1 /*
   2  * Copyright (c) 1996, 2013, 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 /**
  29  * Constants written into the Object Serialization Stream.
  30  *
  31  * @author  unascribed
  32  * @since 1.1
  33  */
  34 public interface ObjectStreamConstants {
  35 
  36     /**
  37      * Magic number that is written to the stream header.
  38      */
  39     final static short STREAM_MAGIC = (short)0xaced;
  40 
  41     /**
  42      * Version number that is written to the stream header.
  43      */
  44     final static short STREAM_VERSION = 5;
  45 
  46     /* Each item in the stream is preceded by a tag
  47      */
  48 
  49     /**
  50      * First tag value.
  51      */
  52     final static byte TC_BASE = 0x70;
  53 
  54     /**
  55      * Null object reference.
  56      */
  57     final static byte TC_NULL =         (byte)0x70;
  58 
  59     /**
  60      * Reference to an object already written into the stream.
  61      */
  62     final static byte TC_REFERENCE =    (byte)0x71;
  63 
  64     /**
  65      * new Class Descriptor.
  66      */
  67     final static byte TC_CLASSDESC =    (byte)0x72;
  68 
  69     /**
  70      * new Object.
  71      */
  72     final static byte TC_OBJECT =       (byte)0x73;
  73 
  74     /**
  75      * new String.
  76      */
  77     final static byte TC_STRING =       (byte)0x74;
  78 
  79     /**
  80      * new Array.
  81      */
  82     final static byte TC_ARRAY =        (byte)0x75;
  83 
  84     /**
  85      * Reference to Class.
  86      */
  87     final static byte TC_CLASS =        (byte)0x76;
  88 
  89     /**
  90      * Block of optional data. Byte following tag indicates number
  91      * of bytes in this block data.
  92      */
  93     final static byte TC_BLOCKDATA =    (byte)0x77;
  94 
  95     /**
  96      * End of optional block data blocks for an object.
  97      */
  98     final static byte TC_ENDBLOCKDATA = (byte)0x78;
  99 
 100     /**
 101      * Reset stream context. All handles written into stream are reset.
 102      */
 103     final static byte TC_RESET =        (byte)0x79;
 104 
 105     /**
 106      * long Block data. The long following the tag indicates the
 107      * number of bytes in this block data.
 108      */
 109     final static byte TC_BLOCKDATALONG= (byte)0x7A;
 110 
 111     /**
 112      * Exception during write.
 113      */
 114     final static byte TC_EXCEPTION =    (byte)0x7B;
 115 
 116     /**
 117      * Long string.
 118      */
 119     final static byte TC_LONGSTRING =   (byte)0x7C;
 120 
 121     /**
 122      * new Proxy Class Descriptor.
 123      */
 124     final static byte TC_PROXYCLASSDESC =       (byte)0x7D;
 125 
 126     /**
 127      * new Enum constant.
 128      * @since 1.5
 129      */
 130     final static byte TC_ENUM =         (byte)0x7E;
 131 
 132     /**
 133      * Last tag value.
 134      */
 135     final static byte TC_MAX =          (byte)0x7E;
 136 
 137     /**
 138      * First wire handle to be assigned.
 139      */
 140     final static int baseWireHandle = 0x7e0000;
 141 
 142 
 143     /******************************************************/
 144     /* Bit masks for ObjectStreamClass flag.*/
 145 
 146     /**
 147      * Bit mask for ObjectStreamClass flag. Indicates a Serializable class
 148      * defines its own writeObject method.
 149      */
 150     final static byte SC_WRITE_METHOD = 0x01;
 151 
 152     /**
 153      * Bit mask for ObjectStreamClass flag. Indicates Externalizable data
 154      * written in Block Data mode.
 155      * Added for PROTOCOL_VERSION_2.
 156      *
 157      * @see #PROTOCOL_VERSION_2
 158      * @since 1.2
 159      */
 160     final static byte SC_BLOCK_DATA = 0x08;
 161 
 162     /**
 163      * Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
 164      */
 165     final static byte SC_SERIALIZABLE = 0x02;
 166 
 167     /**
 168      * Bit mask for ObjectStreamClass flag. Indicates class is Externalizable.
 169      */
 170     final static byte SC_EXTERNALIZABLE = 0x04;
 171 
 172     /**
 173      * Bit mask for ObjectStreamClass flag. Indicates class is an enum type.
 174      * @since 1.5
 175      */
 176     final static byte SC_ENUM = 0x10;
 177 
 178 
 179     /* *******************************************************************/
 180     /* Security permissions */
 181 
 182     /**
 183      * Enable substitution of one object for another during
 184      * serialization/deserialization.
 185      *
 186      * @see java.io.ObjectOutputStream#enableReplaceObject(boolean)
 187      * @see java.io.ObjectInputStream#enableResolveObject(boolean)
 188      * @since 1.2
 189      */
 190     final static SerializablePermission SUBSTITUTION_PERMISSION =
 191                            new SerializablePermission("enableSubstitution");
 192 
 193     /**
 194      * Enable overriding of readObject and writeObject.
 195      *
 196      * @see java.io.ObjectOutputStream#writeObjectOverride(Object)
 197      * @see java.io.ObjectInputStream#readObjectOverride()
 198      * @since 1.2
 199      */
 200     final static SerializablePermission SUBCLASS_IMPLEMENTATION_PERMISSION =
 201                     new SerializablePermission("enableSubclassImplementation");
 202    /**
 203     * A Stream Protocol Version. <p>
 204     *
 205     * All externalizable data is written in JDK 1.1 external data
 206     * format after calling this method. This version is needed to write
 207     * streams containing Externalizable data that can be read by
 208     * pre-JDK 1.1.6 JVMs.
 209     *
 210     * @see java.io.ObjectOutputStream#useProtocolVersion(int)
 211     * @since 1.2
 212     */
 213     public final static int PROTOCOL_VERSION_1 = 1;
 214 
 215 
 216    /**
 217     * A Stream Protocol Version. <p>
 218     *
 219     * This protocol is written by JVM 1.2.
 220     *
 221     * Externalizable data is written in block data mode and is
 222     * terminated with TC_ENDBLOCKDATA. Externalizable class descriptor
 223     * flags has SC_BLOCK_DATA enabled. JVM 1.1.6 and greater can
 224     * read this format change.
 225     *
 226     * Enables writing a nonSerializable class descriptor into the
 227     * stream. The serialVersionUID of a nonSerializable class is
 228     * set to 0L.
 229     *
 230     * @see java.io.ObjectOutputStream#useProtocolVersion(int)
 231     * @see #SC_BLOCK_DATA
 232     * @since 1.2
 233     */
 234     public final static int PROTOCOL_VERSION_2 = 2;
 235 }