001    /* ObjectStreamConstants.java -- Interface containing constant values
002       used in reading and writing serialized objects
003       Copyright (C) 1998, 1999, 2003, 2006 Free Software Foundation, Inc.
004    
005    This file is part of GNU Classpath.
006    
007    GNU Classpath is free software; you can redistribute it and/or modify
008    it under the terms of the GNU General Public License as published by
009    the Free Software Foundation; either version 2, or (at your option)
010    any later version.
011     
012    GNU Classpath is distributed in the hope that it will be useful, but
013    WITHOUT ANY WARRANTY; without even the implied warranty of
014    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
015    General Public License for more details.
016    
017    You should have received a copy of the GNU General Public License
018    along with GNU Classpath; see the file COPYING.  If not, write to the
019    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
020    02110-1301 USA.
021    
022    Linking this library statically or dynamically with other modules is
023    making a combined work based on this library.  Thus, the terms and
024    conditions of the GNU General Public License cover the whole
025    combination.
026    
027    As a special exception, the copyright holders of this library give you
028    permission to link this library with independent modules to produce an
029    executable, regardless of the license terms of these independent
030    modules, and to copy and distribute the resulting executable under
031    terms of your choice, provided that you also meet, for each linked
032    independent module, the terms and conditions of the license of that
033    module.  An independent module is a module which is not derived from
034    or based on this library.  If you modify this library, you may extend
035    this exception to your version of the library, but you are not
036    obligated to do so.  If you do not wish to do so, delete this
037    exception statement from your version. */
038    
039    
040    package java.io;
041    
042    /**
043     * This interface contains constants that are used in object
044     * serialization.  This interface is used by <code>ObjectOutputStream</code>,
045     * <code>ObjectInputStream</code>, and <code>ObjectStreamClass</code>.
046     * The values for these constants are specified by the Java library
047     * specification.
048     * 
049     * @since 1.1
050     */
051    public interface ObjectStreamConstants
052    {
053      /** 
054       * The serialization stream protocol version 1. This version was
055       * the default serialization protocol before JDK 1.2.
056       * 
057       * @see ObjectOutputStream#useProtocolVersion(int)
058       * @since 1.2
059       */
060      int PROTOCOL_VERSION_1 = 1;
061      
062      /** 
063       * The serialization stream protocol version 2. This version is
064       * used as the default serialization protocol since JDK 1.2.
065       * 
066       * @see ObjectOutputStream#useProtocolVersion(int)
067       * @since 1.2
068       */
069      int PROTOCOL_VERSION_2 = 2;
070    
071      /**
072       * The magic number that is written as part of the stream header.
073       */
074      short STREAM_MAGIC = (short)0xaced;
075      
076      /**
077       * The stream version number that is written as part of the stream header.
078       * Note that this is different from the protocol version that specifies
079       * the data format for the stream.
080       */
081      short STREAM_VERSION = 5;
082    
083      /**
084       * Token value to designate a <code>null</code> reference in the stream.
085       */
086      byte TC_NULL = (byte)112;            //0x70
087      
088      /**
089       * Token value to designate a reference to an already serialized object.
090       */
091      byte TC_REFERENCE = (byte)113;       //0x71
092      
093      /**
094       * Token value to designate a class descriptor is next in the stream.
095       */
096      byte TC_CLASSDESC = (byte)114;       //0x72
097      
098      /**
099       * Token value to designate a new object is next in the stream. 
100       */
101      byte TC_OBJECT = (byte)115;          //0x73
102      
103      /**
104       * Token value to designate a new string is next in the stream.
105       */
106      byte TC_STRING = (byte)116;          //0x74
107      
108      /**
109       * Token value to designate a new array is next in the stream.
110       */
111      byte TC_ARRAY = (byte)117;           //0x75
112      
113      /**
114       * Token reference to designate a reference to a class.
115       */
116      byte TC_CLASS = (byte)118;           //0x76
117      
118      /**
119       * Token value to designate a block of primitive data is next in the stream.
120       * The next byte in the stream holds the size of the block (in bytes).
121       */
122      byte TC_BLOCKDATA = (byte)119;       //0x77
123      
124      /**
125       * Token value to designate the end of a block of primitve data.
126       */
127      byte TC_ENDBLOCKDATA = (byte)120;    //0x78
128      
129      /**
130       * Token value to designate a reset of the stream state.
131       */
132      byte TC_RESET = (byte)121;           //0x79
133      
134      /**
135       * Token value to designate a long block of primitive data is next in the
136       * stream. The next long in the stream holds the size of the block
137       * (in bytes). 
138       */
139      byte TC_BLOCKDATALONG = (byte)122;   //0x7A
140      
141      /**
142       * Token value to designate an exception occured during serialization.
143       */
144      byte TC_EXCEPTION = (byte)123;       //0x7B
145      
146      /**
147       * Token value to designate a long string is next in the stream.
148       */
149      byte TC_LONGSTRING = (byte)124;      //0x7C
150      
151      /**
152       * Token value to designate a proxy class descriptor is next in the stream.
153       */
154      byte TC_PROXYCLASSDESC = (byte)125;  //0x7D
155    
156      /**
157       * Token value to designate an enum constant is next in the stream.
158       * 
159       * @since 1.5
160       */
161      byte TC_ENUM = (byte)126;            //0x7E
162      
163      /**
164       * The first token value.
165       */
166      byte TC_BASE = TC_NULL;
167      
168      /**
169       * The last token value.
170       */
171      byte TC_MAX = TC_ENUM;
172    
173      /**
174       * The first handle that will be assigned to an object, for later references.
175       */
176      int baseWireHandle = 0x7e0000;
177    
178      /**
179       * Flag used in <code>ObjectStreamClass</code> to designate that the class
180       * defines the <code>writeObject</code> method.
181       */
182      byte SC_WRITE_METHOD = 0x01;
183      
184      /**
185       * Flag used in <code>ObjectStreamClass</code> to designate that the class
186       * is serializeable.
187       */
188      byte SC_SERIALIZABLE = 0x02;
189      
190      /**
191       * Flag used in <code>ObjectStreamClass</code> to designate that the class
192       * is externalizable.
193       */
194      byte SC_EXTERNALIZABLE = 0x04;
195      
196      /**
197       * Flag used in <code>ObjectStreamClass</code> to designate that
198       * externalizable data is written in block data mode.
199       * 
200       * @since 1.2
201       */
202      byte SC_BLOCK_DATA = 0x08;
203    
204      /**
205       * Flag used in <code>ObjectStreamClass</code> to designate that the class
206       * is an enum constant.
207       * 
208       * @since 1.5
209       */
210      byte SC_ENUM = 0x10;
211      
212      /**
213       * Constant for use with a <code>SecurityManager</code> to check if
214       * substitution of objects is allowed.
215       */
216      SerializablePermission SUBSTITUTION_PERMISSION
217        = new SerializablePermission("enableSubstitution");
218    
219      /**
220       * Constant for use with a <code>SecurityManager</code> to check if
221       * overriding of the <code>writeObject</code> and <code>readObject</code>
222       * methods is allowed.
223       */
224      SerializablePermission SUBCLASS_IMPLEMENTATION_PERMISSION
225        = new SerializablePermission("enableSubclassImplementation");
226    }
227