Alfa: A framework for composing software architectures from architectural primitives

Architectural styles represent composition patterns and constraints at the software architectural level and are targeted at families of systems with shared characteristics. They enable architectural reuse and hence can bring economy to architecture-based software development. Existing research on architectural styles provides little guidance for the systematic design and construction of architectural style elements. This paper proposes a framework, Alfa, for systematically and constructively composing “architectural primitives” to obtain elements of architectural styles. This is based on our observation that architectural styles and, indeed, software architectures share many underlying concepts that lead to architectural primitives. We have identified eight forms and nine functions as architectural primitives that reflect the syntactic and semantic characteristics of software architectures and are expressive enough to compose elements of architectural styles used in modern, distributed systems. Such an approach enables systematic construction of style-based architectures. In that direction, this paper evaluates the suitability of Alfa as an assembly language for software architectures and its suitability for composing architectural styles for network-based systems.