Appendix: Musings on Design Patterns

Capturing hard-won software design experience in the form of design patterns and architectural patterns is a noble cause that everyone can contribute to.

You can contribute by writing patterns and maybe even coming to a Plop patterns conference.

Basically when you see a software development technique a few times, and see that it isn’t yet documented - write it up in Pattern format and give it a name!

A pattern is more than just a “tip” or technique though - a pattern represents an abstract idea - that can be implemented in various ways depending on your circumstances.

The Patterns Movement

The Patterns Movement is spearheaded by Hillside and the Plop conferences, held each year.

There are a couple of things I would like to see happen in the patterns world.

• First, it would be nice if there was a single, authoritative repository of patterns. Yes an attempt has been made - a catalog book and and various websites - but nothing authoratative. I started a list of links here.

• Secondly, it would be nice to have deep design pattern support in UML within all our favourite IDE’s. For example Netbeans has it all - coding, form design, UML and design pattern support - albiet not as integrated as it could be and not as polished as it could be. Update: Unfortunately Netbeans seems to have dropped UML support in recent builds.

Comments indicating Pattern usage

If IDE’s are not your cup of tea, then how about this: source code should have comment markers indicating where the patterns are, so that a reverse engineering tool can visualise not only the UML but also where the patterns are.

My own UML tool PyNSource will have such a feature - est. June 2011 (turns out this never happened :-).

Executable UML

Further advancements are arguably executable UML and even the possibility of building software without code. I muse a bit about this in my blog entry on software visualisation and my paper on design pattern tools. 

A repository of patterns

First, it would be nice if there was a single, authoritative repository of patterns. Yes an attempt has been made - a catalog book and and various websites - but nothing authoratative.  I’m starting a list of links here.

Patterns at all levels need to be core visual building blocks of IDE’s, or at the very least, extractable from source code into some visual UML tool - rather than being design ghosts that float around, implicit, in our source code.