Checking UML Model Consistency

UML is nowadays a de-facto standard for design and development of (object-oriented) software. With version 2.0 UML has achieved a more precise formal semantics. The same happened to OCL, a specification language which is an integral part of UML that allows to embed software contracts in the model. In this work we propose an approach for a static verification of consistency of UML models which relies on OCL constraints. Many approaches for model validation and verification rely on generation of suitable code which dynamically (i.e., at run-time) checks the validity of OCL constraints. This approach has several drawbacks. For example, it cannot generally guarantee that a constraint will never be violated, unless an infinite number of tests is performed. Also the generation of just a significative finite subset is not so feasible because, on one hand, a considerable manual effort is needed even to produce a single test scenario and, on the other hand, test-case generation is well-known to be a hard