Calculating and Modeling Common Parts of Software Product Lines

This paper builds on product line CCS (PL-CCS), an algebraic approach to modeling the behavior of software product lines. The semantics of PL-CCS specifications is given in terms of labeled transition systems for individual products as well as for the entire product line and can be derived automatically. In this paper, we extend PL-CCS with a concept for specifying dependencies, show how to integrate it into a development methodology for product lines and validate its practical applicability by modeling a typical reactive system from the automotive domain. Most importantly, due to the algebraic nature of our model, we can derive calculation laws that allow to compute common parts of a product line. The application of the corresponding calculation rules is illustrated in detail with an example. By this, we obtain a formal foundation for restructuring product lines.