dci benchmarks

dci.rb

require 'benchmark'
require 'delegate'

#---------------------------------------------------------------
# ruby normal implementation
#---------------------------------------------------------------
module Mover
  def accelerate(speed:)
    @speed += speed
  end
end

class Car
  include Mover

  attr_reader :speed, :speed_limit

  def initialize(speed: 0, speed_limit:)
    @speed = speed
    @speed_limit = speed_limit
  end
end

def include_module
  car = Car.new(speed: 0, speed_limit: 100)
  car.accelerate(speed: 10)
  car.accelerate(speed: 50)
  car.accelerate(speed: 50)
end

#---------------------------------------------------------------
# using a decorator
#---------------------------------------------------------------
class Car2
  attr_accessor :speed, :speed_limit

  def initialize(speed: 0, speed_limit:)
    @speed = speed
    @speed_limit = speed_limit
  end
end

class Mover2 < SimpleDelegator

  def initialize(car:)
    super(car: car)
  end

  def accelerate(speed:)
    self[:car].speed += speed
  end
end

def decorator
  car2 = Car2.new(speed: 0, speed_limit: 100)
  mover2 = Mover2.new(car: car2)
  mover2.accelerate(speed: 10)
  mover2.accelerate(speed: 50)
  mover2.accelerate(speed: 50)
end

#---------------------------------------------------------------
# extending a module dynamically
#---------------------------------------------------------------
class Car3
  attr_reader :speed, :speed_limit

  def initialize(speed: 0, speed_limit:)
    @speed = speed
    @speed_limit = speed_limit
  end
end

module Mover3
  def accelerate(speed:)
    @speed += speed
  end
end

class MoveContext
  def self.call(movable:, speed:)
    self.new(movable).run(speed)
  end

  def initialize(movable)
    @movable = movable
    @movable.extend(Mover)
  end

  def run(speed)
    #puts "moving at #{@movable.speed} km/h, trying to accelerate"
    if (@movable.speed + speed < @movable.speed_limit)
      @movable.accelerate(speed: speed)
      #puts "now moving at #{@movable.speed} km/h"
    else
      #puts "cannot accelerate anymore"
    end
  end
end

def dci_with_extend
  car = Car3.new(speed: 0, speed_limit: 100)
  MoveContext::call(movable: car, speed: 10)
  MoveContext::call(movable: car, speed: 50)
  MoveContext::call(movable: car, speed: 50)
end

#---------------------------------------------------------------
# 
#---------------------------------------------------------------
module Role
  attr_accessor :role

  def method_missing(method_name, *args, &block)
    if role && role.public_method_defined?(method_name)
      role.instance_method(method_name).bind(self).call(*args, &block)
    else
      super
    end
  end

  def respond_to_missing?(method_name, include_all=false)
    if role && role.public_method_defined?(method_name)
      true
    else
      super
    end
  end

  def play_role(role)
    self.role = role
    yield(self)
  ensure
    self.role = nil
  end
end

class Car4
  include Role

  attr_reader :speed, :speed_limit

  def initialize(speed: 0, speed_limit:)
    @speed = speed
    @speed_limit = speed_limit
  end
end

module Mover4
  def accelerate(speed:)
    @speed += speed
  end
end

def dci_with_binding
  car4 = Car4.new(speed: 0, speed_limit: 100)
  car4.play_role(Mover4) do |c|
    c.accelerate(speed: 10)
    c.accelerate(speed: 50)
    c.accelerate(speed: 50)
  end
end

Benchmark.bm do |x|
  n = 100_000
  padding = 16
  x.report("%#{padding}s" % 'include_module') { 
    n.times { include_module() } 
  }
  x.report("%#{padding}s" % 'decorator') { 
    n.times { decorator() } 
  }
  x.report("%#{padding}s" % 'dci_with_extend') { 
    n.times { dci_with_extend() } 
  }
  x.report("%#{padding}s" % 'dci_with_binding') { 
    n.times { dci_with_binding() } 
  }
end

=begin
       user     system      total        real
  include_module  0.460000   0.010000   0.470000 (  0.463059)
       decorator  0.760000   0.000000   0.760000 (  0.767154)
 dci_with_extend  1.130000   0.000000   1.130000 (  1.135473)
dci_with_binding  1.000000   0.000000   1.000000 (  0.998439)
=end