Conservative re-use ensuring matches for service selection

The greater and greater quantity of services that are available over the web causes a growing attention to techniques that facilitate their reuse. A web service specification can be quite complex, including various operations and message exchange patterns. In this work, we give a declarative representation of services, and in particular of WSDL operations, that enables the application of techniques for reasoning about actions and change. By means of these techniques it becomes possible to reason on the specification of choreography roles and on possible role players, as a basis for selecting services which match in a flexible way with the specifications. Flexible match is, indeed, fundamental in order to enable web service reuse but it does not guarantee the preservation of the goals, that can be proved over the role specification itself. We show how to enrich various kinds of match proposed in the literature so to produce substitutions that preserve goals.