Seamless Formalizing the UML Semantics through Metamodels

Despite the fact that the Unified Modeling Language (UML) has been adopted by the Object Management Group (OMG2 ) as the standard notation for use in Object-Oriented (OO) Systems Development, it still does not have a truly formal semantics. There is currently much effort directed towards formalizing particular aspects or models of UML. However, the literature gives little insight into the appropriate strategy for tackling this problem within an integrated basis including the language evolution. This chapter identifies and discusses three feasible strategies which can be applied to formalize UML. One of these strategies is selected to underpin the four-layer architecture on which UML is based. The approach is based on the soundness of algebraic specification theory, which, in addition, provides suitable theorem-proving capabilities for exploiting the UML formal model obtained. The formal models proposed are specified using an executable algebraic specification language called Maude.