A Model-based Approach for Diagnosing Fault in Web Service Processes

Web services based on a service-oriented architecture framework provide a suitable technical foundation for business process management and integration. A business process can be composed of a set of Web services that belong to different companies and interact with each other by sending messages. Web service orchestration languages are defined by standard organizations to describe business processes composed of Web services. A business process can fail for many reasons, such as faulty Web services or mismatching messages. It is important to find out which Web services are responsible for a failed business process because we could penalize these Web services and exclude them from the business process in the future. In this paper, we propose a model-based approach to diagnose the faults in a Web service-composed business process. We convert a Web service orchestration language, more specifically BPEL4WS, into synchronized automata, so that we have a formal description of the topology and variable dependency of the business process. After an exception is thrown, the diagnoser can calculate the business process execution trajectory based on the formal model and the observed evolution of the business process. The faulty Web services are deduced from the variable dependency on the execution trajectory. We demonstrate our diagnosis technique with an example.

A Formal Approach for the Validation of Web Service Orchestrations

A web service composition is considered as a real revolution in SOA (Service Oriented Architecture). It is based on assembling independent and loosely coupled services to build a composed web service. This composition can be described from both a local or a global perspective by respective orchestration or choreography. The validation of web service orchestrations is the main topic of this work. It is based on the verification of two classes of properties: generic and specific properties. The former can be checked for any invoked web services whereas the specific properties are different interdependence relationships between activities within an orchestration process. These properties cannot be directly verified on the orchestration process, so, the authors have to use formal techniques. In this paper, they propose a formal approach for the validation of web service orchestrations. This work adopts WS-BPEL 2.0 as the language to describe the web service orchestration and uses the SPIN model-checker for the verification engine. The WS-BPEL specification is translated into Promela code which is the input language for the SPIN model-checker, in order to check generic and specific properties expressed with LTL (Linear Temporal Logic).

A JBPM-Based Workflow Engine for Web Services Orchestration

A novel workflow engine for Web service orchestration, JBPM4WS is proposed in this paper. JBPM4WS is built on JBPM, a well-known workflow engine. We extend the workflow language JPDL, which is adopted by JBPM, to support service invoking. JBPM4WS engine adopts four-layer architecture, and is implemented based on some open-source frameworks, such as Hibernate, CXF and JAXB.