1. OMG Issue

UML14 — Notation for inherited associations

  • Key: UML14-48
  • Legacy Issue Number: 3682
  • Status: closed  
  • Source: David Frankel Consulting ( David Frankel)
  • Summary:

    The CWM submitters needed to display inherited associations on some class
    diagrams to enhance understandability. These were not intended to be
    derived associations; that is, there was no intention to specify additional
    computational machinery when showing these inherited associations.
    Unfortunately, the MOF and UML have no succint way to display inherited
    associations. The CWM submitters placed the "/" derived prefix on the
    association end names in the class diagrams. At the same time, in order to
    prevent the generation of additional computational machinery, they omitted
    the inherited association from the normative XMI rendition of the metamodel.
    This was probably a reasonable choice under the circumstances. However, it
    means that the class diagrams and the XMI representation of the metamodel
    conflict with one another.

    It is very common to need to show inherited associations on a class diagram.
    We ran into this when we specified the CORBA metamodel for the CORBA
    Component Model submission. We used derived associations in the class
    diagrams as well. However, we retained the derived associations in the XMI
    rendition of the metamodel. In order to prevent additional computational
    machinery from being generated, we stereotyped the associations as
    <<implicit>>. This stereotype is defined in the UML specification but not
    in the MOF specification and says that an association is only conceptual and
    not manifest. We then made sure that the generator producing the IDL and
    XML DTDs was sensitive to the <<implicit>> stereotype. This had the
    advantage of maintaining consistency between the class diagrams and the XMI
    rendition of the metamodel. Of course this is also a non-standard
    approach--since <<implicit>> is not defined in the MOF, we can't expect MOF
    generators to understand it.

    The lack of a standard means for representing inherited associations in
    class diagrams is thus resulting in a proliferation of non-standard
    approaches in adopted OMG metamodels. This could become unmanageable as the
    number of metamodels grows. A standard means should be specified.

  • Reported: UML 1.3 — Mon, 3 Jul 2000 04:00 GMT
  • Disposition: Resolved — UML 1.4.2
  • Disposition Summary:

    No Data Available

  • Updated: Fri, 6 Mar 2015 20:58 GMT