Module: ActiveZuora::BelongsToAssociations::ClassMethods

Defined in:
lib/active_zuora/belongs_to_associations.rb

Instance Method Summary collapse

Instance Method Details

#belongs_to(item, options = {}) ⇒ Object


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# File 'lib/active_zuora/belongs_to_associations.rb', line 8

def belongs_to(item, options={})
  class_name = options[:class_name] || nested_class_name(item.to_s.camelize)
  foreign_key = options[:foreign_key] || :"#{item}_id"
  # Add the field if it doesn't already exist.
  field foreign_key, :string unless field? foreign_key
  ivar = "@#{item}"
  loaded_ivar = "@#{item}_loaded"
  # Define the methods on an included module, so we can override
  # them using super.
  generated_attribute_methods.module_eval do
    define_method(item) do
      # Return the object if it was already loaded.
      if instance_variable_get(loaded_ivar)
        return instance_variable_get(ivar)
      else
        # Otherwise find it.
        record = class_name.constantize.find self.send(foreign_key)
        send("#{item}=", record)
        record
      end
    end
    define_method("#{item}=") do |record|
      instance_variable_set(loaded_ivar, true)
      instance_variable_set(ivar, record)
      # Set the foreign key id attribute as well.
      write_attribute(foreign_key, record.try(:id))
      record          
    end
    redefine_method("#{foreign_key}=") do |item_id|
      item_id = write_attribute(foreign_key, item_id)
      # Unload the object if the id is different.
      if send("#{item}_loaded?") && send(item).id != item_id
        instance_variable_set(loaded_ivar, false)
      end
      item_id
    end
    define_method("#{item}_loaded?") do
      instance_variable_get(loaded_ivar) || false
    end
    define_method("reload_#{item}") do
      instance_variable_set(loaded_ivar, false)
      send(item)
    end
  end
end