Restructuring Web Service Interfaces to Support Evolution

This paper presents an overview of a scheme (RESWS) to enable Web Service providers to be able to evolve their service interface in a non-backwards compatible way and still maintain compatibility with existing consumers. The need for a non-passive approach to evolving services while still remaining backwards compatible is highlighted and presented based on a clear need identified within the literature. Based on graph rewriting theory, the set of refactorings was formally represented as transformations through rewriting rules and enables a set of preconditions to be defined for each transformation. A demonstrator has been developed to implement the RES-WS scheme as a message mediator which interprets the chain of primitive refactoring transformations required to carry out a particular complex transformation. Experimental validation was performed to demonstrate the feasibility and effectiveness of the message mediator for an upgraded Web Service against its QoS constraint.