Executable connectors: towards reusable design elements

The decomposition of a software application into components and connectors at the design stage has been promoted as a way to describe and reason about complex software architectures. There is, however, surprisingly little language support for this decomposition at implementation level. Interaction relationships which are identified at design time are lost as they get spread out into the participating entities at implementation. In this paper, we propose first-class connectors in an object-oriented language as a first step towards making software architecture more explicit at implementation level. Our connectors are run-time entities which control the interaction of components and can express a rich repertoire of interaction relationships. We show how connectors can be reused and how they enhance the reuse of components.