Effective modeling of software architectural assemblies using constraint automata

Alfa is a framework for the construction of software architectures and their elements from architectural primitives. In any system involving events from multiple sources, synchrony and asynchrony between events arise naturally. Support for simultaneous synchrony and asynchrony, and scalability to assemblies of large numbers of architectural primitives are central concerns for effectively modeling software architectural assemblies in Alfa. An increasingly popular formalism for event-based modeling of the behavior of software architectures, labeled transition systems (LTS), was initially chosen to model the behavior of Alfa assemblies. However, this creates an impedance mismatch with the architect's mental model and lacks sufficient scalability. We therefore propose a formal approach to effectively model software architectural assemblies that addresses these limitations, using constraint automata. Constraint automata can be mapped to LTS thus utilizing existing techniques for analysis of behavioral properties. We evaluate the effectiveness of our approach using two application architectures assembled from Alfa's primitives.