I do not think I said anything about objects being "bad" for implementing 
services, nor would I say so.  They are a completely valid option.  

But an object is not a service, even though a service can be implemented using 
one.  And therefore it's bad or any counterproductive to think of the world in 
terms of "things" that maps to objects, instead of as "functions" that map to 
services.

A service is not a subset of an object, either, as some would say.  The concept 
of a service predates the concept of an object and is more abstract.  

A good test is to ensure that a service design could be implemented using an 
object, a message queue, a procedure, stored procedure, database query, script, 
etc.  If the service design can only be implemented using an object then the 
benefit of the abstraction is lost.

To me this is a conceptual problem, and a modeling problem, not an 
implementation issue.  People are so used to thinking about software systems in 
terms of objects that they often misunderstand services.  Some folks prefer to 
draw parallels but I prefer to highlight differences since so many people tend 
to equate the two.

This is why UML and MDA are not well suited for Web services, by the way, since 
their design center is the class diagram.

Eric


----- Original Message ----
From: Gregg Wonderly <[EMAIL PROTECTED]>
To: [email protected]
Sent: Thursday, February 8, 2007 12:53:42 AM
Subject: Re: [service-orientated-architecture] Booch on SOA & Architecture

Eric Newcomer wrote:
> Obviously someone who can't give up objects in favor of services.

Humm, does that mean that a service can never be an object, but must be 
multiple 
objects or multiple of something? I agree that all "services" in an SOA may not 
be software services, but for software based services, what makes it bad for 
them to be objects in implementation?

Gregg Wonderly




 
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