Connectors as Designs

The complex interactions that appear in service-oriented computing make coordination a key concern in service-oriented systems. Over the past years, the need for high-confidence coordination mechanisms has intensified as new technologies have appeared for the development of service-oriented applications, making formalization of coordination mechanisms critical. Unifying Theories of Programming (UTP) provide a formal semantic foundation not only for programming languages but also for various expressive specification languages. A key concept in UTP is design: the familiar pre/post-condition pair that describes the contract. In this paper we use UTP to formalize Reo connectors, whereby connectors are interpreted by designs in UTP. This model can be used as a reference document for developing tool support for Reo, such as a test case generator. It can also be used as a semantic foundation for proving properties of connectors, such as equivalence and refinement relations between connectors.