Supporting evolutionary development by feature models and traceability links

During their usage, software systems have to be changed constantly. If such changes are implemented in an incomplete or inconsistent way a loss of architectural quality will occur, i.e. in terms of maintainability and understandability. The lack of traceability of the impact of changed requirements in the software enhances this effect. Traceability links have been proposed as a link between the requirements and the different parts of a solution. In practical use, these links are difficult to establish and maintain. Currently, tools cannot effectively support these links due to human-required decisions. This paper introduces feature models as an intermediate element for linking requirements to design models. They enable a more appropriate bridging of the different levels of abstraction. Feature models group sets of requirements to a feature and enable a modeling of the variability of requirements. The feature models structure traceability links between requirements, design elements and implementation parts. This leads to lower efforts of establishing and maintaining the links. Furthermore, descriptions of design decisions can be attached to the links. Industrial experience with this approach shows its support for the evolutionary development of large software systems, especially in the improved comprehension of the changes by the developers.