At 04:17 PM 2003-12-05, Francis McCabe wrote:
This diagram is a revised diagram
for a refactored resource model.
We may, or may not, wish to include the service model for
discovery.
Frank
http://dev.w3.org/cvsweb/~checkout~/2002/ws/arch/wsa/wd-wsa-arch-review2.html#discoveryDiscovery
is
- the act of matching a set of functional and other criteria with a set
of service description
The revised diagram shows [discovery service] about ->
[resource description].
Seems a little messy. What is the relationship between a
"resource description" and a "service
description"?
(Remind me again why discovery is in the resource model?)
I am beginning to feel that discovery is more like a
choreography.
Perhaps we should move discovery to the service oriented model, and add a
box to that diagram labeled [discovery].
Then draw a line from [discovery] to [choreography] with the label
"described by".
That is, discovery is described by a choreography.
That would seem to provide a better way to handle things like the
discussion of UDDI and semantic matching (external but related to
UDDI).
Perhaps a discovery workflow would involve a lookup in UDDI, pass results
to another semantic web service, which passes back a more precise or
expanded UDDI inquiry, then another call to UDDI. This could handle
federation, where the federation is described in terms of a
choreography.
There would not be a single choreography for discovery. There could
be many, each of which could be described by a choreography
description.
The other thing that bothers me a little is that discovery probably
extends beyond the realm of web services (SOAP). For example, the
"index" viewpoint may harvest descriptions without using
SOAP. A discovery choreography might involve SOAP for some pieces,
but also HTTP GET of some description file (not wrapped in a SOAP
envelope). (SOAP 1.2 has the SOAP-response MEP to be used with HTTP
GET, which returns a SOAP envelope. A choreography may need to
involve things that we do not call "web services" since our
definition is constrained to SOAP and WSDL.)
A discovery service could be a composition of other services described by
a choreography.
Thoughts?
Paul