Control flow complexity metrics for petri netbased web service composition

Web services technology is an effort to build a distributed computing platform over the network, and it can implement systematic application-to-application interaction on the Web. In recent years, this new technology has been widely adopted for constructing distributed applications. However, how to precisely measure the controlling complexity of Web service composition (WSC) is a very difficult task due to its characters such as heterogeneity, distributed and loose-coupling. In the paper, we mainly concern on the complexity measurement of Petri net-based business process in Web service composition. Two metric sets are presented through analyzing the WSC's execution logics and dependency relations in workflow. The first one is count-based metric set, and includes seven metrics such as number of place, average degree of transition, transfer number per service and cyclomatic complexity. The second is an execution path-based metric set, which includes average execution path complexity (AEPC) and its extension based on cognitive informatics. In addition, two real-world WSCs are used to validate our measurement methods. The results show that our metrics are effective and rational, and have high practical value for WSC analysis and maintenance. © 2010 ACADEMY PUBLISHER.