Introducing BPEL4WS 1.0 Well, BPEL4WS was introduced last year and has already gone into version 1.1 draft release but this article on Web Services Journal provides a very good introduction of BPEL4WS and shows how it builds on the features offered by WS-Coordination and WS-Transaction.
BPEL4WS is at the top of the WS-Transaction stack and utilizes WS-Transaction to ensure reliable execution of business processes over multiple workflows, which BPEL4WS logically divides into two distinct aspects. The first is a process description language with support for performing computation, synchronous and asynchronous operation invocations, control-flow patterns, structured error handling, and saga-based long-running business transactions. The second is an infrastructure layer that builds on WSDL to capture the relationships between enterprises and processes within a Web services-based environment. Taken together, these two aspects support the orchestration of Web services in a business process, where the infrastructure layer exposes Web services to the process layer, which then drives that Web services infrastructure as part of its workflow activities. The ultimate goal of business process languages like BPEL4WS is to abstract underlying Web services so that the business process language effectively becomes the Web services API. While such an abstract language may not be suitable for every possible Web services-based scenario it will certainly be useful for many, and if tool support evolves it will be able to deliver on its ambition to provide a business analyst-friendly interface to choreographing enterprise systems.