RE: [soa-rm] Service Consumer in RM or not?

[Rex Brooks <rexb@starbourne.com>]

Hi Folks,

I thought we did put this issue to rest, at least in the sense of 
providing a main topic for our next meeting. The following quote is 
the last paragraph of the minutes/meeting notes for our last meeting;

"After much discussion, the idea of having 2 documents was proposed - 
one focused on the Service Oriented Reference Model, and the other 
one focused on the Service Oriented Architecture RM.  The one 
currently being worked would be the SO RM, and would be conceptually 
similar to a RM for a house.  The other document would need to be 
started, and would conceptually be similar to the idea of a RM for a 
community.  It was proposed that this idea be a main topic of the 
next TC meeting."

I think it was Rebekah, but it might have been Patti who suggested 
that we might want to break this whole issue into a succession of 
profiles: Service, Service Consumer, SOA, taking each component in 
isolation first then bringing the components together to model the 
Architecture (with a capital A). I happen to like that idea very much.

Ciao,
Rex


At 11:04 AM +0200 6/7/05, Peter F Brown wrote:
>Duane:
>I'm not actually advocating one or the other approach (I might even own up
>to being a little confused), with or without "service consumer", but tried
>only to encapsulate the different views that came out of the meeting.
>
>Running the whole through my sluggish brain, I suppose I do have to come
>down one side or another, and I come up with:
>
>I agree with your refinement that a service is an invokable event, rather
>than an event per se. Invokable, not invoked - I think that is your point.
>It underlines intent.
>
>[Careful with your analogy with "message" however: There does need to be an
>intention for a content to be transmitted to another entity for it to be
>considered as a message, otherwise it is simply a document: I would agree
>however that it does not need to have been successfully transmitted or
>received, for it to be a message. Again, it underlines intent.]
>
>Equally, and by analogy, a service does not require for there to be a
>consumer, in order to be considered as a service. We need therefore to
>establish only an intention and capability to provide a service (implicitly,
>providing it to another entity, the consumer): hence service-oriented. The
>RM should thus be the model from which any service-oriented architecture can
>be derived, no more.
>
>I would still argue that service consumer and service provider are two roles
>of the same abstract entity, "agent"; BUT accept that this is not within
>scope of the SOA-RM. I think your suggestion of including this as another
>non-normative text might help to satisfy those who wish nonetheless to
>answer the concern about situations in which a provider may in some
>situations be a consumer or vice-versa.
>
>-Peter
>
>
>-----Original Message-----
>From: Duane Nickull [mailto:dnickull@adobe.com]
>Sent: 07 June 2005 01:40
>To: peter@justbrown.net
>Cc: 'SOA-RM'
>Subject: Re: [soa-rm] Service Consumer in RM or not?
>
>Hi - I'm back!!
>
>Comments inline:
>
>Peter F Brown wrote:
>
>>1) A service is an event
>>
>DN - a "service invocation" is an event. The "service" itself is not an
>event IMO, it is an invoke able entity..
>
>>representing a collaboration between two parties for the use of defined
>>resources: a "service RM" would be concerned with representing both
>>parties (provider and consumer), the duality of their interaction
>>through the event and the use of resources...
>>In this approach:
>>- service consumer would definitely be in, as one side of the
>>event-based duality (provider<>consumer);
>>- a further level of abstraction can be modelled, that of "agent", to
>>highlight the shared properties of both provider and consumer. In this
>>manner, it would be easier to answer the problem "how do we model the
>>situation where a service provider can also be a consumer, and
>vice-versa?".
>>They are both agents. Whether they are consumers or providers would
>  >therefore be modelled as a "role" in agent.
>>
>>2) A service is a "directed collaboration" between two parties:
>>directed in the sense that one party provides a service to another: a
>>"service provision RM" would only be concerned with one side of the
>>duality, representing the service provider, irrespective of whether the
>>service is used, or whether there is a consumer at the end of the "pipe"...
>> 
>>
>I would like to call for a vote on this too to put it to bed for once an
>all.  My assertion = If I architect something with a service, a consumer
>does not have to be present for it to be "service oriented".   Nor do
>messages, networks, signals, pings, security, encryption etc etc.   This
>is much the same as stating that a "message" does not have to be sent in
>order for it to be a "message".  It can exist with or without being
>transmitted.
>
>If we do go the way of the service provider and service consumer, this could
>be done in an illustrative (non-normative) manner in the RM or (and I favor
>this idea) as part of a reference architecture.  If we do vote to include
>the SC, we then have to open up the RM to everything else that follows which
>means that it won't be a RM, it will be architecture.
>
>I had hoped we could gain consensus on this and avoid a vote however I feel
>a vote may be inevitable.
>
>BTW - has anyone else noticed that the list is very slow today? It took
>5 hours for my last message to come back to me via this list?
>
>Duane


-- 
Rex Brooks
President, CEO
Starbourne Communications Design
GeoAddress: 1361-A Addison
Berkeley, CA 94702
Tel: 510-849-2309