Re: What's a pattern?

From:
=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 05 Aug 2009 17:38:49 -0400
Message-ID:
<4a79fbe3$0$308$14726298@news.sunsite.dk>
Jan Paulsen wrote:

I'm getting a bit philosophical here, please point me towards a better
newsgroup if I'm too much off-topic.

Anyway, I bet the subject got your attention. Perhaps reading on will
help justify the title.

Recently, I read a post in this newsgroup describing the "select"
technique as a pattern. In case you need a reminder, the "select"
technique is based on a statement of the same name in which you give a
number of channels and the result of the statement is the result of
reading a message from the first channel. The technique is nothing
special to Java, but can also be find e.g. in functional languages.

This led me to wonder a bit about our usage of the word "pattern", which
I would very much like your input about.

Besides the common notion of a "pattern", there are more academically
precise notions. There's the GoF book describing design patterns,
Alexander gave the origins to the paradigm in his seminal work on
architectural patterns, Lynn and Manns gave an introduction to the
personal leadership of change using patterns, we have even learned about
anti-patterns in analysis and no doubt I have forgotten some important
works.

However, it seems to me that common use, as was the case of the post
mentioned in the beginning of this article, is that almost everything is
regarded as a "pattern" if there's some repetitive nature to the
observation.

So, are we starting to use the common notion rather than the
academically precise and well-researched definitions? That is, do you
often say to your colleges that "I have this pattern in my code" where
you are not referring to a well-defined pattern, but to some custom or,
as I call it, technique? Are you, sitting in the canteen, telling about
"patterns" in your methodology when you cannot pinpoint the origin of
the pattern you are talking about? Or do you see some other uses of the
term "pattern" when it is not well-defined?

Again, sorry if I'm off-topic, just started to wonder.


I don't see much difference between academic and common use
of the word.

Both see it as "a recommended solution for a specific problem".

A difference in level of documentation does not imply a
difference in opinion.

And it is hardly surprising that someone writing a book
about patterns document them better than a team trying
to deliver a web app on time and on budget.

Arne

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