Analysis and Re-engineering of Web Services

Abstract: To an increasing extend software systems are integrated across the borders of individual enterprises. The Web Service approach provides group of technologies to describe components and their composition, based on well established protocols. Focused on business processes, one Web Service implements a local subprocess. A distributed business processes is implemented by the composition a set of communicating Web Services. At the moment, there are various modeling languages under development to describe the internal structure of one Web Service (e. g. Business Process Execution Language for Web Services BPEL4WS (BEA et al., 2002a)) and the choreography of a set of Web Services (e. g. Web Service Choreography Interface WSCI (BEA et al., 2002b)). Nevertheless, there is a need for methods for stepwise construction and verification of such components. This paper abstracts from concrete syntax of any proposed language definition. Instead, we apply Petri nets to model Web Services. Thus, we are able to reason about essential properties, e. g. usability of a Web Service – our notion of a quality criterion. Based on this framework, we present an algorithm to analyze a given Web Service and to transfer a complex process model into a appropriate model of a Web Service