Web services, policies, and context: concepts and solutions

Abstract

Despite the extensive adoption of Web services by IT system developers, they still lack the capabilities that could enable them to match and eventually surpass the acceptance level of traditional integration middleware (e.g., CORBA, Java RMI). This lack of capabilities is to a certain extent due to the trigger-response interaction pattern that frames the exchanges of Web services with third parties. Adhering to this interaction pattern means that a Web service only performs the requests it receives without considering its internal execution state, or even questioning if it would be rewarded for performing these requests (e.g., to be favored over similar Web services during selection). There exist, however, several situations that insist on Web services self-management so that scalability, flexibility, and stability requirements are satisfied. The objective of this chapter is to discuss the value-added of integrating context and policies into a Web services composition approach. The rest of this chapter is organized as follows. Section 2 presents the approach to compose Web services. Section 3 discusses the impact of policies on Web services and specifies the policies for the behavior of Web services. Section 4 is about exception handling. Section 5 reviews some related works. Finally, Sect. 5 concludes the chapter. © 2008 Springer-Verlag Berlin Heidelberg.