DCI and Aggregate

dci_and_aggregate.rb

class Human
  attr_accessor :address
end

class Address
  def to_s
    "City: #{@city}"
  end
 
  private

  def initialize(city)
    @city = city
  end
end

module Policeman
  def check_address(address)
    # do some stuff
  end
end

module Thief
end

module FakeAddress
  def to_s
    "City: LA"
  end
end

class ArrestContext
  def execute
    @policeman.check_address @thief.address.to_s
  end

  private
  
  def initialize(policeman, thief)
    @policeman = policeman
    @policeman.extend Policeman

    @thief = thief
    @thief.extend Thief
    @thief.address.extend FakeAddress
  end
end

policeman, thief = Human.new, Human.new
thief.address = Address.new 'NY'

context = ArrestContext.new policeman, thief
context.execute

http://andrzejonsoftware.blogspot.com/2011/08/dci-patterns-how-to-write-dci-contexts.html