Abstract:

Analyzing traditional definitions of NonFunctional Requirements (NFR), this paper redefined NFR as constraints on 'requirements model' that is an available system abstraction at requirements analysis stage. The proposed definition formulates the relationships among NFR and functional requirements. Furthermore, this paper extended a traditional featureoriented software product line requirements modeling approach to explicitly model NFR, functional requirements, the type of NFR, as well as various relationships among them, and to model NFRs variability in the same way of modeling variability in traditional feature model. The proposed approach enables explicitly compilation and customization of NFRrelated assets across projects, and is a solid basis for quantitative evaluation on the quality of the derived products. Furthermore, we presented a multipleview based and featureoriented approach to guide developers to iteratively model both NFR and functional requirements, and meantime to achieve goals including separation of concerns and model complexity management. Finally, a tool prototype was implemented and a case study was conducted.

Key words: nonfunctional requirements;software product line;feature model;multiple views