Self-adaptive Web Service Compositions

Summary form only given. Self-adaptability and autonomic behaviors are becoming more and more important in the landscape of complex distributed systems, and Web service compositions are a prominent example. Mobile applications require services able to adapt their behavior with respect to different context autonomously, but also more conventional systems demand for reliable services able to cope with "unforeseen" anomalies without human intervention (and without maintaining and redeploying the whole system). These requirements are scarcely supported by current composition languages, like BPEL (Business Process Execution Language), but different research initiatives are trying to overcome these limitations. Some proposals work directly on actual compositions, while others tackle the problem by considering the middleware infrastructure in charge of executing them. Proposed solutions are different and offer many interesting options. The talk surveys the different proposals and proposes a first taxonomy. The result is that the middleware infrastructure plays a key role to provide a holistic and flexible solution for self-adaptive compositions. The brief presentation of a prototype infrastructure for the deployment of reliable and self-adaptive BPEL processes further supports this assumption. The talk concludes by discussing some open issues in the field and by sketching a possible research agenda.