MOF 2.4 RTF Avatar
  1. OMG Issue

MOF24 — Because MOF merges UML, UML as an instance of MOF is ill-formed

  • Key: MOF24-75
  • Legacy Issue Number: 16489
  • Status: closed  
  • Source: Model Driven Solutions ( Steve Cook)
  • Summary:

    In MOF 2.4, Reflection::Element merges UML::Element. Then it is stated that Reflection::Element is an implicit superclass of all metaclasses defined using MOF. Hence UML::Element is a subclass of Reflection::Element which merges UML::Element. Reflection::Element has all of the properties of UML::Element (e.g. ownedComment) and so UML::Element may not validly have these properties.

    The solution is for MOF not to merge any part of UML, because there is no need to do so. MOF should simply refer to UML for its definitions.

  • Reported: MOF 2.0 — Wed, 10 Aug 2011 04:00 GMT
  • Disposition: Resolved — MOF 2.4
  • Disposition Summary:

    The fact that MOF merges UML is actually correct, and requires no changes. The
    important “fine print” detail is that PackageMerge is not inheritance. With
    PackageMerge, matching elements in the mergingPackage and the
    receivingPackage are merged into a single element without changing the position of
    that resulting element in the type hierarchy. This means in case of UML::Element
    versus Reflection::Element that UML::Element is augmented with the reflective
    capabilities defined in Reflection::Element without changing its position in the type
    hierarchy of the UML metamodel. In particular, UML::Element is not a subclass of
    Reflection::Element. If seen in the context of MOF, it remains unchanged the
    superclass of all UML metaclasses, but augmented with the MOF capabilities.
    Since version 2.4, MOF is based on a constrained-down UML metamodel. The only
    way to add the additional capabilities of MOF without altering the type hierarchy is
    PackageMerge, therefore MOF needs to merge UML.
    To provide absolute clarity, the clause describing the Package composition of MOF
    shall be improved.

  • Updated: Mon, 20 Apr 2015 17:34 GMT