Class: Java::ObjectInputStream

Inherits:
Object
  • Object
show all
Includes:
ObjectStream
Defined in:
lib/javaobs.rb

Overview

The Ruby version of the Java ObjectInputStream. Creates a Ruby proxy class for each Java Class.

Constant Summary

Constants included from ObjectStream

Java::ObjectStream::PRIM_ARRAY, Java::ObjectStream::PRIM_BOOL, Java::ObjectStream::PRIM_BYTE, Java::ObjectStream::PRIM_CHAR, Java::ObjectStream::PRIM_DOUBLE, Java::ObjectStream::PRIM_FLOAT, Java::ObjectStream::PRIM_INT, Java::ObjectStream::PRIM_LONG, Java::ObjectStream::PRIM_OBJECT, Java::ObjectStream::PRIM_SHORT, Java::ObjectStream::SC_BLOCKDATA, Java::ObjectStream::SC_EXTERNALIZABLE, Java::ObjectStream::SC_SERIALIZABLE, Java::ObjectStream::SC_WRITE_METHOD, Java::ObjectStream::STREAM_MAGIC, Java::ObjectStream::STREAM_VERSION, Java::ObjectStream::TC_ARRAY, Java::ObjectStream::TC_BLOCKDATA, Java::ObjectStream::TC_BLOCKDATALONG, Java::ObjectStream::TC_CLASS, Java::ObjectStream::TC_CLASSDESC, Java::ObjectStream::TC_ENDBLOCKDATA, Java::ObjectStream::TC_EXCEPTION, Java::ObjectStream::TC_LONGSTRING, Java::ObjectStream::TC_NULL, Java::ObjectStream::TC_OBJECT, Java::ObjectStream::TC_PROXYCLASSDESC, Java::ObjectStream::TC_REFERENCE, Java::ObjectStream::TC_RESET, Java::ObjectStream::TC_STRING

Instance Method Summary collapse

Constructor Details

#initialize(str) ⇒ ObjectInputStream

Initialize from a stream.



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# File 'lib/javaobs.rb', line 483

def initialize(str)
  @str = str
  magic =  readUShort
  streamVersion = readShort
  @objects = []

  raise "Bad stream #{magic.to_s(16)}:#{streamVersion.to_s(16)}" if magic != STREAM_MAGIC ||
  streamVersion != STREAM_VERSION

end

Instance Method Details

#defaultReadObject(object) ⇒ Object

Cover method for java method.



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# File 'lib/javaobs.rb', line 414

def defaultReadObject(object)
  readObjectFields(object.class.javaClass, object)
end

#readArray(klass) ⇒ Object

Read an array of objects.



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# File 'lib/javaobs.rb', line 368

def readArray(klass)
  size = readInt
  a = klass.rubyClass.new
  type = klass.arrayType
  1.upto(size) do
    a << readType(type)
  end
  a
end

#readBlockData ⇒ Object

Read a Java block of data with a size and then the following data.



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# File 'lib/javaobs.rb', line 265

def readBlockData
  size = readBlockStart
  data = @str.read(size)
  readBlockEnd
  data
end

#readBlockEnd ⇒ Object

Read the block end tag. Validate it is correct or raise a SerializationError.

Raises:



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# File 'lib/javaobs.rb', line 259

def readBlockEnd
  byte = readByte
  raise SerializationError, "Unexpected byte #{byte}" unless byte == TC_ENDBLOCKDATA
end

#readBlockStart ⇒ Object

Read the block data beginning tag and return the size. We can have a long or short block of data.



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# File 'lib/javaobs.rb', line 242

def readBlockStart
  byte = readByte
  size = nil
  case byte
  when TC_BLOCKDATA
    size = readByte
    
  when TC_BLOCKDATALONG
    size = readInt
    
  else
    raise SerializationError, "Expecting TC_BLOCKDATA, got #{'0x%X' % byte}" unless byte == TC_BLOCKDATA
  end
  size
end

#readBool ⇒ Object 



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# File 'lib/javaobs.rb', line 236

def readBool; @str.read(1)[0] != 0; end

#readByte ⇒ Object 



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# File 'lib/javaobs.rb', line 229

def readByte; @str.read(1)[0]; end

#readClassAnnotation ⇒ Object

Read the class annotation. We do not currently handle annotations.

Raises:



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# File 'lib/javaobs.rb', line 290

def readClassAnnotation
  ebd = readByte
  raise SerializationError, "We do not handle annotations!" unless ebd == TC_ENDBLOCKDATA
end

#readClassData(klass, object = nil) ⇒ Object

Read class data and recursively read parent classes. If the class is externalizable then we call the _readJavaData method to ‘ perform the custom serialization. See Java::Util::Hash and Java::Util::Date for an example.



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# File 'lib/javaobs.rb', line 430

def readClassData(klass, object = nil)
  if object == nil
    object = klass.rubyClass.new()
    @objects << object
  end
  
  readClassData(klass.superClass, object) if (klass.superClass)
  
  if klass.flags == SC_SERIALIZABLE
    readObjectFields(klass, object)
  else
    object._readJavaData(self)
  end
  
  object
end

#readClassDesc ⇒ Object

Read the Java class description and create a Ruby class to proxy it in this name-space. Added special handling for the Date class.



