Modeling and Checking for Non-functional Attributes in Extended UML Class Diagram

A model is a blueprint of a system, which influences the quality of the system. A high quality model should specify not only the functional attributes of a system, i.e., what the system can do, but also the non-functional attributes, i.e., how well the system can do. Modeling for non-functional attributes, especially, the integration of nonfunctional attributes description with functional description and the checking for non-functional attributes, are rarely taken into account by the de facto modeling approaches and tools, while they support modeling and checking for the functional attributes well. In this paper, we extend UML class diagram by adding two model elements, i.e., the nonfunctional attributes notation and the constraint relationships table, for modeling non-functional attributes. An approach is given for checking consistency and satisfiability of the non-functional attributes in the extended UML class diagram. We use an example to demonstrate our proposal.