BPEL

At CBDI, we are generally supportive of BPEL. However, we do not see it as a complete solution to business collaboration. We have raised a number of issues over the past two years.

In business terms, the basis for collaboration between autonomous business entities is a service contract. This suggests a design process in which contracts are paramount - such as Design by Contract. One of our concerns about the web service stack (including BPEL) is that it lacks proper support for contracts and assertions. We proposed that service contract should be a first-class construct, and we have yet to be convinced otherwise. We look forward to seeing what emerges from WS-Choreography.

Secondly, we think the ideal of distribution or federation remains some way off. For example, while WS-Transaction supports distribution, BPEL assumes that the process management is hosted on a single engine, although there have been hints that a future version of BPEL will support distributed process management. In the meantime, some people are experimenting with alternative approaches to distributed process management, such as OGSA.

See for example Grid Web Services and Application Factories (pdf)

Thirdly, there appears to be a widespread assumption that the orchestration or choreography is established at design time, with only minor modifications (such as the introduction of new, interchangeable partners) at run time. In time we should progress to real time orchestration.

See CBDI Newswire 22nd May 2003 and 28th May 2003 (free access).

See CBDI Reports From Web Services to Web Collaborations (Nov 2002).