Understanding and Propagating Architecutural Changes

Like source code, architectures change. The use of product line architectures provides a particularly rich source of changes: new products are introduced, existing products are enhanced and modified, and old products are retired. Methods exist that record these kinds of changes by maintaining explicit representations of the evolution of a product line architecture. Despite the availability of such representations, it still is difficult to quickly gain an understanding of the exact changes that define the difference between two products. Furthermore, it is difficult to automatically propagate such changes to yet another, third product in the product line. This paper aims to fill this void and contributes a set of algorithms and an associated representation for understanding and propagating architectural changes within a product line architecture. The approach is based on xADL 2.0, an extensible representation for product line architectures, and adapts well-known differencing and merging algorithms from the field of configuration management to the domain of software architecture.