RE: [soa-rm] Semantic Meaning of Message

["Vyas, Neeraj" <Neeraj.Vyas@ca.com>]

With respect to the question -- If "message" is too "concrete", what is
the abstraction? 
          I think abstract concept could be Service Request, Service
Response and Service Fault. So in any case service consumer will send
the request to actual service to consume it and would accept a response
from it, or in case of failure of service execution it would except the
cause of it (fault information). So in my opinion while defining a SOA
reference model we need to define what request/response/fault model one
should use. Concrete concept can be Message, Event, Input/Output
Parameters, Exceptions, etc. based on the communication channel one is
using. Service can be defined as Request only or Request-Response, this
information can be collected from the service meta model.  


Thanks and Regards
Neeraj Vyas
CA Computer Associates
neeraj.vyas@ca.com

-----Original Message-----
From: Gregory A. Kohring [mailto:kohring@ccrl-nece.de] 
Sent: Thursday, March 31, 2005 2:11 PM
To: soa-rm@lists.oasis-open.org
Subject: [soa-rm] Semantic Meaning of Message

Hi,

OK, I have looked at all three examples Duane gives and found that
while none of them explicitly use the term "message", they all
define concepts which have a similar semantic meaning.

The RCS reference model, for example, uses the word "event" in much
the same way an web service person would use the word "message".

The OSI reference model is concerned about communication protocols
and how they interact. It does not use the word "message", but does
talk about exchanging "data" between protocols.

The ITA reference model, again does not use the word "message", but
does use the word "protocol" in a way which can be interpreted as a
"message exchange pattern".


So, while these reference models do not use the word "message", they
do use terms denoting a similar concept.


If "message" is too "concrete", what is the abstraction?


Several posters have suggested that some form of "communication" is
implicit in the definition of a service and therefore does not have
to be explicitly mentioned.  But doesn't this go against the idea of
building a reference model?  Shouldn't a reference model explicitly
define all of its elements?  I would argue that anything which is not
an implementation detail should appear in the reference model. (How
you implement the message is an implementation detail, but not the
concept of the message itself.)


Cheers,

Greg


-- 
======================================================================
G.A. Kohring
C&C Research Laboratories, NEC Europe Ltd.
======================================================================