Rails Associations - Cascading Update

Question

I have multiple classes with many associations linking them together and I would like to be able to take the top-level object, close it, and have all of the child-objects closed as well. I need each object to be closed because I want to be able to pick any parent and have all of it's children closed.

For example (I realize this probably doesn't exist):

class Requisition
  has_many :shipments, :dependent_method => :close
end

class Shipment
  belongs_to :requisition

  has_many :reroutes, :dependent_method => :close
end

class Reroute
  belongs_to :shipment

  has_many :deliveries, :dependent_method => :close
end

class Delivery
  belongs_to :reroute
end

Does anybody know of a good solution to achieve this? A gem/plugin would be perfectly acceptable :-)

Thanks much!

Answer 1

Its hard to understand your goal. It would help if you could clarify what you mean by "close".

The following information may answer your question.

ActiveRecord has the concept of persistence to the database through the 'save' and 'save!' methods. By default, association objects are saved when a parent object is saved.

Answer 2

if you never actually delete a row from your DB using the destroy methods you could just overwrite destory methods to do the dateClosed and then i believe :dependent => :destroy just calls the related objects destroy method

def destroy
   dateClosed = Date.today
end

class Requisition  has_many :shipments, :dependent => :destroy

Answer 3

I sat down and wrote a little plugin to do this. I call it acts_as_closable and it simply adds the following method to a before_save filter. You have to use the :autosave => true for each association that you want this to work with, but that made sense to me rather than having acts_as_closable automatically save the association for you. I may make it an option later and release the code. Here is the meat:

def update_closed_status_of_children
  [self.class.reflect_on_all_associations(:has_many), self.class.reflect_on_all_associations(:has_one)].flatten.each do |assoc|

    # Don't consider :through associations since those should be handled in
    # the associated class
    if not (assoc.options.include? :through)
      attribute = self.class.acts_as_closable_config.closed_attribute
      children = self.send(assoc.name)
      children = Array(children).flatten.compact

      children.each do |child|
        # Check to make sure we're only doing this on something declaring acts_as_closable
        if child.class.included_modules.include? ActsAsClosable
          child.send(:closed_value=, self.closed_value)
        end
      end
    end

  end
end

I define some other methods (like :closed_value= and :closed?) but this is the main code I had to figure out. Hope it helps someone else!