W3C home > Mailing lists > Public > www-ws-desc@w3.org > April 2002

Re: multipe protocols/bindings that implements serviceType [Re: slides from my presentation on issues with the core spec]

From: Aleksander Slominski <aslom@cs.indiana.edu>
Date: Thu, 25 Apr 2002 18:37:19 -0500
Message-ID: <3CC8932F.5FDE1EDA@cs.indiana.edu>
To: Sanjiva Weerawarana <sanjiva@watson.ibm.com>
CC: www-ws-desc@w3.org
Sanjiva Weerawarana wrote:

> > however requiring for service that implements serviceType
> > to have exactly one binding for each portType makes it impossible
> > to provide multiple access mechanism to service (multiprotocol),
> > for example SOAP/HTTP and EJB/RMI as equivalent protocols
> > to interact with service.
> No, I don't think so: it just means that different binding selections
> is done at a serviceType granularily and not at a portType granularity.
> That is, right now if you have 3 portTypes (pt1, pt2 and pt3) and 2
> bindings (ejb-pt1, soap-pt1, ejb-pt2, soap-pt2, ejb-pt3, soap-pt3) for
> each one, then its not clear whether you have to use the same binding
> type for both portTypes or not. So can I choose ejb-pt1/pt1 and
> soap-pt2/pt2? Not clear, but most probably not.

that may be very good choice, for example soap is event notification or
control port but ejb port is used for high-speed transfer of large data
and using soap binding would make very-slow data transfer port ...

> If we group these via
> serviceType/service, then its clear that binding choices offer different
> services and that binding choices are offered as different services
> for the same serviceType.

however that also means that i will need two separate service elements:
one for soap binding and another for ejb bindings for each given serviceType.
but unfortunately there is no way for the client to discover _automatically_
that those two services are actually pointing to the same "instance"
(actually i think that by default client should assume that service elements
describe unrelated services ...)

> > finally: if service implements serviceType doe sit mean that service ports
> > are accessing the same logical instance of service?
> Yes, a given implementation of a serviceType should represent one logical
> instance of a service. Is that what you're asking; I'm not clear on the
> question?

is it specified somewhere in WSDL?

what i am getting into is the notion of "should" or "must"
- can i _always_ safely assume that ports in service elements
are related and access the same service instance?


Received on Thursday, 25 April 2002 19:37:24 UTC

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