A version-based transformation proxy for service evolution

Service Oriented Computing (SOC) has emerged as a new computing paradigm that has services as the building blocks to distributed applications. SOC supports rapid development, easy composition and low cost production of distributed applications as services, promoting interoperability. Interoperable applications are however not under the control of a single administration hence implementation detail is abstracted from other administrations. Following the web services architectural model, a service provider may not be in full view of the service requestors consuming his offered services, hence a mechanism to support the existing service requestors in the event of changes made to a service, need to be put in place. This will help to reduce the full impact of unannounced service changes on the service requestors. This paper presents the design and implementation of an approach to gracefully change a service from one version to the next while maintaining support for the existing services. The paper introduces a proxy-based service transformation model to convert messages sent between any service provider-requestor pair to match the version implementation of the requestor. The feasibility and applicability of this model is demonstrated through a prototype.