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| 1 | +/* | |
| 2 | + * Copyright (c) 1996, 2006, 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.io; | |
| 27 | + | |
| 28 | +import java.lang.reflect.Field; | |
| 29 | + | |
| 30 | +/** | |
| 31 | + * A description of a Serializable field from a Serializable class. An array | |
| 32 | + * of ObjectStreamFields is used to declare the Serializable fields of a class. | |
| 33 | + * | |
| 34 | + * @author Mike Warres | |
| 35 | + * @author Roger Riggs | |
| 36 | + * @see ObjectStreamClass | |
| 37 | + * @since 1.2 | |
| 38 | + */ | |
| 39 | +public class ObjectStreamField | |
| 40 | + implements Comparable<Object> | |
| 41 | +{ | |
| 42 | + | |
| 43 | + /** field name */ | |
| 44 | + private final String name; | |
| 45 | + /** canonical JVM signature of field type */ | |
| 46 | + private final String signature; | |
| 47 | + /** field type (Object.class if unknown non-primitive type) */ | |
| 48 | + private final Class<?> type; | |
| 49 | + /** whether or not to (de)serialize field values as unshared */ | |
| 50 | + private final boolean unshared; | |
| 51 | + /** corresponding reflective field object, if any */ | |
| 52 | + private final Field field; | |
| 53 | + /** offset of field value in enclosing field group */ | |
| 54 | + private int offset = 0; | |
| 55 | + | |
| 56 | + /** | |
| 57 | + * Create a Serializable field with the specified type. This field should | |
| 58 | + * be documented with a <code>serialField</code> tag. | |
| 59 | + * | |
| 60 | + * @param name the name of the serializable field | |
| 61 | + * @param type the <code>Class</code> object of the serializable field | |
| 62 | + */ | |
| 63 | + public ObjectStreamField(String name, Class<?> type) { | |
| 64 | + this(name, type, false); | |
| 65 | + } | |
| 66 | + | |
| 67 | + /** | |
| 68 | + * Creates an ObjectStreamField representing a serializable field with the | |
| 69 | + * given name and type. If unshared is false, values of the represented | |
| 70 | + * field are serialized and deserialized in the default manner--if the | |
| 71 | + * field is non-primitive, object values are serialized and deserialized as | |
| 72 | + * if they had been written and read by calls to writeObject and | |
| 73 | + * readObject. If unshared is true, values of the represented field are | |
| 74 | + * serialized and deserialized as if they had been written and read by | |
| 75 | + * calls to writeUnshared and readUnshared. | |
| 76 | + * | |
| 77 | + * @param name field name | |
| 78 | + * @param type field type | |
| 79 | + * @param unshared if false, write/read field values in the same manner | |
| 80 | + * as writeObject/readObject; if true, write/read in the same | |
| 81 | + * manner as writeUnshared/readUnshared | |
| 82 | + * @since 1.4 | |
| 83 | + */ | |
| 84 | + public ObjectStreamField(String name, Class<?> type, boolean unshared) { | |
| 85 | + if (name == null) { | |
| 86 | + throw new NullPointerException(); | |
| 87 | + } | |
| 88 | + this.name = name; | |
| 89 | + this.type = type; | |
| 90 | + this.unshared = unshared; | |
| 91 | + signature = getClassSignature(type).intern(); | |
| 92 | + field = null; | |
| 93 | + } | |
| 94 | + | |
| 95 | + /** | |
| 96 | + * Creates an ObjectStreamField representing a field with the given name, | |
| 97 | + * signature and unshared setting. | |
| 98 | + */ | |
| 99 | + ObjectStreamField(String name, String signature, boolean unshared) { | |
| 100 | + if (name == null) { | |
| 101 | + throw new NullPointerException(); | |
| 102 | + } | |
| 103 | + this.name = name; | |
| 104 | + this.signature = signature.intern(); | |
| 105 | + this.unshared = unshared; | |
| 106 | + field = null; | |
| 107 | + | |
| 108 | + switch (signature.charAt(0)) { | |
| 109 | + case 'Z': type = Boolean.TYPE; break; | |
