A service pattern model for service composition with flexible functionality
A key feature with service-oriented-architecture is to allow flexible composition of services into a business process. Although previous works related to service composition have paved the way for automatic composition, the techniques have limited applicability when it comes to composing complex workflows based on functional requirements, partly due to the large search space of the available services. In this paper, we propose a novel concept, the prospect service. Unlike existing abstract services which possess fixed service interfaces, a prospect service has a flexible interface to allow functional flexibility. Furthermore, we define a meta-model to specify service patterns with prospect services and adaptable workflow constructs to model flexible and adaptable process templates. An automated instantiation method is introduced to instantiate concrete processes with different functionalities from a service pattern. Since the search space for automatically instantiating a process from a service pattern is greatly reduced compared to that for automatically composing a process from scratch, the proposed approach significantly improve the feasibility of automated composition. Empirical study of the service pattern shows that the use of the proposed model significantly outperforms manual composition in terms of composition time and accuracy, and simulation results demonstrate that the proposed automated instantiation method is efficient.
service pattern meta-model web service composition variability modeling