Matthew Wells

One Minute Patterns GOF State

Wednesday, March 23rd, 2011

Here's the somewhat maligned GOF State Pattern. This allows us to localise state specific behaviour into a single subclass for each state. The State interface defines the behaviour that each concrete State class must implement. Here's a simple example. (We're all familiar with traffic lights!) That's it! What a state! Got ...

One Minute Patterns GOF Decorator

Monday, July 7th, 2008

OK, so lets start off with the GOF Decorator Pattern which allows us to extend functionality at runtime, without using inheritance. The Decorator object wraps the instance whose functionality it's enhancing, but implements the same interface as the original object. It delegates calls to the wrapped object, but ...

One Minute Patterns Introduction

Friday, July 4th, 2008

I was recently studying patterns for the Sun Certified Enterprise Architect for Java EE 5 exam and I realised that I was really only familiar with a small proportion of them.  I'd owned the seminal GOF Design Patterns book for 8 years and the Core J2EE Patterns book for five ...