gistfile1.rb

# Include in classes that have an Address
# Adds shortcut getter/setter methods for line1, line2, city, state, zip.
module AddressDelegation
  extend ActiveSupport::Concern

  included do
    include InstanceMethods
    def assign_attributes_with_delegation attributes, options
      setup_address
      delegate_address_attributes
      assign_attributes_without_delegation attributes, options
    end

    alias_method_chain :assign_attributes, :delegation
    after_initialize :setup_address
    after_initialize :delegate_address_attributes
  end

  module InstanceMethods

    protected
    def _address_reflection
      @_address_reflection ||= reflections.keys.detect{|k| k.to_s =~ /address/ }
    end

    def _address
      @_address
    end

    def delegate_address_attributes
      [ "state", "city", "zip", "line1", "line2" ].each do |col|
        self.class.delegate :"#{col}", :"#{col}=", :to => :_address
      end
    end

    def setup_address
      instance = nil
      if _address_reflection
        instance = (new_record? && send(_address_reflection).nil?) ? send(:"build_#{_address_reflection}") : send(_address_reflection)
        puts instance
      end
      self.instance_variable_set("@_address", instance)
    end
  end
end