Abstract
Web services are becoming the dominant paradigm for distributed computing and electronic business. This has raised the opportunity for service providers and application developers to create value added services by combining web services. Several web service composition solutions have been proposed, e.g. WSFL and BPEL4WS. However, none of the existing solutions addresses the issue of service composition reuse and specialization, i.e. how applications can be built upon existing simple or composite services by reuse, restriction or extension. In this article we propose the concept of Service Component that packages together elementary or complex services and provides composition logic and semantics. Within the framework of Service Components we examine different aspects of composition reuse and specialization. A specification for web component reuse and specialization is provided, and possible solutions to support this specification are presented. To demonstrate our framework we provide an overview of ServiceCom, the tool that implements the Service Component concept, supporting reusable web service composition specification, combination, and execution.