The Art of Agile Development, 2nd Edition

Simple Design

AUDIENCE

Programmers

Our code is easy to modify and maintain.

Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

Antoine de Saint-Exupéry, author of The Little Prince

When writing code, Agile programmers often stop to ask themselves, “What’s the simplest thing that could possibly work?” They seem to be obsessed with simplicity. Rather than anticipating changes and providing extensibility hooks and plug-in points, they create a simple design that anticipates as little as possible, as cleanly as possible. Counterintuitively, this results in designs that are ready for any change, anticipated or not. It combines with reflective design and incremental design to allow your design to evolve in any direction.

Simple doesn’t mean simplistic. Don’t make boneheaded design decisions in the name of reducing lines of code. A simple design is clean and elegant, not something you throw together with the least thought possible. Whenever I make a design decision, I always ask myself this question: “When, not if, I need to change this decision, how hard will it be?”

The following techniques will help you keep your code simple and change costs low.

SIMPLICITY

Simplicity—the art of maximizing the amount of work not done—is essential.

Manifesto for Agile Software Development

Agile is the result of embracing simplicity. It’s not just for software design; it’s for all aspects of your work. How can big, heavyweight processes be ...