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 * Copyright (c) 1996, 2020, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package java.io;

Constants written into the Object Serialization Stream.
Since:
1.1/**
 * Constants written into the Object Serialization Stream.
 *
 * @since 1.1
 */
public interface ObjectStreamConstants {

    
Magic number that is written to the stream header.
/**
     * Magic number that is written to the stream header.
     */
    static final short STREAM_MAGIC = (short)0xaced;

    
Version number that is written to the stream header.
/**
     * Version number that is written to the stream header.
     */
    static final short STREAM_VERSION = 5;

    /* Each item in the stream is preceded by a tag
     */

    
First tag value.
/**
     * First tag value.
     */
    static final byte TC_BASE = 0x70;

    
Null object reference.
/**
     * Null object reference.
     */
    static final byte TC_NULL =         (byte)0x70;

    
Reference to an object already written into the stream.
/**
     * Reference to an object already written into the stream.
     */
    static final byte TC_REFERENCE =    (byte)0x71;

    
new Class Descriptor.
/**
     * new Class Descriptor.
     */
    static final byte TC_CLASSDESC =    (byte)0x72;

    
new Object.
/**
     * new Object.
     */
    static final byte TC_OBJECT =       (byte)0x73;

    
new String.
/**
     * new String.
     */
    static final byte TC_STRING =       (byte)0x74;

    
new Array.
/**
     * new Array.
     */
    static final byte TC_ARRAY =        (byte)0x75;

    
Reference to Class.
/**
     * Reference to Class.
     */
    static final byte TC_CLASS =        (byte)0x76;

    
Block of optional data. Byte following tag indicates number
of bytes in this block data.
/**
     * Block of optional data. Byte following tag indicates number
     * of bytes in this block data.
     */
    static final byte TC_BLOCKDATA =    (byte)0x77;

    
End of optional block data blocks for an object.
/**
     * End of optional block data blocks for an object.
     */
    static final byte TC_ENDBLOCKDATA = (byte)0x78;

    
Reset stream context. All handles written into stream are reset.
/**
     * Reset stream context. All handles written into stream are reset.
     */
    static final byte TC_RESET =        (byte)0x79;

    
long Block data. The long following the tag indicates the
number of bytes in this block data.
/**
     * long Block data. The long following the tag indicates the
     * number of bytes in this block data.
     */
    static final byte TC_BLOCKDATALONG= (byte)0x7A;

    
Exception during write.
/**
     * Exception during write.
     */
    static final byte TC_EXCEPTION =    (byte)0x7B;

    
Long string.
/**
     * Long string.
     */
    static final byte TC_LONGSTRING =   (byte)0x7C;

    
new Proxy Class Descriptor.
/**
     * new Proxy Class Descriptor.
     */
    static final byte TC_PROXYCLASSDESC =       (byte)0x7D;

    
new Enum constant.
Since:
1.5/**
     * new Enum constant.
     * @since 1.5
     */
    static final byte TC_ENUM =         (byte)0x7E;

    
Last tag value.
/**
     * Last tag value.
     */
    static final byte TC_MAX =          (byte)0x7E;

    
First wire handle to be assigned.
/**
     * First wire handle to be assigned.
     */
    static final int baseWireHandle = 0x7e0000;


    /******************************************************/
    /* Bit masks for ObjectStreamClass flag.*/

    
Bit mask for ObjectStreamClass flag. Indicates a Serializable class
defines its own writeObject method.
/**
     * Bit mask for ObjectStreamClass flag. Indicates a Serializable class
     * defines its own writeObject method.
     */
    static final byte SC_WRITE_METHOD = 0x01;

    
Bit mask for ObjectStreamClass flag. Indicates Externalizable data
written in Block Data mode.
Added for PROTOCOL_VERSION_2.
See Also:
PROTOCOL_VERSION_2
Since:
1.2/**
     * Bit mask for ObjectStreamClass flag. Indicates Externalizable data
     * written in Block Data mode.
     * Added for PROTOCOL_VERSION_2.
     *
     * @see #PROTOCOL_VERSION_2
     * @since 1.2
     */
    static final byte SC_BLOCK_DATA = 0x08;

    
Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
/**
     * Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
     */
    static final byte SC_SERIALIZABLE = 0x02;

