Towards a Data Complexity Metric Set for Web Service Composition

Web services technology and the corresponding software have been widely acknowledged in recent years. However, some new features of Web service-based software such as heterogeneity and loose-coupling bring great trouble for its latter maintenance and comprehension. The complexity analysis of such system is helpful to solve it. At present, the existing researches mainly concerns on the complexity metrics for control flow. In the paper, we give a data complexity metric set as an effective complement. The data complexity can be measured from two perspectives: data traffic and data dependency. For the first one, the volume of data flow is scaled by analyzing service´s parameters and their data types. The second one is implemented by analyzing the definition and use of variables in BPEL program dependence graph. Based on the def-use pairs, the metric subsets about degree, def-use chain and entropy are addressed. Based on the proposed metric set, we can more fully understand the Web service-based system. In addition, it can also facilitate the performance or defects analysis for such type of system.