Specific Purpose Model Decoration

decoration.rb

class ResourcePurchase::ResourceDecorators::Base < SimpleDelegator
  def anew
  end
  
  def renew
  end
end

# You could write a router if you want to make this follow
# something of a Factory pattern or do something like

class MembershipEvent
  # This could be abstracted into the Purchasable to
  # _try_ to find a related class
  def resource_purchase_class
    ResourcePurchase::ResourceDecorators::MembershipEvent
  end
  
  # Can also be abstracted
  def resource_purchase_instance
    resource_purchase_class.new(self)
  end
end

resource_purchase.item.resource_purchase_instance.anew