Book Image

Get Your Hands Dirty on Clean Architecture

By : Tom Hombergs
Book Image

Get Your Hands Dirty on Clean Architecture

By: Tom Hombergs

Overview of this book

Building for maintainability is key to keeping development costs low and processes easy. The second edition of Get Your Hands Dirty on Clean Architecture is here to equip you with the essential skills and knowledge to build maintainable software. With this comprehensive guide, you’ll explore the drawbacks of conventional layered architecture and the advantages of domain-centric styles such as Robert C. Martin's Clean Architecture and Alistair Cockburn's Hexagonal Architecture. Then, you’ll dive into hands-on explanations on how to convert hexagonal architecture into actual code. You'll learn in detail about different mapping strategies between the layers of hexagonal architecture and discover how to assemble the architectural elements into an application. Additionally, you’ll understand how to enforce architecture boundaries, which shortcuts produce what types of technical debt, and how, sometimes, it is a good idea to willingly take on those debts. By the end of this second edition, you'll be armed with a deep understanding of the hexagonal architecture style and be ready to create maintainable web applications that save money and time.
Table of Contents (13 chapters)

Inverting Dependencies

After the rant about layered architecture in the previous chapter, you are right to expect this chapter to discuss an alternative approach. We will start by discussing the Single Responsibility Principle and the Dependency Inversion Principle. They are the "S" and the "D" of the SOLID principles, which you can read about in detail in "Clean Architecture" by Robert C. Martin or on Wikipedia at

The Single Responsibility Principle

Everyone in software development probably knows the Single Responsibility Principle (SRP) or at least assumes they know it.

A common interpretation of this principle is this:

A component should do only one thing, and do it right.

That's good advice, but not the actual intention of the SRP.

"Doing only one thing" is actually the most obvious interpretation of a single responsibility, so it's no wonder that the SRP is frequently interpreted...