obeying SRP by using composition

# table 'customers' has columns 'adr_street', 'adr_city', 'adr_zip'
class Customer < ActiveRecord::Base
  composed_of :customer_address,
    :mapping => [['adr_street', 'street'], ['adr_city', 'city'], ['adr_zip','zip']]
end

class CustomerAddress
  attr_reader :street, :city, :zip
  def initialize(street,city,zip) ;  @street,@city,@zip = street,city,zip ; end
  def close_to?(other_address) ; ... ; end
  def ==(other_address) ; ... ; end
end