Rails 1.0 - 使用composed_of 给我错误的参数数量（1 for 5）错误

Question

我正在开发一个 Rails 1.0 应用程序（我无法升级，这是一个奇怪的情况），我尝试使用 :composed_of 功能。我有一个名为 StreetAddress: 的类

class StreetAddress
  attr_reader :address, :address2, :city, :state_id, :zip_code

  def initialize(address, address2, city, state_id, zip_code)
    @address = address
    @address2 = address2
    @city = city
    @state_id = state_id
    @zip_code = zip_code
  end


end 

和一个名为 Hotel 的模型类，

class Hotel < ActiveRecord::Base
  composed_of :street_address
  # ...

end

其中包含 columns:

"id", "brand_id", "code", "location_name", "address", "address2", "city", "state_id", "zip_code", "phone_number", "phone_ext", "fax_number", "time_zone", "url", "room_service_email", "manager_name", "manager_email"

但是，当我尝试访问聚合时，出现错误：

>> h = Hotel.find(1)
=> #<Hotel:0x38ad718 @attributes={"fax_number"=>"1-623-420-0124", "city"=>"Twin
Falls", "address2"=>"285", "brand_id"=>"1", "code"=>"XZWUXUSZ", "manager_email"=
>"[email protected]", "url"=>"http://www.xycdkzolukfvu.hom", "ph
one_number"=>"1-805-706-9995", "zip_code"=>"72436", "phone_ext"=>"48060", "id"=>
"1", "manager_name"=>"Igor Mcdowell", "room_service_email"=>"Duis.risus@Donecvit
ae.ca", "time_zone"=>"America/Boise", "state_id"=>"15", "address"=>"P.O. Box 457
, 7405 Dignissim Avenue", "location_name"=>"penatibus et magnis"}>
>> h.street_address
ArgumentError: wrong number of arguments (1 for 5)
    from (eval):3:in `initialize'
    from (eval):3:in `new'
    from (eval):3:in `street_address'
    from (irb):6

为什么？

Answer 1

composed_of 将尝试使用它所知道的字段来调用对象的构造函数。在您的情况下，它仅发送 street_address 属性（该属性似乎不存在，因此可能为零）。确保使用映射属性集声明您的composed_of，以便它将发送所有属性。

composed_of :street_address, :mapping => [%w(address address), %w(address2 address2), %w(city city), %w(state_id state_id), %w(zip_code zip_code)