Towards an integrated graph-based semantics for UML

This paper shows how a central part of the Unified Modeling Language (UML) can be integrated into a single visual semantic model. It discusses UML models composed of class, object, state, sequence and collaboration diagrams and presents an integrated semantics of these models. As formal basis the theoretically well-founded area of graph transformation is employed which supports a visual and rule-based transformation of UML model states. For the translation of a UML model into a graph transformation system the operations in class diagrams and the transitions in state diagrams are associated with graph transformation rules that are then combined into one system in order to obtain a single coherent semantic description. Operation calls in sequence and collaboration diagrams can be associated with applications of graph transformation rules in the constructed graph transformation system so that valid sequence and collaboration diagrams correspond to derivations, i.e., to sequences of graph transformation rule applications. The main aim of this paper is to provide a formal framework that supports visual simulation of integrated UML specifications in which system states and state changes are modeled in a straightforward way.