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In this paper we discuss an effective technique for automatic service composition and we present the prototype software that implements it. In particular, we characterize the behavior of a service in terms of a finite state machine. In this setting we discuss a technique based on satisfiability in a variant of Propositional Dynamic Logic that solves the automatic composition problem. Specifically, given a client specification of his desired service, i.e., the service he would like to interact with, and a set of available services, our technique synthesizes the orchestration schema of a composite service that uses only the available services and fully realizes the client specification. The developed system is an open-source software tool, called (e-service composer), that implements our composition technique starting from services, each of them described in terms of a WSDL specification and a behavioral description expressed in any language that can capture finite state machines. [ABSTRACT FROM AUTHOR]

Whether two web services are compatible depends not only on static properties like the correct typing of their message parameters, but also on their dynamic behaviour. Providing a simple description of the service behaviour based on process-algebraic or automata-based formalisms can help detecting many subtle incompatibilities in their interaction. Moreover, this compatibility checking can to a large extent be automated if we define the notion of compatibility in a sufficiently formal way. Based on a simple behavioural representation, we survey, propose and compare a number of formal definitions of the compatibility notion, and we illustrate them on simple examples. [ABSTRACT FROM AUTHOR]

In [3] we started studying an advanced form of service composition where available services were modeled as deterministic finite transition systems, describing the possible conversations they can have with clients, and where the client request was itself expressed as a (virtual) service making use of the same alphabet of actions. In [4] we extended our studies by considering the case in which the client request was loosen by allowing don't care nondeterminism in expressing the required target service. In the present paper we complete such a line of investigation, by considering the case in which the available services are only partially controllable and must be modeled as nondeterministic finite transition systems, possibly because of our lack of information on their exact behavior. Notably such services display a "devilish" form of nondeterminism, since we want to model the inability of the orchestrator to actually choose between different executions of the same action. We investigate how to automatically perform the synthesis of the composition under these circumstances. [ABSTRACT FROM AUTHOR]