Web Service Choreographies
Guest Editors' Introduction • Marco Aurélio Gerosa and Valérie Issarny • October 2011
Service-oriented computing has been the focus of tremendous research and technology development over the last 10 years and is now acknowledged as a central paradigm for Internet computing. In this context, researchers have looked at service composition from two complementary points of view: service orchestration and choreography. Although several software systems and technologies have supported Web service orchestration, research on Web service choreography is still at its earliest stage. On the other hand, because choreographies have no central element of control, they offer a promising approach to coping with the scalability issue that arises from the Future Internet view (see more details in the Related Links). In this month's theme, we would like to share a few articles about service choreographies that highlight the work that's been done in the last decade.
"Service-Oriented Computing: State of the Art and Research Challenges" gives a good overview of service-oriented computing and puts services orchestration and choreographies into context, presenting some research challenges of the area. "Web Services Orchestration and Choreography" provides a more in-depth understanding of the underlying concepts of and differences between these two models of Web service composition, describing some standards, technologies, and examples.
Regarding languages for the description of choreographies, "Choreographing Web Services" presents a language for Web service choreographies that is based on Pi-calculus, a formal foundation that enables model checking before the choreography enactment (the execution of a choreography). This article also presents key points in relation to how choreographies can be specified, verified, and enacted . The authors compare the proposed language with WS-CDL, the W3C candidate recommendation. Another language, which was recently adapted to describe choreographies, is OMG's BPMN2 (Business Process Model and Notation). This language gained specific elements to describe how business participants coordinate their interactions, focusing on their message exchanges.
"An Integrated Workbench for Model-Based Engineering of Service Compositions" also uses a formal approach to analyze and validate choreographies. This article provides a comprehensive view of the work of the authors, who discuss different approaches for the behavioral analysis of service composition and provide a set of tools integrated into an IDE (integrated development environment) to aid choreography designers.
To conclude, we suggest reading "Rule-Based Coordination of Distributed Web Service Transactions," which discusses the problem of coordinating the participants in a choreography without depending on the specific party that initiated the process. Choreography synthesis and coordination are still open problems when dealing with large-scale choreographies.
We sincerely hope that you will enjoy reading this theme. These articles should give you some useful background information on a range of service choreography topics. Check the Related Links for further information. Finally, we would like to thank Dejan Milojicic, Brooke Miner, Guilherme Nogueira, and Gustavo Ansaldi Oliva for their support for this theme.
http://www.choreos.eu), which aims to offer a middleware and a dynamic development process for ultra-large-scale service choreographies. Contact him at gerosa at ime dot usp dot br.Marco Aurélio Gerosa is a professor in the Computer Science Department of the University of São Paulo (USP) and is the leader of its Software Engineering and Collaborative Systems research group. He also participates in the CHOReOS project (
Valérie Issarny is "Directrice de recherche" at INRIA and leads the INRIA ARLES project team. She is the scientific leader of the CHOReOS project. Contact her at valerie.issarny at inria dot fr.