An approach to software product line use case modeling

Organizations developing software intensive defense systems are today faced with a number challenges related to characteristics of both the market place and the system domain: 1. Systems grow ever more complex, consisting of tightly integrated mechanical, electrical/electronic and software components. 2. Systems are often developed in short series; ranging from only a few to a few hundred units. 3. Systems have very long life spans, typically 30 years or longer. 4. Systems are developed with high commonality between different customers; however systems are always customized for specific needs. The goal of the research presented in this thesis is to investigate methods and tools to enable efficient development and maintenance of systems in such a context. The strategy adopted in this work is to utilize the forth system characteristic, high commonality, to achieve this. One approach to software reuse, which could be a potential solution as it enables reuse of common parts but at the same time allow for variations, is known as software product line development. The basic idea of this approach is to use domain knowledge to identify common parts within a family of related products and to separate them from the differences between the products. The commonalties are then used to create a product platform that can be used as a common baseline for all products within such a product family. The main contribution of this licentiate thesis is a product line use case modeling approach tailored towards organizations developing software intensive defense systems. We describe how a common and complete use case model can be developed and maintained for a whole family of products, and how the variations within such a family are modeled using a feature model. Concrete use case models, for particular products within a family, can then be generated by selecting features from a feature model. We furthermore describe extensions to the commercial requirements management tool Telelogic DOORS and the UML modeling tool IBM-Rational Rose to support the proposed approach. The approach was applied and evaluated in an industrial case study in the target domain. Based on the collected case study data we draw the conclusion that the approach performs better than modeling according to the styles and guidelines specified by the IBM-Rational Unified Process (RUP) in the current industrial context. The results however also indicate that for the approach to be successfully applied, stronger configuration management and product planning functions than traditionally found in RUP projects are needed