Web Service Contracts: Specification and Matchmaking

Web services promise universal interoperability through integration of services developed by independent providers. The coming of the Cloud Computing paradigm extends the need to share resources (e.g., platform, infrastructure, data) that are accessible as Web services. This means that a key factor to build complex and valuable business processes among cooperating organizations relies on the efficiency of automate the discovering of appropriate Web services. The increasing availability of Web services that offer similar functionalities requires mechanisms to go beyond the pure functional discovery. This chapter proposes the evaluation of Web service contracts, which define non-functional properties (NFPs) and applicability conditions associated with Web services, as a solution to automate process composition and enactment. Today, there is a lack of tools and algorithms that fully support this solution due to several open issues. First, existing languages don't provide the right constructs for the specification of Web service contracts. Second, the lack of standard languages determines heterogeneity in Web service contract specifications raising interoperability issues. Third, Web service contract evaluation is only partially supported by existing discovery engines and composition tools when combining different services from different providers. This chapter proposes some research efforts on addressing these open issues.