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)

Different Output Models for Different Use Cases

Once the use case has done its work, what should it return to the caller?

Similar to the input, it has benefits if the output is as specific to the use case as possible. The output should only include the data that is really needed for the caller to work.

In the preceding example code of the "Send Money" use case, we returned a boolean. This is the minimal and most specific value we could possibly return in this context.

We might be tempted to return a complete Account with the updated entity to the caller. Perhaps the caller is interested in the new balance of the account.

But do we really want to make the "Send Money" use case return this data? Does the caller really need it? If so, shouldn't we create a dedicated use case for accessing that data that can be used by different callers?

There is no right answer to these questions. But we should ask them to try to keep our use cases as specific as possible. When in doubt...