A Precise Approach to Validating UML Models and OCL Constraints

Abstract

The Unified Modeling Language (UML) is a widely accepted standard for modeling software systems. The UML supports object-oriented approaches to software development with a rich set of modeling concepts. The graphical notation of UML includes diagrams such as use case diagrams, class diagrams, state diagrams and sequence diagrams. These are used for describing static as well as dynamic aspects of a system. An important part of UML is the Object Constraint Language (OCL) – a textual language that allows to specify additional constraints on models in a more precise and concise way than it is possible to do with diagrams only. While UML offers a rich set of concepts and diagrams, it is still an unsolved problem what the precise meaning of a model and associated constraints is. A number of problems related to under-specified constructs, ambiguities and contradictions have already been identified in the past. In our view, it is important to have a precise semantics of UML models and OCL constraints. Precise foundations