In this paper we introduce a structural and object-oriented model. We present applications of this model to the checking of some ill-formed classes. We focus on static class diagrams mixing inheritance and composition relations. We consider an approach based on the notion of class usefulness, i.e. finitely generated and with at least one defined value. We show that this allows us to eliminate some wrong class designs or wrong schema designs. We present a general process to check this and a static algorithm which applies to the UML language.
['Jean-Claude Royer']
Checking Class Schema Usefulness