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)

An Architecturally Expressive Package Structure

In a hexagonal architecture, we have entities, use cases, incoming and outgoing ports, and incoming and outgoing (or "driving" and "driven") adapters as our main architectural elements. Let's fit them into a package structure that expresses this architecture:

Figure 3.3: In an architecturally expressive package structure, each architecture element has its place

Each element of the architecture can directly be mapped to one of the packages. At the highest level, we again have a package named account, indicating that this is the module implementing the use cases around an Account.

On the next level, we have the domain package containing our domain model. The application package contains a service layer around this domain model. SendMoneyService implements the incoming port interface, SendMoneyUseCase, and uses the outgoing port interfaces, LoadAccountPort and UpdateAccountStatePort, which are implemented by...