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)

Visibility modifiers

Let’s start with the most basic tool that object-oriented languages in general, and Java in particular, provide us with to enforce boundaries: visibility modifiers.

Visibility modifiers have been a topic in almost every entry-level job interview I have conducted in the last couple of years. I would ask the interviewee which visibility modifiers Java provides and what their differences are.

Most of the interviewees only list the public, protected, and private modifiers. Only a few of them know the package-private (or default) modifier. This is always a welcome opportunity for me to ask some questions about why such a visibility modifier would make sense in order to find out whether the interviewee can abstract from their previous knowledge.

So, why is the package-private modifier such an important modifier? Because it allows us to use Java packages to group classes into cohesive “modules.” Classes within such a module can access each...