Vers une prise en compte des contraintes en UML grâce à Z

The static and dynamic relationships between the system actors and objects, but also the domain and business constraints must be taken into consideration in order to produce a consistent specification. Actual tools mainly support relationships and forget constraints. It is nevertheless necessary to have tools which enable to express and to validate them. In order to enable the validation of constraints, we propose to exploit the formal language power of reasoning. Our approach is based on the expression of the UML diagram and of its constraints in a formal language. We present here the translation of a subset of the UML class diagram and of its constraints into Z. The formal specifications obtained can be exploited to prove the consistency of the constraint set. But constraints can be taken into consideration efficiently only if tools support them. To facilitate this, we propose a tool which integrates constraints and automates the generation of Z formal specifications. The main point of this tool is that the whole modelling work should be done in the UML environment. The formal specifications are seen only when it is necessary. The tool could be based on an industrial UML modelling environment completed by forms containing the constraints. Key word : UML, constraints, OCL, Z, tool support