Re: [soa-rm] SOA Definition - the graphic

[Francis McCabe <frankmccabe@mac.com>]

Well, here goes ....

1. There is something fundamentally unknowable about the acted upon  
resources. Certainly the user of a service never gets to see this.  
But even the service provider will often have a hard time pointing to  
this.

  If you are updating a database, but the database is replicated,  
then which is the resource that you are modifying in response to a  
service request? What happens if you swap one database out for  
another? There are more examples here; but the essence is that it can  
be extremely difficult to pinpoint the resource.

  On the other hand, its not necessary, so why bother?

2. There *is* something else that is both measurable and more  
important: what can we expect as a result of a service interaction.

  To fully capture these expectations will, I believe, require a  
grounding in the philosophy of signaling systems. However, from a  
simplistic PoV, you can think of the owner of the service making  
commitments to future actions as a result of service interactions.  
(Well, both the owner of the service and the owner of the service  
using agent.)

  I.e., a service is better viewed as a communications vehicle by  
which service providers and consumers can exchange future  
commitments; these themselves being expressed often as further  
communications.

3. Why do I bang on about this? Because I have seen some scenarios  
where the simple resource model doesn't capture what is going on and  
because the communications perspective *does* capture it. Also, while  
a service owner might not be a fundamental concept of the RM (it got  
voted down); it is still there for 99.99% of business owners :)
  The only negative I can see for the communications perspective is  
that it can be harder to grok.

Frank

On Oct 6, 2005, at 12:57 PM, Duane Nickull wrote:


> Let the flames begin....
>
> *******************************
> Adobe Systems, Inc. - http://www.adobe.com
> Vice Chair - UN/CEFACT
> Chair - OASIS SOA Reference Model Technical Committee
> *******************************
>
>
> <SOA-RM-Model-August2005.png>
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>