Book Image

Get Your Hands Dirty on Clean Architecture - Second Edition

By : Tom Hombergs
4 (1)
Book Image

Get Your Hands Dirty on Clean Architecture - Second Edition

4 (1)
By: Tom Hombergs

Overview of this book

Building for maintainability is key to keep development costs low (and developers happy). 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. Building upon the success of the first edition, this comprehensive guide explores the drawbacks of conventional layered architecture and highlights the advantages of domain-centric styles such as Robert C. Martin's Clean Architecture and Alistair Cockburn's Hexagonal Architecture. Then, the book dives into hands-on chapters that show you how to manifest a Hexagonal Architecture in actual code. You'll learn in detail about different mapping strategies between the layers of a Hexagonal Architecture and see how to assemble the architecture elements into an application. The later chapters demonstrate how to enforce architecture boundaries, what 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. Whether you're a seasoned developer or a newcomer to the field, "Get Your Hands Dirty on Clean Architecture" will empower you to take your software architecture skills to new heights and build applications that stand the test of time.
Table of Contents (18 chapters)

The role of dependency injection

The package structure described previously goes a long way toward achieving a clean architecture, but an essential requirement of such an architecture is that the application layer does not have dependencies on the incoming and outgoing adapters, as we have learned in Chapter 3, Inverting Dependencies.

For incoming adapters, such as our web adapter, this is easy since the control flow points in the same direction as the dependency between the adapter and the domain code. The adapter simply calls the service within the application layer. In order to clearly bring out the entry points to our application, we’ll want to hide the actual services behind port interfaces.

For outgoing adapters, such as our persistence adapter, we have to make use of the Dependency Inversion Principle to turn the dependency against the direction of the control flow.

We have already seen how that works. We create an interface within the application layer, which...