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# File 'lib/javaobs.rb', line 324

def readClassDesc
  name = readString
  uid = readUID
  flags = readByte
  klass = JavaClass.new(name, uid, flags)
  
  @objects << klass
  
  readFields(klass)
  readClassAnnotation
  
  klass.superClass = readObject

  # Create Ruby object representing class
  if name =~ /^[A-Z.]+/i
    # Create the class within the correct module.
    rclass = rubyClassFor(name, klass.superClass.to_s)

    unless rclass.methods.index('javaClass')
      rclass.class_eval "extend JavaObject"
    end
    
    rclass.class_eval "@javaClass = klass"
    vars = klass.fields.map do |f|
      ':' + f.name
    end
    rclass.class_eval "attr_accessor #{vars.join(',')}"
    klass.rubyClass = rclass
  else
    # Arrays
    newName = 'JavaArray' + klass.name[1..klass.name.length]
    unless Java.constants.index(newName)
      rclass = Java.module_eval "#{newName} = Class.new(JavaArray)"
    else
      rclass = Java.const_get(newName)
    end
    rclass.class_eval "@javaClass = klass"
    klass.rubyClass = rclass
  end
  
  klass
end

#readDouble ⇒ Object 



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# File 'lib/javaobs.rb', line 233

def readDouble; @str.read(8).unpack("G")[0]; end

#readFields(klass) ⇒ Object

Read all the fields from the stream and add them to the class.



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# File 'lib/javaobs.rb', line 274

def readFields(klass)
  fieldCount = readShort
  1.upto(fieldCount) do
    type = readByte
    name = readString
    field = JavaField.new(name, type)
    
    # Check for array and object types
    if type == PRIM_OBJECT || type == PRIM_ARRAY
      field.subtype = readObject
    end
    klass.addField(field)
  end
end

#readFloat ⇒ Object 



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# File 'lib/javaobs.rb', line 234

def readFloat; @str.read(4).unpack("g")[0]; end

#readInt ⇒ Object 



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# File 'lib/javaobs.rb', line 232

def readInt; @str.read(4).unpack("i")[0]; end

#readLong ⇒ Object 



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# File 'lib/javaobs.rb', line 238

def readLong; @str.read(8).unpack("Q").first; end

#readObject ⇒ Object

Read an object from the stream.



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# File 'lib/javaobs.rb', line 448

def readObject
  object = nil
  byte = readByte
  case byte
  when TC_OBJECT
    klass = readObject
    object = readClassData(klass)
    
  when TC_REFERENCE
    readShort
    object = @objects[readShort]
    
  when TC_ARRAY
    klass = readObject
    object = readArray(klass)
    @objects << object
    
  when TC_STRING
    object = readString
    @objects << object

  when TC_CLASSDESC
    object = readClassDesc

  when TC_NULL
    object = nil
    
  else
    raise SerializationError, "Unexpected byte #{byte} at #{@str.pos}"
  end

  object
end

#readObjectFields(klass, object) ⇒ Object

Reads the object fields from the stream.



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# File 'lib/javaobs.rb', line 419

def readObjectFields(klass, object)
  klass.fields.each do |f|
    v = readType(f.type, f.subtype, f)
    object.send((f.name + '=').intern, v)
  end
end

#readObjects ⇒ Object

Read all objects in the stream. Calls readObject until the stream eof is reached.



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# File 'lib/javaobs.rb', line 496

def readObjects
  objs = []
  until (@str.eof)
    objs << readObject
  end
  objs
end

#readShort ⇒ Object 



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# File 'lib/javaobs.rb', line 231

def readShort; @str.read(2).unpack("s")[0]; end

#readString ⇒ Object 



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# File 'lib/javaobs.rb', line 235

def readString; @str.read(readShort); end

#readType(type, arrayType = nil, field = nil) ⇒ Object

Read a primitive data type.



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# File 'lib/javaobs.rb', line 379

def readType(type, arrayType = nil, field = nil)
  case type
  when PRIM_BYTE
    readByte
    
  when PRIM_CHAR
    readByte
    
  when PRIM_DOUBLE
    readDouble
    
  when PRIM_FLOAT
    readFloat
    
  when PRIM_INT
    readInt
    
  when PRIM_LONG
    readLong
    
  when PRIM_SHORT
    readShort
    
  when PRIM_BOOL
    readBool
    
  when PRIM_OBJECT, PRIM_ARRAY
    readObject
    
  else
    raise SerializationError, "Unknown type #{type}"
  end
end

#readUID ⇒ Object 



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# File 'lib/javaobs.rb', line 237

def readUID; @str.read(8); end

#readUShort ⇒ Object 



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# File 'lib/javaobs.rb', line 230

def readUShort; @str.read(2).unpack("n")[0]; end

#rubyClassFor(name, super_name) ⇒ Object

Gets or creates a corresponding Ruby class for the Java class. This will drop leading com or java and transform the rest of the dotted names to modules.



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# File 'lib/javaobs.rb', line 298

def rubyClassFor(name, super_name)
  context = name.split('.')
  f, = context
  context.shift if f == 'java' or f == 'com'
  context.map! { |n| n.capitalize! if n !~ /^[A-Z]/o; n }
  kname = context.pop
  
  mod = Java
  context.each do |m|
    unless mod.constants.include?(m)
      mod = mod.module_eval "#{m} = Module.new"
    else
      mod = mod.const_get(m)
    end
  end
  
  unless mod.constants.include?(kname)
    rclass = mod.module_eval "#{kname} = Class.new(#{super_name})"
  else
    rclass = mod.const_get(kname)
  end
  rclass
end