[ogsa-wg] Virtualization: How do we specify notifications?

[Dave Berry]

Dear OGSA WG,

In the object-oriented world, components such as Java Beans or ActiveX
controls are typically defined by a set of properties, a set of methods
and a set of events.  In the service-oriented world we have a similar
requirement, dealing with interoperable messages rather than a language
API.  What is the best way to specify the notifications that a service
or interface can send?  

The OGSA document describes a virtualization as a "common set of
abstract interfaces available for a set of similar resources, thereby
hiding differences in their properties and operations".  To this we
somehow have to add the notifications that can be generated, as these
are an essential part of virtualization.  Are the notifications part of
an interface?  Are they actually specified in any of the metadata for a
service?

The OGSA document defines an interface as follows: "In a
service-oriented architecture, a specification of the operations that a
service offers its clients".  Should this be extended to include
properties and/or notifications?

This is a live issue for the Data Architecture document.

Best wishes,

Dave Berry
Research Manager, National e-Science Centre
15 South College St., Edinburgh
Tel: +44 131 6514039