Architecture Descriptions of Software Systems: Complex Connectors vs Realisability

With the advent of software architectures, architectural languages have become an active research area for the specification of software architectures in terms of components & connectors and for some extra capabilities such as formal analysis and code generation. In this paper, the existing architectural languages have been analysed for two important language features - i.e., interaction protocols and realisability. The analysis results show that only a few languages support interaction protocols via their first-class connector elements (also referred to as complex connectors). However, complex connectors of those languages lead to unrealisable specifications due to enabling global constraints which may not be possible for distributed systems. Therefore, practitioners cannot implement the system in the way specified, and any analyses (e.g., performance) made on the unrealisable specifications will all be invalid.