RE: [soa-rm] Revisiting: Definition of Service Orientation and how it relates to SOA

["Smith, Martin" <Martin.Smith@DHS.GOV>]

Ken- - Agree that these are characteristics of SOA, but I'd say that they are mostly not DISTINGUISHING characteristics.  Modularity and re-use and interchangeability/standards are themes that have been developed over a long period of time.  OO certainly promotes both.  So does component-based AD. SOA incorporates tehse principles, for sure.   
 
But what's the difference between component-based AD and services-oriented AD?  What does SOA add to CBD?
 
Martin
 

________________________________

From: Ken Laskey [mailto:klaskey@mitre.org]
Sent: Thu 5/26/2005 6:04 PM
To: soa-rm@lists.oasis-open.org
Subject: Re: [soa-rm] Revisiting: Definition of Service Orientation and how it relates to SOA



... snip

For more flexibility, I don't just want one service to take the 
undesirable work off my hands, I want a choice.  And because I know 
that my choice may change depending on circumstances, I want to 
dynamically make the choice.  (Don't you hate it when you get a wedding 
invitation and you have to decide what you want to eat a month from 
now?)  Or even if not with zero latency, I want to be able to easily 
change my choice. I need services to be interchangeable.

And I don't want my choice to lock me into a whole set of other 
choices.  I go to buy a car and I want airbags but I can only get these 
if I get power windows!  I want an interoperability of my choices along 
with interchangeability of parts that I choose.

Finally, what is the polar opposite of services?  The polar opposite is 
NIH, not invented here.  Service orientation says I want to do as 
little by myself as possible.  There are people out there who are 
smarter than me and do some things better than me and I'm going to make 
use of that expertise whenever I can.  That takes a certain level of 
trust because I am giving up control of the details so I can spend my 
energy on the things I can best provide to others.  The opposite is 
assuming everything I need to do is unique and no one can do any of it 
as well as me (or as well as someone I would directly control).  Now 
when you have opposites, you usually have degrees between them.