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)

The "Two-Way" Mapping Strategy

A mapping strategy where each layer has its own model is what I call the "two-way" mapping strategy, outlined in the following figure:

Figure 8.2: With each adapter having its own model, the adapters are responsible for mapping their model into the domain model and back

Each layer has its own model, which may have a structure that is completely different from the domain model.

The web layer maps the web model into the domain model that is expected by the incoming ports. It also maps domain objects returned by the incoming ports back into the web model.

The persistence layer is responsible for a similar mapping between the domain model, which is used by the outgoing ports, and the persistence model.

Both layers map in two directions, hence the name "two-way" mapping.

With each layer having its own model, each layer can modify its own model without affecting the other layers (as long as the contents are unchanged). The web...