オブジェクト直列化ストリームプロトコル

Javaでオブジェクトをネットワーク越しに転送したりする時に使用するものに、オブジェクトの直列化があります。これはRMIやEJBの呼び出しにも使われている。
今回RMIのトラブルがあり、不具合を解析するためにTCPダンプでデータを取得し、オブジェクト直列化ストリームプロトコルの解析を実施した。
久しぶりにこれを実施したのですが、いつ見てもわかりにくいプロトコルです。
http://java.sun.com/j2se/1.5.0/ja/docs/ja/guide/serialization/spec/protocol.html#10258
整理されていて綺麗なんでしょうが、こっちはマシンではないので、インデントをつけたり並び替えをやって少し見やすくした（つもり）。

stream:
  magic version contents

  magic:
    STREAM_MAGIC

  version:
    STREAM_VERSION

contents:
  content
  contents content

  content:
    object
    blockdata

    blockdata:
      blockdatashort
      blockdatalong

      blockdatashort:
        TC_BLOCKDATA (unsigned byte) (byte)[size]

      blockdatalong:
        TC_BLOCKDATALONG (int) (byte)[size]

object:
  newObject
  newClass
  newArray
  newString
  newEnum
  newClassDesc
  prevObject
  nullReference
  exception
  TC_RESET

newObject:
  TC_OBJECT classDesc newHandle classdata[] // data for each class

  classdata:
    nowrclass                // SC_SERIALIZABLE   & classDescFlag && !(SC_WRITE_METHOD & classDescFlags)
    wrclass objectAnnotation // SC_SERIALIZABLE   & classDescFlag &&   SC_WRITE_METHOD & classDescFlags
    externalContents         // SC_EXTERNALIZABLE & classDescFlag && !(SC_BLOCKDATA    & classDescFlags)
    objectAnnotation         // SC_EXTERNALIZABLE & classDescFlag &&   SC_BLOCKDATA    & classDescFlags

    nowrclass:
      values // fields in order of class descriptor

    wrclass:
      nowrclass

    externalContents: // externalContent written by
      externalContent // writeExternal in PROTOCOL_VERSION_1.
      externalContents externalContent

      externalContent: // Only parseable by readExternal
        (bytes)        // primitive data
        object

    objectAnnotation:
      endBlockData
      contents endBlockData // contents written by writeObject or writeExternal PROTOCOL_VERSION_2.

newClass:
  TC_CLASS classDesc newHandle

newArray:
  TC_ARRAY classDesc newHandle (int) values[size]

newString:
  TC_STRING newHandle (utf)
  TC_LONGSTRING newHandle (long-utf)

newEnum:
  TC_ENUM classDesc newHandle enumConstantName

  enumConstantName:
    (String)object

newClassDesc:
  TC_CLASSDESC className serialVersionUID newHandle classDescInfo
  TC_PROXYCLASSDESC newHandle proxyClassDescInfo

  className:
    (utf)

  classDescInfo:
    classDescFlags fields classAnnotation superClassDesc

    classDescFlags:
      (byte) // Defined in Terminal Symbols and Constants

    fields:
      (short)  fieldDesc[count]

      fieldDesc:
        primitiveDesc
        objectDesc

        primitiveDesc:
          prim_typecode fieldName

          prim_typecode:
            `B'	 // byte
            `C'	 // char
            `D'	 // double
            `F'	 // float
            `I'	 // integer
            `J'	 // long
            `S'	 // short
            `Z'	 // boolean

        objectDesc:
          obj_typecode fieldName className1

          obj_typecode:
            `[`	 // array
            `L'	 // object

          className1:
            (String)object // ThinkPlus USBキ-ボ-ドString containing the field's type, in field descriptor format

        fieldName:
          (utf)

  proxyClassDescInfo:
    (int) proxyInterfaceName[count] classAnnotation
    superClassDesc

    proxyInterfaceName:
      (utf)

  superClassDesc:
    classDesc

  serialVersionUID:
    (long)

  classAnnotation:
    endBlockData
    contents endBlockData // contents written by annotateClass

prevObject:
  TC_REFERENCE (int)handle

nullReference:
  TC_NULL

exception:
  TC_EXCEPTION reset (Throwable)object	  reset

  reset: // The set of known objects is discarded so the objects of the exception do not overlap with the previously sent objects or with objects that may be sent after the exception

values: // The size and types are described by the classDesc for the current object

classDesc:
  newClassDesc
  nullReference
  (ClassDesc)prevObject // an object required to be of type ClassDesc

endBlockData:
  TC_ENDBLOCKDATA

newHandle: // The next number in sequence is assigned to the object being serialized or deserialized