Frank Leymann has given a tutorial at the ICWE 2007 in Como, Italy, on the 16th of July during which he has also presented the SUPER project.

Title

"Web services, their composition,
and their impact on application structures"

Topic

The origin of Web service technology (making Enterprise Application Integration EAI much easier) is discussed, such that the problems to be solved by Web services are understood. The key standards for Web services are presented: SOAP, WSDL, WSPolicy, BPEL, and WS-Coordination. SOAP is the messaging container for exchanging application payload and metadata between a requestor and a Webservice. WSDL allows to describe the functional capabilities of a Web service. WS-Policy provides a grammar and container for specifying non-functional properties of Web services. In order to compose more complex Web services from already existing services, BPEL is used. WS-Coordination is needed for agreement between ad hoc collections of Web services.

The relation between these standards is described and how they are reflected in corresponding middleware (“service bus”). The role service discovery is worked out and how this results in virtualization of functionality. The upcoming importance of semantic Web technology (RDF, OWL,…) for discovery is explained. A quick review on the goals of Grid computing (i.e. virtualization of compute resources) will make clear why Grid infrastructure and service bus currently converge, and what the key ingredients of this convergence are.The role of business processes (BPEL) in composing applications is described. Two-level-programming, as paradigm for such compositions, is explained.

The impact of the resulting application structure for outsourcing (parts of) applications will become clear. Required technology for supporting outsourcing in a dynamic fashion will be sketched (provisioning, utility computing). Actual trends in extending BPEL to broaden its applicability are sketched at the end of the tutorial: supporting human interactions (BPEL4People), supporting subprocesses (BPEL-SPE), and combining semantic Web services with BPEL-BPEL4SWS).

Schedule

Monday July 16th, 9:00 to 12:30

Presenter

Prof. Dr. Frank Leymann
Institute of Architecture of Application Systems
University of Stuttgart
Germany

Additional info

More info on: ICWE 2007 Web Page