Adopting computational independent models for derivation of architectural requirements of software product lines

The alignment of the software architecture and the functional requirements of a system is a demanding task because of the difficulty in tracing design elements to requirements. The 4SRS (Four Step Rule Set) is a UML based model driven method for single system development which provides support to the software architect in this task. This paper presents an evolution of the 4SRS method aimed at product lines. In particular, we describe how to address the transformation of functional requirements (use cases) into component based requirements for the product line architecture. In order to achieve this, we have extended the 4SRS method to explicitly handle variability. This evolution of 4SRS is based on an extension of the UML-F profile proposed by the authors. The UML-F profile provides UML notational extensions required to model variability. We present our approach in a practical way and illustrate it with an example.