Service aggregation using relational operations on interface parameters

Abstract

Many practitioners recommend the use of coarse-grained services that minimize the number of messages and avoid the need to maintain state information between invocations. However, when considered from a software engineering perspective, coarse-grained services suffer from a number of significant drawbacks, including limited reuse and difficult composability. An important challenge for the developers of service-oriented applications is to determine appropriate level of service granularity to ensure that services are reusable and at the same time have good performance characteristics. Decisions about service granularity need to be taken in the context of a methodological framework rather than using ad hoc heuristics. In this paper we describe a method for service aggregation that uses relational operations over interface parameters to assemble services from low granularity atomic service operations. We illustrate the impact of service aggregation on cohesion and coupling using examples and discuss service granularity in the context of application requirements. © Springer-Verlag Berlin Heidelberg 2007.