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Re: What is coupling? [Was: 3 XML Design Principles]

• To: "Bullard, Claude L (Len)" <len.bullard@i...>
• Subject: Re: What is coupling? [Was: 3 XML Design Principles]
• From: Robert Koberg <rob@k...>
• Date: Tue, 01 Feb 2005 11:00:11 -0800
• Cc: XML Developers List <xml-dev@l...>
• In-reply-to: <15725CF6AFE2F34DB8A5B4770B7334EE07206BAE@h...>
• References: <15725CF6AFE2F34DB8A5B4770B7334EE07206BAE@h...>
• User-agent: Mozilla Thunderbird 1.0 (Macintosh/20041206)

Bullard, Claude L (Len) wrote:
> Cohesion and coupling:
...
> and of course, the ultimate expression of homophilic principles, the Law of
> Demeter: 
> "Only talk to your friends."  For programmers, there are lots of articles on
> this one.
> 
> http://www.cmcrossroads.com/bradapp/docs/demeter-intro.html

I am having trouble applying OO to XML, but I read this from the above 
article:

"The Law of Demeter says that if I need to request a service of an 
objects sub-part, I should instead make the request of the object itself 
and let it propagate this request to all relevant sub-parts, thus the 
object is responsible for knowing its internal make-up instead of the 
method that uses it."

To me, if I have a nested structure in an XML instance and using XSL on 
that I apply-templates (flow through the instance doc) and only do what 
is in the XML. If I come across something that is a reference to 
something else I can go out, get it, apply-templates on it and continue 
where I left off.

If I have a flat structure in an instance doc I have to assume where 
things go and place them in a more rigid way.

Am I just not getting it?

-Rob

> 
> len
> 
> 
> 
> 
> 
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• References:
  • RE: What is coupling? [Was: 3 XML Design Principles]
    • From: "Bullard, Claude L (Len)" <len.bullard@i...>

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