Rounding Up Web Services Intermediaries


As vendors fine-tune their products, add features, and improve usability, WSI options are getting better. Over the last few months, several new versions of WSI products have popped up: Actional Looking Glass 5.0, AmberPoint SLM (Service Level Manager) 2004, Grand Central BSN (Business Services Network) 4.0, and Infravio Ensemble 4.1 (the component I tested is now known as X-Broker).

Each of these products differs significantly in their approach to intermediating Web services, but a cursory review of their feature sets doesn't readily reveal that difference. The significant contrast is in the metaphors they use for management and the presentation of information; each WSI emphasizes different aspects of the intermediary game. Grand Central 4.0 is a hosted service, whereas Actional's approach zeroes in on service monitoring; Infravio uses contracts to define relationships; and AmberPoint SLM manages performance with service-level objectives.

Doing a 4-way head-to-head comparison of Web services intermediaries was a bigger job than I thought it would be. The job is made tougher by the fact that none of these products are trying to solve exactly the same problem. Nevertheless, I found them all to be quite capable with each having specific strengths. I continue to recommend Grand Central's Business Services Network to people wanting to explore the capabilities of an intermediary because its so easy to get set up and developer accounts are free.

The piece also included a sidebar on BPEL:

Because BPEL is XML based, it's not much to look at. Programming language designers call the features used to make a language readable and pretty "syntactic sugar;" BPEL is syntactic arsenic. There seems to be no compelling reason to base BPEL on XML except that XML is the syntax of the Web.

BPEL's constructs will be familiar to anyone who has programmed in a language that allows parallel execution flow and asynchronous invocation -- good programmers will catch on pretty quickly. And because BPEL is a standard supported by large vendors -- it was defined by BEA Systems, IBM, Microsoft, and a handful of other vendors and proposed to OASIS as a technical standard in 2003 -- support tools should be plentiful.

Consequently, most people probably won't write BPEL directly, but rather use a graphical tool that ultimately generates the BPEL. Grand Central's Business Services Network, for example, provides a convenient engine for executing BPEL. Collaxa sells a BPEL execution engine as well as a BPEL design tool.
From InfoWorld: Is BPEL the real deal?: July 02, 2004: By Phillip J. Windley
Referenced Tue Jul 06 2004 21:33:09 GMT-0400