Reserving Immutable Services through Web Service Implementation Versioning

Widespread adoption of a Web services-based paradigm for software applications will imply that applications will typically have potentially many dependencies upon Web services that they invoke or consume. These invoked services might typically be available from a remote site and be under the administration of third parties. This scenario implies a significant vulnerability of a Web services-based application: one or more of the services which it consumes may become altered, hence potentially “breaking” the application. Such alterations might be such as those that alter the WSDL signature of the service or could be changes to the underlying service implementation that do not change the WSDL signature. In this paper, we will focus on the second of these two cases and will introduce a versioning system that can detect changes to service implementations and that can avoid the breaking of applications that call services in the face of changes to the implementations of those called services.