Design Patterns study group

A new thing at Eden is we have started a study group and we are currently studying the Gang of Four Design Patterns book. I’ve read this before but i’ve not studied it. I guess i got an overview and thought to myself, “Well, i know where to look if i ever want to look up a pattern …” – Have i ever looked up a pattern since? No! ;)

So i’m really glad to be studying it this time and really getting to know the patterns properly so that i can use them readily whenever appropriate. It’s good to have the opportunity to discuss one pattern at a time in a group. Here’s a photo from the first study group last week:

Design Patterns Study Group

As part of my studying, i am implementing examples of the patterns in Ruby. Last week i coded the Factory Method example. It’s funny how i can skim over the code in the book and convince myself that i understand it, but coming to implement it for myself in a different language was a challenge. One that i thoroughly enjoyed, i have to say! :) I’m happy to say that i now fully understand the factory method!

I’ve also been writing tests to ensure the code works as i expect. This has been useful because i’ve learned about Test::Unit which was previously unknown to me. When i joined Eden i learned RSpec and Cucumber (or story_runner or whatever it was called back then). Other than that i’d never tested Ruby before.

This week i have been implementing sorting algorithms as strategies. I wasn’t too impressed with the code examples in the book for the Strategy pattern, largely because they left out all the code that actually differs between the strategies! So i decided to make up my own example. It has been good to refresh my memory on sorting algorithms at the same time as clarifying how the Strategy pattern works.

You can follow along with my workings on sermoa/ruby_design_patterns.