blairanderson

Dependency Injection in Ruby 07 Oct 04

Introduction

At the 2004 Ruby Conference, Jamis Buck had the unenviable task to explain Dependency Injection to a bunch of Ruby developers. First of all, Dependency Injection (DI) and Inversion of Control (IoC) is hard to explain, the benefits are subtle and the dynamic nature of Ruby make those benefits even more marginal. Furthermore examples using DI/IoC are either too simple (and don’t convey the usefulness) or too complex (and difficult to explain in the space of an article or presentation). I once attempted to explain DI/IoC to a room of Java programmers (see onestepback.org/articles/dependencyinjection/), so I can’t pass up trying to explain it to Ruby developers.

Thanks goes to Jamis Buck (the author of the Copland DI/IoC framework) who took the time to review this article and provide feedback.

What is Dependency Injection?

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

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This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

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speric

Chapter 1 - Object Oriented Design

The purpose of design is to allow you to do design later, and it's primary goal is to reduce the cost of change.

SOLID Design:

• Single Responsibility Principle: a class should have only a single responsibility
• Open-Closed Principle: Software entities should be open for extension, but closed for modification (inherit instead of modifying existing classes).
• Liskov Substitution: Objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.
• Interface Segregation: Many client-specific interfaces are better than one general-purpose interface.