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Reducing complexity

From: Mark Baker <distobj@acm.org>
Date: Wed, 20 Nov 2002 22:18:31 -0500
To: "Champion, Mike" <Mike.Champion@SoftwareAG-USA.com>
Cc: www-ws-arch@w3.org
Message-ID: <20021120221831.P21537@www.markbaker.ca>

On Wed, Nov 20, 2002 at 01:23:28PM -0700, Champion, Mike wrote:
> > I think that interface simplification/unification only gives 
> > you a false sense of complexity reduction. The complexity 
> > (both syntax and semantics) that you remove from the 
> > interface you will find in different form in other places, 
> > like the document contents transmitted through the REST 
> > unified interface, or the choreography computations which 
> > depend both on the data itself and on other external factors. 
> > So the total complexity of non trivial real world system 
> > interconnections is always far from O(N).
> 
> +1  That's what I was trying to say :-)  The "conservation
> of complexity" principle across code and data.

With or without a uniform or a specific interface, the problem breaks
down into dealing with an interface, then dealing with what the
interface gives you.  As an example of how this looks, consider the
interfaces that Dan talks about in issue 5[1] raised by this[2] email.

One is;

interface StockQuote {
  Document GetLastTradePrice( String symbol );
}

and the other implicit one that he's suggesting by using GET is;

interface StockQuoteLastTradePrice {
  Document GET();
}

The same data can be returned in both cases.  But complexity *has* been
reduced in the latter example, by virtue of the relationship between an
identifier for a service, and the GET method.  You need less
information, because with the former example, given an identifier of
that service, you also need to know which method to use to ask it to
give you the goods.  But the complexity of handling the data is
identical.  Net, complexity is reduced.

 [1] http://www.w3.org/2002/ws/arch/2/issues/wsa-issues.html#x5
 [2] http://lists.w3.org/Archives/Public/www-wsa-comments/2002Jun/0003

MB
-- 
Mark Baker.  Ottawa, Ontario, CANADA.   http://www.markbaker.ca

   Will distribute objects for food
Received on Wednesday, 20 November 2002 22:14:56 GMT

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