text: /*
   * Copyright (c) 1996, 2019, 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
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.io;
  
  /**
   * Constants written into the Object Serialization Stream.
   *
   * @author  unascribed
   * @since 1.1
   */
  public interface ObjectStreamConstants {
  
      /**
       * 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.
       */
      static final short STREAM_VERSION = 5;
  
      /* Each item in the stream is preceded by a tag
       */
  
      /**
       * First tag value.
       */
      static final byte TC_BASE = 0x70;
  
      /**
       * Null object reference.
       */
      static final byte TC_NULL =         (byte)0x70;
  
      /**
       * Reference to an object already written into the stream.
       */
      static final byte TC_REFERENCE =    (byte)0x71;
  
      /**
       * new Class Descriptor.
       */
      static final byte TC_CLASSDESC =    (byte)0x72;
  
      /**
       * new Object.
       */
      static final byte TC_OBJECT =       (byte)0x73;
  
      /**
       * new String.
       */
      static final byte TC_STRING =       (byte)0x74;
  
      /**
       * new Array.
       */
      static final byte TC_ARRAY =        (byte)0x75;
  
      /**
       * 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.
       */
      static final byte TC_BLOCKDATA =    (byte)0x77;
  
      /**
       * 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.
       */
      static final byte TC_RESET =        (byte)0x79;
  
      /**
       * 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.
       */
      static final byte TC_EXCEPTION =    (byte)0x7B;
  
      /**
       * Long string.
       */
      static final byte TC_LONGSTRING =   (byte)0x7C;
  
      /**
       * new Proxy Class Descriptor.
       */
      static final byte TC_PROXYCLASSDESC =       (byte)0x7D;
  
      /**
       * new Enum constant.
       * @since 1.5
       */
      static final byte TC_ENUM =         (byte)0x7E;
  
      /**
       * Last tag value.
       */
      static final byte TC_MAX =          (byte)0x7E;
  
      /**
       * 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.
       */
      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 #PROTOCOL_VERSION_2
       * @since 1.2
       */
      static final byte SC_BLOCK_DATA = 0x08;
  
      /**
       * Bit mask for ObjectStreamClass flag. Indicates class is Serializable.
       */
      static final byte SC_SERIALIZABLE = 0x02;
  
      /**
       * 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
       */
      static final byte SC_ENUM = 0x10;
  
  
      /* *******************************************************************/
      /* Security permissions */
  
      /**
       * 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 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 java.io.ObjectInputFilter.Config#setSerialFilter(ObjectInputFilter)
       * @since 9
       */
      static final SerializablePermission SERIAL_FILTER_PERMISSION =
              new SerializablePermission("serialFilter");
  
     /**
      * 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. <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;
  }
  