摘要：Technology is, now, looking for distributed applications to develop and increase its domains. Web services are distributed components that provide functionality applications through network. They can be used by applications written in different languages, and performed in different platforms on different systems. The concept of Web services is essentially based on standard internet protocols, such as UDDI (Universal Description, Discovery and Integration), WSDL (Web Service Description Language) and SOAP (Simple Object Access Protocol) which offer solutions for description, publication, discovery, and interoperability of Web services. However, the complex composition of Web services is not guaranteed by them, therefore, different approaches have been proposed to solve this problem. Current Web services composition approaches range from practical languages aspiring to become standard like Business Process Execution Language (BPEL) to theoretical model like Petri nets. In this paper, we propose Composite Web service model based on Colored Petri-Net (CPN) approach. A Colored Petri-Net is a high level Petri net that provides a significant increase in the expressiveness and compactness of Petri net models. Colored Petri-Net (CPN) has the capacity of formally modeling and verifying complex systems. This paper can assist Web service composition designers and developers to deliver lasting solutions, in concordance with the technology’s critical needs.
关键词：Web services;Composite Web service Petri nets;Colored Petri-Net (CPN)
