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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).
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24  */
25 
26 package java.io;
27 
28 /**
29  * Constants written into the Object Serialization Stream.
30  *
31  * @author  unascribed
32  * @since JDK 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 }
236