Web Service Composition Using a Deductive XML Rule Language

N. Bassiliades, D. Anagnostopoulos, I. Vlahavas, “Web Service Composition Using a Deductive XML Rule Language”, Distributed and Parallel Databases, Ahmed K. Elmagarmid (Ed.), Kluwer, Vol. 17, No. 2, pp. 135-178, 2005.

Web Service Composition, Service Domain, Deductive Object Oriented Database, XML Rule Language.

This paper describes a knowledge-based Web Service composition system, called SWIM, which is based on the Service Domain model. Service Domains are communities of related Web Services that are mediated by a single Web Service, called the Mediator Service, which functions as a proxy for them. When a requestor sends a message to the Mediator Service one or more of the related Web Services are selected to dispatch the message and the results returned are aggregated to a single answer to the requestor. Mediator Services can be further composed to more complex Mediator Services that combine several selection and aggregation algorithms among many heterogeneous web services. The system utilizes the X DEVICE deductive XML rule language for defining complex algorithms for selecting registered web services, combining the results, and synchronizing the workflow of information among the combined web services in a declarative way. In the paper, we demonstrate the flexibility and expressibility of our approach for composing Web Services using several e-business examples, covering most of the workflow patterns found in a comprehensive workflow management system [2].