Re: [wsrf] WS-RAP; section 2.3 - WS-Resource definition

[Rich Thompson <richt2@us.ibm.com>]

One of the things I appreciate about
the definition set in WS-RAP is that it clearly separates a resource from
a WS-Resource. I agree that the portlet is a WS-Resource, but it is encapsulating
multiple resources rather than multiple WS-Resources. The essence of my
question is whether the web service endpoint is allowed to operate on multiple
resources or whether there is a strict one-to-one mapping of resource to
WS-Resource. Clearly the portlet could invent a wrapper resource that merely
encapsulates the underlying resources, but why should that be required?


On the ramifications of allowing this
broadening, I think we all agree that this can be done without the client
being aware of it. The client is interacting with a WS-Resource and it
has no idea of the meaning of the various parts (could include a separate
identifier for each resource) of the endpoint that it has been given, only
that it has to follow the contract of the binding to the WS-Resource that
is in use.

Rich

Tom Maguire/Hawthorne/IBM@IBMUS

10/05/2004 02:56 PM

To	Rich Thompson/Watson/IBM@IBMUS
cc	wsrf@lists.oasis-open.org
Subject	Re: [wsrf] WS-RAP; section 2.3 - WS-Resource definition

So I guess I'm struggling with this a bit.  From the client's perspective
you have a single
WS-Resource.  That WS-Resource has an identifier.  As you mentioned
the
client would
not need to know or care that multiple resources are involved.  In
WS
Remote Portlet it
sounds as if there is a need to do a composition of multiple (different
types of )
WS-Resources and the "portlet" endpoint is responsible for dispatch
to the
underlying
"encapsulated" WS-Resources.  In this model I think the
WS-Resource is the
remote portlet.
That remote portlet has its own identifier.  That identifier is used
as a
resource disambiguator
to the "collection" of related WS-Resources not to the individual
WS-Resources of the collection.

So I agree that clients should not care but I would also argue then that
from the clients
perspective there is just one WS-Resource and that the definition of a
WS-Resource
is correct from that perspective.

Tom

Problems cannot be solved at the same level of awareness that created
them.  —Albert Einstein
T o m   M a g u i r e

STSM, On Demand Architecture
Poughkeepsie, NY  12601

Rich Thompson/Watson/IBM@IBMUS wrote on 10/05/2004 01:43:27 PM:

>
> Not quite our situation. Certain operations will need to access more
> than one resource during the processing of a single message. How the
> set of resources is constructed and referenced by the endpoint would
> be a matter between the factory and the resource disambigurator. I
> would hope the client would not need to know or care that multiple
> resources are involved and am raising the case seeking that both the
> language and semantics permit such a pairing of a web service and
a
> set of resources within a single endpoint without requiring
> knowledgeable clients.
>
> Rich
>

>
> Steve Graham/Raleigh/IBM
> 10/05/2004 09:51 AM
>
> To
>
> Rich Thompson/Watson/IBM@IBMUS
>
> cc
>
> wsrf@lists.oasis-open.org
>
> Subject
>
> Re: [wsrf] WS-RAP; section 2.3 - WS-Resource definitionLink
>
>
>
> Rich:
> To clarify, your situation is such that a Web service deployed at
> some URL is the access point for a collection (potentially many)
resources?
>
> Given my assumption is true, I don't see why you have come to the
> conclusion that the definition of WS-Resource precludes it.  The
> examples in the WSA embodiments (sections 3.1 and 3.2) suggest this
> pattern where a single web service is front ending 2 resources.
> Note that it is the pair (web service + resource) that is the WS-
> Resource. So in the examples in the WSA embodiments contain 2
WS-Resources.
>
> Does this help?
>
> ++++++++
> Steve Graham
> (919)254-0615 (T/L 444)
> STSM, On Demand Architecture
> Member, IBM Academy of Technology
> <Soli Deo Gloria/>
> ++++++++
>
>
> Rich Thompson/Watson/IBM@IBMUS wrote on 10/05/2004 08:53:02 AM:
>
> > While I haven't finished working through exactly how the WSRP
> protocol could best
> > leverage WSRF, I (and others on the WSRP TC) are leaning towards
> the at least some
> > of the web service endpoints containing references to a set of
> resources rather
> > than just one. The proposed definition ("A WS-Resource is
a Web
> service through
> > which a resource can be accessed.") excludes such use cases.
Any reason
the
> > definition can not be broadened to "A WS-Resource is a Web
service
> through which a
> > set of one or more resources can be accessed." This would
carry
> into many other
> > places in the text where the resource is referred to in the singular.
> > Rich Thompson
> > OASIS WSRP TC Chair