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
26package java.io;
27
28/**
29 * Constants written into the Object Serialization Stream.
30 *
31 * @author  unascribed
32 * @since 1.1
33 */
34public interface ObjectStreamConstants {
35
36    /**
37     * Magic number that is written to the stream header.
38     */
39    static final short STREAM_MAGIC = (short)0xaced;
40
41    /**
42     * Version number that is written to the stream header.
43     */
44    static final 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    static final byte TC_BASE = 0x70;
53
54    /**
55     * Null object reference.
56     */
57    static final byte TC_NULL =         (byte)0x70;
58
59    /**
60     * Reference to an object already written into the stream.
61     */
62    static final byte TC_REFERENCE =    (byte)0x71;
63
64    /**
65     * new Class Descriptor.
66     */
67    static final byte TC_CLASSDESC =    (byte)0x72;
68
69    /**
70     * new Object.
71     */
72    static final byte TC_OBJECT =       (byte)0x73;
73
74    /**
75     * new String.
76     */
77    static final byte TC_STRING =       (byte)0x74;
78
79    /**
80     * new Array.
81     */
82    static final byte TC_ARRAY =        (byte)0x75;
83
84    /**
85     * Reference to Class.
86     */
87    static final 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    static final byte TC_BLOCKDATA =    (byte)0x77;
94
95    /**
96     * End of optional block data blocks for an object.
97     */
98    static final byte TC_ENDBLOCKDATA = (byte)0x78;
99
100    /**
101     * Reset stream context. All handles written into stream are reset.
102     */
103    static final 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    static final byte TC_BLOCKDATALONG= (byte)0x7A;
110
111    /**
112     * Exception during write.
113     */
114    static final byte TC_EXCEPTION =    (byte)0x7B;
115
116    /**
117     * Long string.
118     */
119    static final byte TC_LONGSTRING =   (byte)0x7C;
120
121    /**
122     * new Proxy Class Descriptor.
123     */
124    static final byte TC_PROXYCLASSDESC =       (byte)0x7D;
125
126    /**
127     * new Enum constant.
128     * @since 1.5
129     */
130    static final byte TC_ENUM =         (byte)0x7E;
131
132    /**
133     * Last tag value.
134     */
135    static final byte TC_MAX =          (byte)0x7E;
136
137    /**
138     * First wire handle to be assigned.
139     */
140    static final 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    static final 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    static final byte SC_BLOCK_DATA = 0x08;
161
162    /**
163     * Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
164     */
165    static final byte SC_SERIALIZABLE = 0x02;
166
167    /**
168     * Bit mask for ObjectStreamClass flag. Indicates class is Externalizable.
169     */
170    static final byte SC_EXTERNALIZABLE = 0x04;
171
172    /**
173     * Bit mask for ObjectStreamClass flag. Indicates class is an enum type.
174     * @since 1.5
175     */
176    static final 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    static final 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    static final SerializablePermission SUBCLASS_IMPLEMENTATION_PERMISSION =
201                    new SerializablePermission("enableSubclassImplementation");
202
203    /**
204     * Enable setting the process-wide serial filter.
205     *
206     * @see java.io.ObjectInputFilter.Config#setSerialFilter(ObjectInputFilter)
207     * @since 9
208     */
209    static final SerializablePermission SERIAL_FILTER_PERMISSION =
210            new SerializablePermission("serialFilter");
211
212   /**
213    * A Stream Protocol Version. <p>
214    *
215    * All externalizable data is written in JDK 1.1 external data
216    * format after calling this method. This version is needed to write
217    * streams containing Externalizable data that can be read by
218    * pre-JDK 1.1.6 JVMs.
219    *
220    * @see java.io.ObjectOutputStream#useProtocolVersion(int)
221    * @since 1.2
222    */
223    public static final int PROTOCOL_VERSION_1 = 1;
224
225
226   /**
227    * A Stream Protocol Version. <p>
228    *
229    * This protocol is written by JVM 1.2.
230    *
231    * Externalizable data is written in block data mode and is
232    * terminated with TC_ENDBLOCKDATA. Externalizable class descriptor
233    * flags has SC_BLOCK_DATA enabled. JVM 1.1.6 and greater can
234    * read this format change.
235    *
236    * Enables writing a nonSerializable class descriptor into the
237    * stream. The serialVersionUID of a nonSerializable class is
238    * set to 0L.
239    *
240    * @see java.io.ObjectOutputStream#useProtocolVersion(int)
241    * @see #SC_BLOCK_DATA
242    * @since 1.2
243    */
244    public static final int PROTOCOL_VERSION_2 = 2;
245}
246