1. OMG Issue

UML14 — MOF rules should disallow certain composition relationships

  • Key: UML14-49
  • Legacy Issue Number: 3735
  • Status: closed  
  • Source: Anonymous
  • Summary:

    MOF rules should disallow composition relationships in instance metamodels
    where the container is in one MOF Package and the contained item is in
    another MOF Package and a dependency of the first package on the second is
    not allowed by the physical version of the metamodel due to MOF-imposed IDL
    generation rules.

    Reason for the issue:

    In the process of implementing an XMI-based interchange for UML 1.3, I have
    encountered a serious problem.

    This problem has to do with a divergence between the "Logical" and
    "Physical" model for UML 1.3 caused by rules imposed by MOF.

    In particular, in section 5.5 of the MOF 1.3 specification (27 Sep 99
    version), "Preconditions for IDL Generation", requires that there be no
    cyclical dependencies between ModelElements in a meta-model.

    However, the UML 1.3 specification (June 1999) has a cyclical dependency
    between the Core and the Extension Mechanisms packages in the metamodel (See
    Figure 2-4). This cyclical dependency is explicitly disallowed by the
    precondition cited above.

    This circular dependency was removed from the "Physical Model" for UML 1.3
    in order to allow CORBA IDL and XMI DTD declarations in conformance with the
    precondition. As a result of the removal of this dependency, there are
    tremendous difficulties expressing the composition relationship between the
    UML ModelElement and the UML Tagged Value (see figure 2-10). In fact, the
    TaggedValue XML elements cannot even be in the exported UML Package element
    – they must be placed outside of it. This greatly complicates the export
    and import of UML 1.3 model files.

  • Reported: UML 1.3 — Fri, 30 Jun 2000 04:00 GMT
  • Disposition: Resolved — UML 1.4.2
  • Disposition Summary:

    No Data Available

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