one_key_proxy.rb

require 'ripple/associations/proxy'
require 'ripple/associations/one'

module Ripple
  module Associations
    class OneKeyProxy < Proxy
      include One

      def replace(doc)
        @reflection.verify_type!(doc, owner)
        doc.key = owner.key
        
        owner.class.__send__(:define_method, "key=") do |value|
          doc.key = value unless doc.key == value
          super(value) unless key == value
        end

        loaded
        @target = doc
      end

      def find_target
        klass.find(owner.key)
      end

      protected
      def instantiate_target(instantiator, attrs={})
        @target = super
        @target.key = owner.key
        @target
      end

    end
  end
end