Java Collection union and intersection patches benchmarks

benchmark.rb

require "benchmark/ips"

module java::util::Collection
  # support the Ruby intersection method on Java Collection
  def i_1(other)
    # transform self into a LinkedHashSet to remove duplicates and preserve order as defined by the Ruby Array intersection contract
    duped = Java::JavaUtil::LinkedHashSet.new(self)
    duped.retainAll(other)
    duped
  end

  def i_2(other)
    to_a & other
  end

  # support the Ruby union method on Java Collection
  def u_1(other)
    # transform self into a LinkedHashSet to remove duplicates and preserve order as defined by the Ruby Array union contract
    duped = Java::JavaUtil::LinkedHashSet.new(self)
    duped.addAll(other)
    duped
  end

  def u_2(other)
    to_a | other
  end
end

m1 = ["foo1", "foo2", "foo3", "foo4", "foo5", "foo6", "foo7", "foo8", "foo9"]
m2 = ["foo5", "foo6", "foo7", "foo8", "foo9", "foo10", "foo11", "foo12", "foo13"]

Benchmark.ips do |x|
  x.warmup = 30
  x.time = 30

  m = Java::JavaUtil::ArrayList.new(m1)
  x.report("u_1 addAll") do
    m.u_1(m2)
  end

  m = Java::JavaUtil::ArrayList.new(m1)
  x.report("u_2 to_a") do
    m.u_2(m2)
  end

  x.compare!
end

Benchmark.ips do |x|
  x.warmup = 30
  x.time = 30

  m = Java::JavaUtil::ArrayList.new(m1)
  x.report("i_1 retainAll") do
    m.i_1(m2)
  end

  m = Java::JavaUtil::ArrayList.new(m1)
  x.report("i_2 to_a") do
    m.i_2(m2)
  end

  x.compare!
end

Gemfile

source "https://rubygems.org"
gem "benchmark-ips"
 

run.txt

tested on MBP 13r, OSX 10.10.2, Java 8, JRuby 1.7.17

$ bundle exec ruby collection_benchmark.rb

Calculating -------------------------------------
          u_1 addAll    26.113k i/100ms
            u_2 to_a    16.348k i/100ms
-------------------------------------------------
          u_1 addAll    311.945k (± 7.0%) i/s -      9.322M
            u_2 to_a    194.675k (±18.8%) i/s -      5.591M

Comparison:
          u_1 addAll:   311945.3 i/s
            u_2 to_a:   194674.9 i/s - 1.60x slower

Calculating -------------------------------------
       i_1 retainAll    28.592k i/100ms
            i_2 to_a    18.481k i/100ms
-------------------------------------------------
       i_1 retainAll    346.149k (± 6.1%) i/s -     10.350M
            i_2 to_a    226.566k (±22.1%) i/s -      6.376M

Comparison:
       i_1 retainAll:   346148.6 i/s
            i_2 to_a:   226566.3 i/s - 1.53x slower