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)

Sharing models between use cases

In Chapter 5, Implementing a Use Case, I argued that different use cases should have different input and output models, meaning that the types of the input parameters and the types of the return values should be different.

Figure 11.1 shows an example where two use cases share the same input model:

Figure 11.1 – Sharing the input or output model between use cases leads to coupling between the use cases

Figure 11.1 – Sharing the input or output model between use cases leads to coupling between the use cases

The effect of sharing in this case is that SendMoneyUseCase and RevokeActivityUseCase are coupled to each other. If we change something within the shared SendMoneyCommand class, both use cases are affected. They share a reason to change in terms of the Single Responsibility Principle (which should be named the “Single Reason to Change Principle,” as discussed in Chapter 3, Inverting Dependencies). The same is true if both use cases share the same output model.

Sharing input and output models between...