| 110 | + case 'B': type = Byte.TYPE; break; | |
| 111 | + case 'C': type = Character.TYPE; break; | |
| 112 | + case 'S': type = Short.TYPE; break; | |
| 113 | + case 'I': type = Integer.TYPE; break; | |
| 114 | + case 'J': type = Long.TYPE; break; | |
| 115 | + case 'F': type = Float.TYPE; break; | |
| 116 | + case 'D': type = Double.TYPE; break; | |
| 117 | + case 'L': | |
| 118 | + case '[': type = Object.class; break; | |
| 119 | + default: throw new IllegalArgumentException("illegal signature"); | |
| 120 | + } | |
| 121 | + } | |
| 122 | + | |
| 123 | + /** | |
| 124 | + * Creates an ObjectStreamField representing the given field with the | |
| 125 | + * specified unshared setting. For compatibility with the behavior of | |
| 126 | + * earlier serialization implementations, a "showType" parameter is | |
| 127 | + * necessary to govern whether or not a getType() call on this | |
| 128 | + * ObjectStreamField (if non-primitive) will return Object.class (as | |
| 129 | + * opposed to a more specific reference type). | |
| 130 | + */ | |
| 131 | + ObjectStreamField(Field field, boolean unshared, boolean showType) { | |
| 132 | + this.field = field; | |
| 133 | + this.unshared = unshared; | |
| 134 | + name = field.getName(); | |
| 135 | + Class<?> ftype = field.getType(); | |
| 136 | + type = (showType || ftype.isPrimitive()) ? ftype : Object.class; | |
| 137 | + signature = getClassSignature(ftype).intern(); | |
| 138 | + } | |
| 139 | + | |
| 140 | + /** | |
| 141 | + * Get the name of this field. | |
| 142 | + * | |
| 143 | + * @return a <code>String</code> representing the name of the serializable | |
| 144 | + * field | |
| 145 | + */ | |
| 146 | + public String getName() { | |
| 147 | + return name; | |
| 148 | + } | |
| 149 | + | |
| 150 | + /** | |
| 151 | + * Get the type of the field. If the type is non-primitive and this | |
| 152 | + * <code>ObjectStreamField</code> was obtained from a deserialized {@link | |
| 153 | + * ObjectStreamClass} instance, then <code>Object.class</code> is returned. | |
| 154 | + * Otherwise, the <code>Class</code> object for the type of the field is | |
| 155 | + * returned. | |
| 156 | + * | |
| 157 | + * @return a <code>Class</code> object representing the type of the | |
| 158 | + * serializable field | |
| 159 | + */ | |
| 160 | + public Class<?> getType() { | |
| 161 | + return type; | |
| 162 | + } | |
| 163 | + | |
| 164 | + /** | |
| 165 | + * Returns character encoding of field type. The encoding is as follows: | |
| 166 | + * <blockquote><pre> | |
| 167 | + * B byte | |
| 168 | + * C char | |
| 169 | + * D double | |
| 170 | + * F float | |
| 171 | + * I int | |
| 172 | + * J long | |
| 173 | + * L class or interface | |
| 174 | + * S short | |
| 175 | + * Z boolean | |
| 176 | + * [ array | |
| 177 | + * </pre></blockquote> | |
| 178 | + * | |
| 179 | + * @return the typecode of the serializable field | |
| 180 | + */ | |
| 181 | + // REMIND: deprecate? | |
| 182 | + public char getTypeCode() { | |
| 183 | + return signature.charAt(0); | |
| 184 | + } | |
| 185 | + | |
| 186 | + /** | |
| 187 | + * Return the JVM type signature. | |
| 188 | + * | |
| 189 | + * @return null if this field has a primitive type. | |
| 190 | + */ | |
| 191 | + // REMIND: deprecate? | |
| 192 | + public String getTypeString() { | |
| 193 | + return isPrimitive() ? null : signature; | |
| 194 | + } | |
| 195 | + | |
| 196 | + /** | |
| 197 | + * Offset of field within instance data. | |
| 198 | + * | |
| 199 | + * @return the offset of this field | |
| 200 | + * @see #setOffset | |
| 201 | + */ | |
| 202 | + // REMIND: deprecate? | |
| 203 | + public int getOffset() { | |
| 204 | + return offset; | |
| 205 | + } | |
| 206 | + | |
| 207 | + /** | |
| 208 | + * Offset within instance data. | |
| 209 | + * | |
