A Foundational Service Framework

Abstract

Despite the proliferation of Web services, the field of service research is still in its infancy, where there has been little foundational work to date. In this chapter, we present the foundational service framework that helps address some fundamental research issues on Web services [44, 74]. The presented framework offers a systematic approach that enables users to achieve an op- timal Service Execution Plan (SEP) by submitting declarative service queries. Figure 3.1 shows the overall architecture of the service query optimization framework. At the bottom, we have the service space for a given application domain that consists of the actual service providers, a.k.a., service instances. The integration layer helps resolve the discrepancy of the service schemas and provides a uniformed view of the service space. It can achieve this by ap- plying the existing data integration techniques [40], which are not the focus of this work. The QoWS manager deals with the collection of quality related information from the service instances. The quality data will be used by the query optimizer to make selection from the competing service providers. The service model captures a set of key features of Web services that lay out a foundation for service query specification, processing, and optimization. The service calculus enables users to use declarative service queries to locate Web services, which is more precise and reliable than the keyword based search. The query processor generates SEPs which can be used by the users to invoke services.