Transparent Reputation Management for Composite Web Services

The dependability of composite services is largely affected by their constituent Web services. Composite services have to operate in an open and dynamically changing environment in order to leverage the best performing services available at the moment. Hence, there is the need for an efficient mechanism to provide reliable service rankings. In this paper we present a novel, generic, and customizable reputation infrastructure to automatically and transparently monitor the execution of composite services, taking both functional and non-functional properties into account. The experienced Web service quality-of-service is communicated to a configurable reputation mechanism that publishes service rankings. Our reputation infrastructure supports notifications upon changes in service reputation, enabling self-tuning and self-healing properties in the execution of composite services. We implemented our architecture using standard technologies, such as BPEL and JavaEE. Performance measurements show that our infrastructure causes only moderate overhead.