IBM, Sun Microsystems, and Computer Associates
International have jumped aboard in support of the WS-Eventing
specification for subscribing to web services-based events, joining
original developers Microsoft, BEA Systems and Tibco
Software.
The specification is intended to define a baseline set of
operations that allow web services to provide asynchronous
notifications to interested parties.
For example, an event notification could pertain to shipping of
an order or e-mail arriving. Microsoft officials cited desires for
interoperability between different specifications as reasons why
rivals such as Sun and IBM are climbing aboard.
"I think overall, there was a goal to kind of rationalise the
way this specification was being developed going forward so that it
will factor well with other things that are out there and hopefully
drive a lot of interoperability for customers," said Pete
McKiernan, Microsoft's lead product manager for developer platform
evangelism.
Microsoft plans to support WS-Eventing in the Indigo web
services applications framework to be included in the Longhorn
release of Windows planned for 2006.
IBM has had a similar specification to WS-Eventing, called
WS-BaseNotification, which was submitted to Oasis in April as part
of IBM's WS-Notification specifications submission. But IBM's
participation in WS-Eventing does not spell the end for
WS-BaseNotification and WS-Notification.
The company still plans to support its WS-Notification
specifications to enable publish-subscribe functionality for web
services in its WebSphere application server, said Karla
Norsworthy, director of dynamic business technologies at IBM.
The company's products, however, will be able to communicate
with systems that use WS-Eventing, she said.
"We decided the best [choice] for us was to drive these
[specifications] close together, but it does not change our
commitment to WS-Notification," Norsworthy said. Over the long
term, IBM would like to see WS-Eventing converged with its own
technologies into one specification.
"I think as a long-term strategy, we would love to see that, but
at this point, we are trying to make sure that we can factor these
things [so] that it is easy for them to work together in customer
environments that end up with both of them," Norsworthy said.
WS-Notification supports intermediary brokering technologies for
publish-and-subscribe Web services paradigms, but WS-Eventing
currently does not, she said.
Additionally, the WS-Eventing specification is being updated to
support endpoint references as a more specific way to subscribe to
asynchronous web services notifications than the previous method
support, called Subscription ID, which provided an arbitrary
identifier.
Endpoint references serve as a URL-like mode for addressing a
web service, according to Microsoft. The revisions also clear up
ambiguities and can support new delivery modes that may arise for
asynchronous web services.
An analyst described the collaboration on WS-Eventing as a
victory for interoperability.
"IBM and Sun and Tibco joining Microsoft in its WS-Eventing spec
is definitely a major win for web services and SOA
[service-oriented architecture] adoption," said Ron Schmelzer,
senior analyst at ZapThink.
"I think we are finally seeing convergence and coalescence on a
set of specifications that is gaining market traction. In this
case, it is important for the industry vendors to all agree about
how events and asynchronous publish-subscribe style notifications
will happen in a standards-based way."
Sun's participation in WS-Eventing is part of the company's
collaboration with Microsoft on web services standards, according
to Sun. The company has not yet determined which of its products
will support the specification.
WS-Eventing has not yet been submitted to a standards body such
as Oasis for consideration as an industry standard, but plans are
afoot to do that when the proposal is deemed solid enough, said
Microsoft.
Paul Krill writes for InfoWorld