Extending UML templates towards flexibility (extended version)

Abstract

UML templates are generic model elements that may be instantiated as domain specific solutions by means of parameterization. Some of the elements in a tem-plate definition are marked as parameters, which must be substituted by conform-ing elements in the domain model to get a fully functional instance of the tem-plate. The validation of parameter substitutions enforces that the parametered ele-ment and its substitute must be of the same kind (both classes, both attributes, etc.). This paper shows that such imperative restrains the applicability of tem-plates and proposes an alternative set of constraints that, by allowing substitu-tions among elements of different kinds, widens that applicability. Cross-kind substitutions, however, require adequate semantics for the Binding relationship. Such semantics are proposed as model transformations that must complement the plain substitutions preconized by UML and are exemplified w.r.t. the instantiation of activity diagrams.