Xcd - Modular, Realizable Software Architectures

Connector-Centric Design (XCD) is centred around a new formal architectural description language, focusing mainly on complex connectors. Inspired by Wright and BIP, XCD aims to cleanly separate in a modular manner the high-level functional, interaction, and control system behaviours. This can aid in both increasing the understandability of architectural specifications and the reusability of components and connectors themselves. Through the independent specification of control behaviours, XCD allows designers to experiment more easily with different design decisions early on, without having to modify the functional behaviour specifications (components) or the interaction ones (connectors). At the same time XCD attempts to ease the architectural specification by following (and extending) a Design-by-Contract approach, which is more familiar to software developers than process algebras like CSP or languages like BIP that are closer to synchronous/hardware specification languages. XCD extends Designby-Contract (i) by separating component contracts into functional and interaction sub-contracts, and (ii) by allowing service consumers to specify their own contractual clauses. XCD connector specifications are completely decentralized, foregoing Wright’s connector glue, to ensure their realizability by construction.