| 210 | + * @param offset the offset of the field | |
| 211 | + * @see #getOffset | |
| 212 | + */ | |
| 213 | + // REMIND: deprecate? | |
| 214 | + protected void setOffset(int offset) { | |
| 215 | + this.offset = offset; | |
| 216 | + } | |
| 217 | + | |
| 218 | + /** | |
| 219 | + * Return true if this field has a primitive type. | |
| 220 | + * | |
| 221 | + * @return true if and only if this field corresponds to a primitive type | |
| 222 | + */ | |
| 223 | + // REMIND: deprecate? | |
| 224 | + public boolean isPrimitive() { | |
| 225 | + char tcode = signature.charAt(0); | |
| 226 | + return ((tcode != 'L') && (tcode != '[')); | |
| 227 | + } | |
| 228 | + | |
| 229 | + /** | |
| 230 | + * Returns boolean value indicating whether or not the serializable field | |
| 231 | + * represented by this ObjectStreamField instance is unshared. | |
| 232 | + * | |
| 233 | + * @since 1.4 | |
| 234 | + */ | |
| 235 | + public boolean isUnshared() { | |
| 236 | + return unshared; | |
| 237 | + } | |
| 238 | + | |
| 239 | + /** | |
| 240 | + * Compare this field with another <code>ObjectStreamField</code>. Return | |
| 241 | + * -1 if this is smaller, 0 if equal, 1 if greater. Types that are | |
| 242 | + * primitives are "smaller" than object types. If equal, the field names | |
| 243 | + * are compared. | |
| 244 | + */ | |
| 245 | + // REMIND: deprecate? | |
| 246 | + public int compareTo(Object obj) { | |
| 247 | + ObjectStreamField other = (ObjectStreamField) obj; | |
| 248 | + boolean isPrim = isPrimitive(); | |
| 249 | + if (isPrim != other.isPrimitive()) { | |
| 250 | + return isPrim ? -1 : 1; | |
| 251 | + } | |
| 252 | + return name.compareTo(other.name); | |
| 253 | + } | |
| 254 | + | |
| 255 | + /** | |
| 256 | + * Return a string that describes this field. | |
| 257 | + */ | |
| 258 | + public String toString() { | |
| 259 | + return signature + ' ' + name; | |
| 260 | + } | |
| 261 | + | |
| 262 | + /** | |
| 263 | + * Returns field represented by this ObjectStreamField, or null if | |
| 264 | + * ObjectStreamField is not associated with an actual field. | |
| 265 | + */ | |
| 266 | + Field getField() { | |
| 267 | + return field; | |
| 268 | + } | |
| 269 | + | |
| 270 | + /** | |
| 271 | + * Returns JVM type signature of field (similar to getTypeString, except | |
| 272 | + * that signature strings are returned for primitive fields as well). | |
| 273 | + */ | |
| 274 | + String getSignature() { | |
| 275 | + return signature; | |
| 276 | + } | |
| 277 | + | |
| 278 | + /** | |
| 279 | + * Returns JVM type signature for given class. | |
| 280 | + */ | |
| 281 | + private static String getClassSignature(Class<?> cl) { | |
| 282 | + StringBuilder sbuf = new StringBuilder(); | |
| 283 | + while (cl.isArray()) { | |
| 284 | + sbuf.append('['); | |
| 285 | + cl = cl.getComponentType(); | |
| 286 | + } | |
| 287 | + if (cl.isPrimitive()) { | |
| 288 | + if (cl == Integer.TYPE) { | |
| 289 | + sbuf.append('I'); | |
| 290 | + } else if (cl == Byte.TYPE) { | |
| 291 | + sbuf.append('B'); | |
| 292 | + } else if (cl == Long.TYPE) { | |
| 293 | + sbuf.append('J'); | |
| 294 | + } else if (cl == Float.TYPE) { | |
| 295 | + sbuf.append('F'); | |
| 296 | + } else if (cl == Double.TYPE) { | |
| 297 | + sbuf.append('D'); | |
| 298 | + } else if (cl == Short.TYPE) { | |
| 299 | + sbuf.append('S'); | |
| 300 | + } else if (cl == Character.TYPE) { | |
| 301 | + sbuf.append('C'); | |
| 302 | + } else if (cl == Boolean.TYPE) { | |
| 303 | + sbuf.append('Z'); | |
| 304 | + } else if (cl == Void.TYPE) { | |
| 305 | + sbuf.append('V'); | |
| 306 | + } else { | |
| 307 | + throw new InternalError(); | |
| 308 | + } | |
| 309 | + } else { | |
| 310 | + sbuf.append('L' + cl.getName().replace('.', '/') + ';'); | |
| 311 | + } | |
| 312 | + return sbuf.toString(); | |
| 313 | + } | |
| 314 | +} | |