def minimal_match?(other)
      self.class === other and
        (identifier.nil? or other.identifier.nil? or identifier == other.identifier)
    end
def minimal_match?(other)
      self.class === other and
        (identifier.nil? or other.identifier.nil? or identifier == other.identifier)
    end
Returns the domain object in others which matches this dependent domain object
 within the scope of a parent on a minimally acceptable constraint. This method
 is used when this object might be partially complete--say, lacking a secondary key
 value--but is expected to match one of the others, e.g. when matching a referenced
 object to its fetched counterpart.

 This base implementation returns whether the following conditions hold:
 1. other is the same class as this domain object
 2. if both identifiers are non-nil, then they are equal

 Subclasses can override this method to impose additional minimal consistency constraints.

 @param [Resource] other the domain object to match against
 @return [Boolean] whether this Resource equals other