module,extend,composed_of,advanced-activerecord

http://giantrobots.thoughtbot.com/2008/6/2/slides-from-railsconf
http://api.rubyonrails.org/classes/ActiveRecord/Aggregations/ClassMethods.html#M001663
http://www.ruby-doc.org/core/classes/Object.html#M000337

有類似的class method, validates, 就把他弄進module 裡

<br />class User < ActiveRecord::Base<br /> has_address :shipping<br /> has_address :billing #傳參數進去 生成其他的method<br /><br /> has_many :orders<br />end<br />
<br />module Addressable<br /> class << self #include 需要是class method<br /> def included(base)<br /> base.extend ClassMethods #extend 進來的method, 是上面User的class methods<br /> end<br /> end<br /> module ClassMethods<br /> def has_address(name)<br /> name << “_” unless name.blank?<br /> validates_presence_of "#{name}address_one", "#{name}city",<br /> "#{name}state_province", "#{name}postal_code", "#{name}country"<br /> validates_format_of "#{name}postal_code", :with => /\d{5}(-\d{4})?/,<br /> :if => Proc.new { |user| user["#{name}country"] == "US" }<br /> validates_format_of "#{name}postal_code", :with => /[a-zA-Z]\d[a-zA-Z] \d[a-zA-Z]\d/,<br /> :if => Proc.new { |user| user["#{name}country"] == "CA" }<br /> composed_of "#{name}address", :class_name => “Address<br /> :mapping => [ ["#{name}address_one", "address_one"],<br /> ["#{name}address_two", "address_two"],<br /> ["#{name}city", "city"],<br /> ["#{name}state_province", "state_province"],<br /> ["#{name}postal_code", "postal_code"]<br /> ["#{name}country", "country"] ]<br /> end<br /> end<br />end<br />
<br /> ActiveRecord::Base.send :include, Addressable<br />