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)

Rich versus Anemic Domain Model

Our architecture style leaves open how to implement our domain model. This is a blessing because we can do what seems right in our context, and a curse because we don't have any guidelines to help us.

A frequent discussion is whether to implement a rich domain model following the DDD philosophy or an "anemic" domain model. I'm not going to favor one of the two, but let's discuss how each of them fits into our architecture.

In a rich domain model, as much of the domain logic as possible is implemented within the entities at the core of the application. The entities provide methods to change state and only allow changes that are valid according to the business rules. This is the way we pursued with the Account entity previously.

Where is our use case implementation in this scenario?

In this case, our use case serves as an entry point to the domain model. A use case then only represents the intent of the user and translates it into orchestrated...