在哪裏把我的紅寶石課堂類「元生成器」？

Question

我有以下幾點：

class ThirdParty < ActiveRecord::Base 
    # Dynamically adds accessors of the requested kind. 
    def self.has_many_children_of_kind (kinds=[]) 
    puts 'In generator method' 
    kinds.each { |k| 
     n   = k.to_s 
     self.class_eval %{ 
     has_many :#{n}_as_owner, { 
         :foreign_key => :owner_id, 
         :class_name => 'ThirdPartiesLink', 
         :conditions => #{ k!=:third_parties ? "{ :kind => '"+n.singularize+"' }" : 'nil' } 
        } 
     has_many :#{n}, { 
         :through  => :#{n}_as_owner, 
         :source  => :owned 
        } 
     } 
     } 
    end 
    # Make dynamic associations of given kinds. 
    has_many_children_of_kind [ :third_parties, :customers, :suppliers, :contacts ] 
end 
class ThirdPartiesLink < ActiveRecord::Base 
    belongs_to :owner, :foreign_key => :owner_id, :class_name => 'ThirdParty' 
    belongs_to :owned, :foreign_key => :owned_id, :class_name => 'ThirdParty' 
    # This model has a column named 'kind' for storing the link kind. 
end 

一切工作完全按照我的期望。 線：

has_many_children_of_kind [ :third_parties, :customers, :suppliers, :contacts ] 

生成：

has_many :third_parties_as_owner, { :foreign_key => :owner_id, :class_name => 'ThirdPartiesLink', :conditions => nil } 
has_many :third_parties, { :through => :third_parties_as_owner, :source => :owned } 
has_many :customers_as_owner, { :foreign_key => :owner_id, :class_name => 'ThirdPartiesLink', :conditions => { :kind => 'customer' } } 
has_many :customers, { :through => :customers_as_owner, :source => :owned } 
has_many :suppliers_as_owner, { :foreign_key => :owner_id, :class_name => 'ThirdPartiesLink', :conditions => { :kind => 'supplier' } } 
has_many :suppliers, { :through => :suppliers_as_owner, :source => :owned } 
has_many :contacts_as_owner, { :foreign_key => :owner_id, :class_name => 'ThirdPartiesLink', :conditions => { :kind => 'contact' } } 
has_many :contacts, { :through => :contacts_as_owner, :source => :owned } 

然而，每次我刷新，其中第三方對象使用的，「線發生器方法」在控制檯被outputed的頁面。

我已經試過幾件事情： puting的has_many_children_of_kind在我的應用程序的初始化，而不是把它在第三方類的（我真的不喜歡的是，它更多的是測試比什麼都重要的）。在這種情況下，頁面的第一個顯示器在服務器重新啓動後工作，但如果我刷新頁面，在ThirdParty實例上調用時未找到生成的方法...

什麼是確保ThirdParty類在服務器啓動時一次全部使用訪問器寫入？

謝謝你的時間！ Pierre。

編輯：發電機方法塊也可以是這樣的：

kinds.each { |k| 
    n   = k.to_s 
has_many("#{n}_as_owner".to_sym, { 
     :foreign_key => :owner_id, 
     :class_name => 'ThirdPartiesLink', 
     :conditions => (k!=:third_parties ? { :kind => n.singularize } : nil) 
    } 
) 
has_many(n.to_sym, { 
     :through  => "#{n}_as_owner".to_sym, 
     :source  => :owned 
    } 
) 
} 

什麼是最好的？評估還是最新？我會說最新的，因爲沒有涉及解析器/評估，所以它可能會更快一點，對吧？

Answer 1

MikeOnRails指出了一個很好的答案。