A Petri Net-Based Method for Data Validation of Web Services Composition

For some time, the modeling and verification of web services composition are focused on control flow. Recent years, data validation has gained researchers´ attention too, as it is important to the correct execution of the composed web service. To verify data-related requirements of web services composition, we present a Petri net-based method for the data validation of web services composition developed with Web Service Business Process Execution Language. Data-flow related aspects of the WS-BPEL process are described with WS-CPN, which is a special kind of Colored Petri net supporting the description of XML Schema types. In WS-CPN, data types are described by CPN ML, a description language for Colored Petri net. We present WS-CPN models for various activities of a WS-BPEL process, which can be combined together to obtain the WS-CPN model for the entire composition process. Data validation problems in web services composition including redundant data, lost data, inconsistent data and misdirected data are discussed, and the methods for validating these problems are given based on WS-CPN.