Generic Web Services Extensible Functionality with Stable Interface

Extending the functionality of Web services without invalidating the code of existing clients has been a challenging task. This paper proposes a new interface design technique called "Generic Web Services" that preserves a service\´s backwards compatibility while enriching its functionality. This is accomplished by applying interface relaxation technique - shifting the semantics of a service\´s API from design time to runtime by using identity parameters. The paper gives an example illustrating the idea on a Web service from SAP Enterprise Services Workplace.