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 “One-Way” mapping strategy

There is yet another mapping strategy with another set of pros and cons: the “One-Way” strategy visualized in Figure 9.4.

Figure 9.4 – With the domain model and the adapter models implementing the same “state” interface, each layer only needs to map objects it receives from other layers one way

Figure 9.4 – With the domain model and the adapter models implementing the same “state” interface, each layer only needs to map objects it receives from other layers one way

In this strategy, the models in all layers implement the same interface, which encapsulates the state of the domain model by providing getter methods on the relevant attributes.

The domain model itself can implement a rich behavior, which we can access from our services within the application layer. If we want to pass a domain object to the outer layers, we can do so without mapping since the domain object implements the state interface expected by the incoming and outgoing ports.

The outer layers can then decide whether they can work with the interface or whether they need to...