WS-Eventing emerges (hesitantly) as a standard

If there’s one aspect of the Web applications world that you can be certain of, it is that every time you turn around, there will be a new standard. Indeed, this is arguably, what makes Web applications so different from other technology domains: Central to Web applications being successful is the need to create common foundations for interoperation and collaboration.

OK, enough philosophy – today I have one of these emerging standards for you and it is one that I think will become very important in Web applications. The standard is WS-Eventing (see links below).

Jointly designed and promoted by BEA Systems, Microsoft and Tibco Software, WS-Eventing provides a common method for events to be communicated within and between XML-based Web services.

WS-Eventing’s goal is to enable Web services to send and receive information about events regardless of where the event originates from and is intended to work with other WS specifications. WS-Eventing defines how a Web service, the ‘event sink’, can register (a “subscription”) to another Web service, the  ‘event source’, to receive messages (“notifications”) about events.

The originators of the specification describe the need for WS-Eventing as “”Events are occurrences in the real world that can trigger action in software: a phone rings, an order is placed, a package is shipped, a printer runs out of paper, your favorite team scores, a stock hits a new high, etc. These real-world events need to be mirrored within the technologies that have become fundamental to peoples’ lives and to businesses … Without a common way to communicate events, developers have been forced to create ad hoc solutions that are incomplete and inflexible. With WS-Eventing, every Web service can send and receive information about events that have occurred, regardless of whether the event is originating in the firmware of a simple device or in large scale enterprise systems.”

The formal models for WS-Eventing are an XML schema and WSDL specification and it supports both SOAP 1.1 and 1.2. 

If you want to get a jump start on understanding the architecture and details of WS-Eventing I recommend two online articles written by Bruce Williams: “WS-Eventing for Dummies” and “WS-Eventing Part II: The Subscription Process”.

It is unfortunate that IBM, which has worked closely with Microsoft and the others in developing other WS- specifications is not interested in WS-Eventing. IBM’s interest in this area lies in its MQ Series middleware, which the company claims is better suited to large-scale use than WS-Eventing. Karla Norsworthy, IBM’s director of dynamic e-business technology was quoted in “Computer Business Review Online” as saying: “We don’t want to introduce new technology and prohibit [customers] from solving problems… like large scalability.”

Despite IBM’s disinterest, I predict that WS-Eventing will become the more widely used standard.