Class: Spark::JavaBridge::Base

Inherits:
Object
  • Object
show all
Includes:
Helper::System
Defined in:
lib/spark/java_bridge/base.rb

Direct Known Subclasses

JRuby, RJB

Constant Summary collapse

JAVA_OBJECTS = 
[
  'java.util.ArrayList',
  'org.apache.spark.SparkConf',
  'org.apache.spark.api.java.JavaSparkContext',
  'org.apache.spark.api.ruby.RubyRDD',
  'org.apache.spark.api.ruby.RubyUtils',
  'org.apache.spark.api.ruby.RubyWorker',
  'org.apache.spark.api.ruby.PairwiseRDD',
  'org.apache.spark.api.ruby.RubyAccumulatorParam',
  'org.apache.spark.api.ruby.RubySerializer',
  'org.apache.spark.api.python.PythonRDD',
  'org.apache.spark.api.python.PythonPartitioner',
  'org.apache.spark.ui.ruby.RubyTab',
  'org.apache.spark.mllib.api.ruby.RubyMLLibAPI',
  'scala.collection.mutable.HashMap',
  :JInteger  => 'java.lang.Integer',
  :JLong     => 'java.lang.Long',
  :JLogger   => 'org.apache.log4j.Logger',
  :JLevel    => 'org.apache.log4j.Level',
  :JPriority => 'org.apache.log4j.Priority',
  :JUtils    => 'org.apache.spark.util.Utils',
  :JStorageLevel => 'org.apache.spark.storage.StorageLevel',
  :JDenseVector => 'org.apache.spark.mllib.linalg.DenseVector',
  :JDenseMatrix => 'org.apache.spark.mllib.linalg.DenseMatrix'
]
JAVA_TEST_OBJECTS = 
[
  'org.apache.spark.mllib.api.ruby.RubyMLLibUtilAPI'
]
RUBY_TO_JAVA_SKIP = 
[Fixnum, Integer]

Instance Method Summary collapse

Methods included from Helper::System

included

Constructor Details

#initialize(target) ⇒ Base

Returns a new instance of Base.



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# File 'lib/spark/java_bridge/base.rb', line 44

def initialize(target)
  @target = target
end

Instance Method Details

#call(klass, method, *args) ⇒ Object

Call java object



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# File 'lib/spark/java_bridge/base.rb', line 73

def call(klass, method, *args)
  # To java
  args.map!{|item| to_java(item)}

  # Call java
  result = klass.__send__(method, *args)

  # To ruby
  to_ruby(result)
end

#import_all ⇒ Object

Import all important classes into Objects



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# File 'lib/spark/java_bridge/base.rb', line 49

def import_all
  return if @imported

  java_objects.each do |name, klass|
    import(name, klass)
  end

  @imported = true
  nil
end

#import_all_test ⇒ Object

Import classes for testing



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# File 'lib/spark/java_bridge/base.rb', line 61

def import_all_test
  return if @imported_test

  java_test_objects.each do |name, klass|
    import(name, klass)
  end

  @imported_test = true
  nil
end

#to_java(object) ⇒ Object Also known as: ruby_to_java 



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# File 'lib/spark/java_bridge/base.rb', line 97

def to_java(object)
  if RUBY_TO_JAVA_SKIP.include?(object.class)
    # Some object are convert automatically
    # This is for preventing errors
    # For example: jruby store integer as long so 1.to_java is Long
    object
  elsif object.respond_to?(:to_java)
    object.to_java
  elsif object.is_a?(Array)
    to_java_array_list(object)
  else
    object
  end
end

#to_java_array_list(array) ⇒ Object 



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# File 'lib/spark/java_bridge/base.rb', line 84

def to_java_array_list(array)
  array_list = ArrayList.new
  array.each do |item|
    array_list.add(to_java(item))
  end
  array_list
end

#to_long(number) ⇒ Object 



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# File 'lib/spark/java_bridge/base.rb', line 92

def to_long(number)
  return nil if number.nil?
  JLong.new(number)
end

#to_ruby(object) ⇒ Object Also known as: java_to_ruby

Array problem:

Rjb:   object.toArray -> Array
Jruby: object.toArray -> java.lang.Object



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# File 'lib/spark/java_bridge/base.rb', line 116

def to_ruby(object)
  if java_object?(object)
    class_name = object.getClass.getSimpleName
    case class_name
    when 'ArraySeq'
      result = []
      iterator = object.iterator
      while iterator.hasNext
        result << to_ruby(iterator.next)
      end
      result
    when 'Map2', 'Map3', 'Map4', 'HashTrieMap'
      Hash[
        object.toSeq.array.to_a.map!{|item| [item._1, item._2]}
      ]
    when 'SeqWrapper'; object.toArray.to_a.map!{|item| to_ruby(item)}
    when 'ofRef';      object.array.to_a.map!{|item| to_ruby(item)} # WrappedArray$ofRef
    when 'LabeledPoint'; Spark::Mllib::LabeledPoint.from_java(object)
    when 'DenseVector';  Spark::Mllib::DenseVector.from_java(object)
    when 'KMeansModel';  Spark::Mllib::KMeansModel.from_java(object)
    when 'DenseMatrix';  Spark::Mllib::DenseMatrix.from_java(object)
    else
      # Some RDD
      if class_name != 'JavaRDD' && class_name.end_with?('RDD')
        object = object.toJavaRDD
        class_name = 'JavaRDD'
      end

      # JavaRDD
      if class_name == 'JavaRDD'
        jrdd = RubyRDD.toRuby(object)

        serializer = Spark::Serializer.build { __batched__(__marshal__) }
        serializer = Spark::Serializer.build { __batched__(__marshal__, 2) }

        return Spark::RDD.new(jrdd, Spark.sc, serializer, deserializer)
      end

      # Unknow
      Spark.logger.warn("Java object '#{object.getClass.name}' was not converted.")
      object
    end

  else
    # Already transfered
    object
  end
end