SUBMITTED FOR PUBLICATION Evolution styles: foundations and models for software architecture evolution

As new market opportunities, technologies, platforms, and frameworks become available, systems require large-scale and systematic architectural restructuring to accommodate them. Today’s architects have few tools and techniques to help them plan this architecture evolution. In particular, they have little assistance in planning alternative evolution paths, trading off various aspects of the different paths, or knowing best practices for particular domains. In this paper we describe an approach for planning and reasoning about architecture evolution. Our approach focuses on providing architects with the means to model prospective evolution paths and supporting analysis to select among these candidate paths. To demonstrate the usefulness of our approach in practice, we show how it can be applied to an actual architecture evolution. In addition, we present some theoretical results about the expressiveness and tractability of our evolution path specification language.