Modifying an inherited Rails association

Question

I have a Team class that inherits from a Group class. Both Team and Groups have memberships through the same association. However, I need to run a method after a Team memberships is added but not a Group. I currently have something like this:

class Group < ActiveRecord::Base
  has_many :memberships, 
           :class_name => 'Connection',
           :foreign_key => 'connectable_id',
           :as => :connectable,
           :dependent => :destroy
end

class Team < Group
  has_many :memberships, 
           :class_name => 'Connection',
           :foreign_key => 'connectable_id',
           :as => :connectable,
           :dependent => :destroy,
           :after_add => :membership_check

private
   def membership_check(membership)
   end
end

Is there some way to modify the inherited association in Team so that I don't have to redefine the entire thing but rather just add the :after_add hook it?

Any help would be appreciated.

Answer 1

The clearest way I can see is to define add_company_membership in the Group class as an empty method, then override it in Team to actually do what you want there. You then keep the :after_add on Group and go from there.

Unfortunately it's not as clean as just being able to ignore any idea of :after_add in the Group class, which would be ideal.

Answer 2

Have you tried just adding the :after_add hook in only the subclass Team? It won't get called in Group since it's the superclass, right?

Answer 3

Try this and let me know if it works. It should I think. Make sure that your membership_check method is not private anymore.

class Group < ActiveRecord::Base
  has_many :memberships, 
           :class_name => 'Connection',
           :foreign_key => 'connectable_id',
           :as => :connectable,
           :dependent => :destroy,
           :after_add => proc {|gr, dev| gr.membership_check(dev) if gr.respond_to? :membership_check}
end

class Team < Group
  def membership_check(membership)
  end
end

P.S. I'm not sure what you needed to pass into the membership_check argument, but the added developer seems to make sence.

P.P.S If you want to keep membership_check private, you may use gr.send(:membership_check, dev) to bypass the visibility constraint. But I don't see why you should.