code: def add_defaults_local
        super
        self.capacity ||= Capacity.new.add_defaults
        self.row_label ||= capacity.rows && capacity.rows > 0 ? 'Row' : 'Unused'
        self.column_label ||= capacity.columns && capacity.columns > 0 ? 'Column' : 'Unused'
      end
docs: Adds an empty capacity and default dimension labels, if necessary.
   The default +one_dimension_label+ is 'Column' if there is a non-zero dimension capacity, 'Unused' otherwise.
   The default +two_dimension_label+ is 'Row' if there is a non-zero dimension capacity, 'Unused' otherwise.
  
   @quirk JRuby See {#merge_container_type_attributes}. Work-around is that each ContainerType
     subclass must alias +add_defaults_local+ to this method.