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

[Tim Banks <tim_banks@uk.ibm.com>]

Dave,  (and Rich)

You said:

> If I have a WS and a bunch of resources, I have a set of WS-Resources
> with a one-to-one correspondence to the resources. Because all the
> WS-Resources share the same WS they can respond to the operations.

If the resources are independent they may respond differently to the same
operation. Some may respond with a fault; how are the different responses
combined? What is the client to make of this? So, it may work in some cases
(perhaps you have some in mind that you could describe) but it isn't
generally applicable because the interface of the components isn't the same
as the interface of the aggregation. You can define a new interface for the
aggregation (probably with some rather vague fault messages in the general
case) but that establishes a new kind of behaviour for the aggregate
resource (singular).


Regards, Tim Banks
IBM TP Architecture & Technology. Hursley, UK.
Phone: External +44 1962 815639, Internal 245639

David Snelling <David.Snelling@UK.Fujitsu.com> wrote on 06/10/2004
09:03:33:

> Folks,
>
> This issue has come up in other discussions I have had, particularly
> with folks less enthusiastic about WSRF. Put generally ...
>
> If I have a WS and a bunch of resources, I have a set of WS-Resources
> with a one-to-one correspondence to the resources. Because all the
> WS-Resources share the same WS they can respond to the operations.
> Rich's question (and that of others) is, can I drive the same operation
> on all WS-Resources at once?
>
> Answer 1: Yes, create a new Disambiguator that refers to the whole
> collection. Steve pointed to this option.
>
> Answer 2: Wrap the set of WS-Resources in a ServiceGroup and drive the
> operation on all WS-Resources through an iterator operation on the
> ServiceGroup (NB: such an iterator has yet to be proposed for
> ServiceGroup).
>
> Answer 3: Allow multiple Disambiguators in a single message. To use
> embodiment 1, create an EPR for the collection that looked like this:
>
> <wsa:EndpointReference>
>
> <wsa:Address>http://localhost:8080/axis/services/UnicorePort</wsa:
> Address>
>     <wsa:ReferenceProperties>
>        <ns1:ResourceDisambiguator xmlns:ns1="http://arcon.fujtsu.com/";>
>        UnicorePort:E5623340-16DA-11D9-9A2A-C83D27C15A63
>        </ns1:ResourceDisambiguator>
>        <ns1:ResourceDisambiguator xmlns:ns1="http://arcon.fujtsu.com/";>
>        UnicorePort:0035B930-16DB-11D9-9A2A-9A608286117E
>        </ns1:ResourceDisambiguator>
>     </wsa:ReferenceProperties>
> </wsa:EndpointReference>
>
> The semantics would require that the client copy both Disambiguators
> into the message and the service could interpret this as "Drive the
> same operation on all the WS-Resources referenced by the Disambiguators
> in the message."
>
> I kind of like this, but I have never been convinced by WSRF critic's
> use cases. Possibly the WSRP use case is a strong enough one.
>
> Note: I don't believe this approach is as straight forward for the
> other embodiments as the above.
>