    
Bit mask for ObjectStreamClass flag. Indicates class is Externalizable.
/**
     * Bit mask for ObjectStreamClass flag. Indicates class is Externalizable.
     */
    static final byte SC_EXTERNALIZABLE = 0x04;

    
Bit mask for ObjectStreamClass flag. Indicates class is an enum type.
Since:
1.5/**
     * Bit mask for ObjectStreamClass flag. Indicates class is an enum type.
     * @since 1.5
     */
    static final byte SC_ENUM = 0x10;


    /* *******************************************************************/
    /* Security permissions */

    
Enable substitution of one object for another during
serialization/deserialization.
See Also:
enableReplaceObject.enableReplaceObject(boolean)
ObjectInputStream.enableResolveObject(boolean)
Since:
1.2/**
     * Enable substitution of one object for another during
     * serialization/deserialization.
     *
     * @see java.io.ObjectOutputStream#enableReplaceObject(boolean)
     * @see java.io.ObjectInputStream#enableResolveObject(boolean)
     * @since 1.2
     */
    static final SerializablePermission SUBSTITUTION_PERMISSION =
                           new SerializablePermission("enableSubstitution");

    
Enable overriding of readObject and writeObject.
See Also:
writeObjectOverride.writeObjectOverride(Object)
ObjectInputStream.readObjectOverride()
Since:
1.2/**
     * Enable overriding of readObject and writeObject.
     *
     * @see java.io.ObjectOutputStream#writeObjectOverride(Object)
     * @see java.io.ObjectInputStream#readObjectOverride()
     * @since 1.2
     */
    static final SerializablePermission SUBCLASS_IMPLEMENTATION_PERMISSION =
                    new SerializablePermission("enableSubclassImplementation");

    
Enable setting the system-wide serial filter.
See Also:
setSerialFilter.setSerialFilter(ObjectInputFilter)
Since:
9/**
     * Enable setting the system-wide serial filter.
     *
     * @see java.io.ObjectInputFilter.Config#setSerialFilter(ObjectInputFilter)
     * @since 9
     */
    static final SerializablePermission SERIAL_FILTER_PERMISSION =
            new SerializablePermission("serialFilter");

   
A Stream Protocol Version. 

All externalizable data is written in JDK 1.1 external data
format after calling this method. This version is needed to write
streams containing Externalizable data that can be read by
pre-JDK 1.1.6 JVMs.
See Also:
useProtocolVersion.useProtocolVersion(int)
Since:
1.2/**
    * A Stream Protocol Version. <p>
    *
    * All externalizable data is written in JDK 1.1 external data
    * format after calling this method. This version is needed to write
    * streams containing Externalizable data that can be read by
    * pre-JDK 1.1.6 JVMs.
    *
    * @see java.io.ObjectOutputStream#useProtocolVersion(int)
    * @since 1.2
    */
    public static final int PROTOCOL_VERSION_1 = 1;


   
A Stream Protocol Version. 

This protocol is written by JVM 1.2.
Externalizable data is written in block data mode and is
terminated with TC_ENDBLOCKDATA. Externalizable class descriptor
flags has SC_BLOCK_DATA enabled. JVM 1.1.6 and greater can
read this format change.
Enables writing a nonSerializable class descriptor into the
stream. The serialVersionUID of a nonSerializable class is
set to 0L.
See Also:
useProtocolVersion.useProtocolVersion(int)
SC_BLOCK_DATA
Since:
1.2/**
    * A Stream Protocol Version. <p>
    *
    * This protocol is written by JVM 1.2.
    *
    * Externalizable data is written in block data mode and is
    * terminated with TC_ENDBLOCKDATA. Externalizable class descriptor
    * flags has SC_BLOCK_DATA enabled. JVM 1.1.6 and greater can
    * read this format change.
    *
    * Enables writing a nonSerializable class descriptor into the
    * stream. The serialVersionUID of a nonSerializable class is
    * set to 0L.
    *
    * @see java.io.ObjectOutputStream#useProtocolVersion(int)
    * @see #SC_BLOCK_DATA
    * @since 1.2
    */
    public static final int PROTOCOL_VERSION_2 = 2;
}