Alexandre Martins’ Blog

Currently I’m working on my personal project, aiming to increase my Ruby On Rails skills. It’s quite a simple system for my dad’s company and one of the features is to register his clients. I started it out writing the Specs and as I’m new to the Ruby world, doubts started to pop inside my head. I was wondering how to use Value Objects ( Eric Evans definition, please! ) integrated with RoR, something I can do with Java as shown below:

public class Phone() {
    private int code;
    private int number;
    ....
}

public class Client() {
    private String name;
    private Phone home;
    private Phone mobile;
    ....
}

Chatting with Carlos Villela, he advised me to take a look at composed_of feature, that it would help me get the solution for my problem. The final result is shown below. I’m definitely not used to the Ruby syntax yet, for me it’s still a bit confusing.

class Phone
  attr_reader :code, :number
  def initialize(code, number)
      @code, @number = code, number
  end

  def ==(other)
      code==other.code && number==other.number
  end
end

class Client < ActiveRecord::Base
  composed_of :home, :class_name => "Phone",
        :mapping => [ %w(home_code code), %w(home_number number) ]
  composed_of :mobile, :class_name => "Phone",
        :mapping => [ %w(mob_code code), %w(mob_number number) ]
end