Clean Code Cookbook

Chapter 4. Primitive Obsession

The obsession with primitives is a primitive obsession.

Rich Hickey

4.0 Introduction

Many software engineers think that software is about “moving data around”; object-oriented schools and textbooks focus on the data and attributes when teaching about modeling the real world. This was a cultural bias taught in universities during the ’80s and ’90s. Industry trends pushed engineers to create entity-relationship diagrams (ERDs) and reason about the business data instead of focusing on the behavior.

Data is more relevant than ever. Data science is growing and the world revolves around data. You need to create a simulator to manage and protect data and expose behavior while hiding information and accidental representation to avoid coupling. The recipes from this chapter will help you identify small objects and hide accidental representation. You will discover many cohesive small objects and reuse them in many different contexts.

Cohesion

Cohesion is a measure of the degree to which the elements within a single software class or module work together to achieve a single, well-defined purpose. It refers to how closely related the objects are to each other and to the overall goal of the module. You can see high cohesion as a desirable property in software design since the elements within a module are closely related and work together effectively to achieve a specific goal.

4.1 Creating Small Objects

Problem

You have big objects containing only primitive ...