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)

Skipping Application Services

Aside from the incoming ports, for certain use cases, we might want to skip the application layer as a whole, as shown in the following figure:

Figure 11.4: Without application services, we don't have a specified location for domain logic

Here, the AccountPersistenceAdapter class within an outgoing adapter directly implements an incoming port and replaces the application service that usually implements an incoming port.

It is very tempting to do this for simple CRUD use cases, since in this case an application service usually only forwards a create, update, or delete request to the persistence adapter, without adding any domain logic. Instead of forwarding, we can let the persistence adapter implement the use case directly.

This, however, requires a shared model between the incoming adapter and the outgoing adapter, which is the Account domain entity in this case, so it usually means that we are using the domain model as the input model as described...