 216 | * This class is used to marshal objects for | ||
| 217 | * <code>MarshalledObject</code>. It places the location annotations | ||
| 218 | * to one side so that two <code>MarshalledObject</code>s can be | ||
| 219 | * compared for equality if they differ only in location | ||
| 220 | * annotations. Objects written using this stream should be read back | ||
| 221 | * from a <code>MarshalledObjectInputStream</code>. | ||
| 222 | * | ||
| 223 | * @see java.rmi.MarshalledObject | ||
| 224 | * @see MarshalledObjectInputStream | ||
| 225 | */ | ||
| 226 | private static class MarshalledObjectOutputStream | ||
| 227 | extends MarshalOutputStream | ||
| 228 | { | ||
| 229 | /** The stream on which location objects are written. */ | ||
| 230 | private ObjectOutputStream locOut; | ||
| 231 | |||
| 232 | /** <code>true</code> if non-<code>null</code> annotations are | ||
| 233 | * written. | ||
| 234 | */ | ||
| 235 | private boolean hadAnnotations; | ||
| 236 | |||
| 237 | /** | ||
| 238 | * Creates a new <code>MarshalledObjectOutputStream</code> whose | ||
| 239 | * non-location bytes will be written to <code>objOut</code> and whose | ||
| 240 | * location annotations (if any) will be written to | ||
| 241 | * <code>locOut</code>. | ||
| 242 | */ | ||
| 243 | MarshalledObjectOutputStream(OutputStream objOut, OutputStream locOut) | ||
| 244 | throws IOException | ||
| 245 | { | ||
| 246 | super(objOut); | ||
| 247 | this.useProtocolVersion(ObjectStreamConstants.PROTOCOL_VERSION_2); | ||
| 248 | this.locOut = new ObjectOutputStream(locOut); | ||
| 249 | hadAnnotations = false; | ||
| 250 | } | ||
| 251 | |||
| 252 | /** | ||
| 253 | * Returns <code>true</code> if any non-<code>null</code> location | ||
| 254 | * annotations have been written to this stream. | ||
| 255 | */ | ||
| 256 | boolean hadAnnotations() { | ||
| 257 | return hadAnnotations; | ||
| 258 | } | ||
| 259 | |||
| 260 | /** | ||
| 261 | * Overrides MarshalOutputStream.writeLocation implementation to write | ||
| 262 | * annotations to the location stream. | ||
| 263 | */ | ||
| 264 | protected void writeLocation(String loc) throws IOException { | ||
| 265 | hadAnnotations |= (loc != null); | ||
| 266 | locOut.writeObject(loc); | ||
| 267 | } | ||
| 268 | |||
| 269 | |||
| 270 | public void flush() throws IOException { | ||
| 271 | super.flush(); | ||
| 272 | locOut.flush(); | ||
| 273 | } | ||
| 274 | } | ||
| 275 | |||
| 276 | /** | ||
| 277 | * The counterpart to <code>MarshalledObjectOutputStream</code>. | ||
| 278 | * | ||
| 279 | * @see MarshalledObjectOutputStream | ||
| 280 | */ | ||
| 281 | private static class MarshalledObjectInputStream | ||
| 282 | extends MarshalInputStream | ||
| 283 | { | ||
| 284 | /** | ||
| 285 | * The stream from which annotations will be read. If this is | ||
| 286 | * <code>null</code>, then all annotations were <code>null</code>. | ||
| 287 | */ | ||
| 288 | private ObjectInputStream locIn; | ||
| 289 | |||
| 290 | /** | ||
| 291 | * Creates a new <code>MarshalledObjectInputStream</code> that | ||
| 292 | * reads its objects from <code>objIn</code> and annotations | ||
| 293 | * from <code>locIn</code>. If <code>locIn</code> is | ||
| 294 | * <code>null</code>, then all annotations will be | ||
| 295 | * <code>null</code>. | ||
| 296 | */ | ||
| 297 | MarshalledObjectInputStream(InputStream objIn, InputStream locIn) | ||
| 298 | throws IOException | ||
| 299 | { | ||
| 300 | super(objIn); | ||
| 301 | this.locIn = (locIn == null ? null : new ObjectInputStream(locIn)); | ||
| 302 | } | ||
| 303 | |||
| 304 | /** | ||
| 305 | * Overrides MarshalInputStream.readLocation to return locations from | ||
| 306 | * the stream we were given, or <code>null</code> if we were given a | ||
| 307 | * <code>null</code> location stream. | ||
| 308 | */ | ||
| 309 | protected Object readLocation() | ||
| 310 | throws IOException, ClassNotFoundException | ||
| 311 | { | ||
| 312 | return (locIn == null ? null : locIn.readObject()); | ||
| 313 | } | ||
| 314 | } | ||
| 315 | |||
| 316 | } | ||