SPEM — Standardization

Standardization

SPEM is a MOF-based metamodel (p 1-2) which is defined as an extension of a
subset of UML (SPEM foundation; p 1-3). However, SPEM cannot be considered
as a conservative extension of the UML metamodel since the SPEM foundation
does not keep the semantics of the UML meta-model (i.e., some elements of
the SPEM foundation have not the same structure, associations, an-cestors
and, hence, semantics as their counterparts in the UML metamodel).
This lack of conformance with UML compromises standardization. In
particular, the SPEM foundation elements cannot rely on the semantics of the
UML metamodel. As a result, the semantics of the SPEM UML-profile are not
well-defined and the portability of SPEM models is impaired.

• Example 1: A UML metamodel Association, as a GeneralizableElement,
  inherits several at-tributes (e.g., isRoot, isLeaf). A SPEM Association does
  not inherit them (since it is not a Gen-eralizableElement). A UML tool may
  require a value for those attributes in Association in-stances.
• Example 2: The UML metamodel defines several constraints on Package
  regarding the asso-ciation importedElement. Since this association is not
  defined in SPEM, those constraints make no sense.

Proposed resolution:
1. Keep UML metamodel ancestors for all the SPEM foundation elements.
2. Keep UML metamodel associations involving SPEM foundation elements (this
includes asso-ciations with elements not belonging to SPEM foundation)
3. Incorporate constraints restricting the semantics of the UML metaelements
in a SPEM model (e.g., Add to Package, the constraint:
self.importedElement->size=0)

reject, see above