Abstract:
Stereotypes were introduced into the UML in order to offer extensibility
to the basic metamodel structure by the user and without actually modifying
the metamodel. In UML version Lx, this was accomplished by means of
permitting virtual subtyping in the metamodel. However, this facility led many
to misuse stereotypes, particularly in places where regular domain-level modelling
would be more appropriate. In version 2.0 of the UML, the portion of the
metamodel pertaining to stereotypes was drastically revised. The resulting
mechanism is reviewed here and compared with that of version l.x. From a set
theory point of view, the new (2.0) metamodel is unfortunately untenable and
the examples used in the OMG documentation unconvincing. This paper outlines
the issues and suggests some possible steps to improve the UML 2.0
stereotypetheory and practice.
