Book Image

Designing Hexagonal Architecture with Java

By : Davi Vieira
Book Image

Designing Hexagonal Architecture with Java

By: Davi Vieira

Overview of this book

Hexagonal architecture enhances developers' productivity by decoupling business code from technology code, making the software more change-tolerant, and allowing it to evolve and incorporate new technologies without the need for significant refactoring. By adhering to hexagonal principles, you can structure your software in a way that reduces the effort required to understand and maintain the code. This book starts with an in-depth analysis of hexagonal architecture's building blocks, such as entities, use cases, ports, and adapters. You'll learn how to assemble business code in the Domain hexagon, create features by using ports and use cases in the Application hexagon, and make your software compatible with different technologies by employing adapters in the Framework hexagon. Moving on, you'll get your hands dirty developing a system based on a real-world scenario applying all the hexagonal architecture's building blocks. By creating a hexagonal system, you'll also understand how you can use Java modules to reinforce dependency inversion and ensure the isolation of each hexagon in the architecture. Finally, you'll get to grips with using Quarkus to turn your hexagonal application into a cloud-native system. By the end of this hexagonal architecture book, you'll be able to bring order and sanity to the development of complex and long-lasting applications.
Table of Contents (21 chapters)
1
Section 1: Architecture Fundamentals
7
Section 2: Using Hexagons to Create a Solid Foundation
12
Section 3: Becoming Cloud-Native

Transforming ports, use cases, and adapters into CDI beans

When designing the Application hexagon for the topology and inventory system, we defined the use cases as interfaces and input ports as their implementations. We also defined output ports as interfaces and output adapters as their implementations in the Framework hexagon. In this section, we'll refactor components from both the Application and Framework hexagons to enable the usage of dependency injection with Quarkus DI.

The first step to working with Quarkus DI is to add the following Maven dependency to the project's root pom.xml file:

<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-resteasy</artifactId>
</dependency>

In addition to the RESTEasy libraries, this quarkus-resteasy library also provides the required libraries to work with Quarkus DI.

Let's start our refactoring efforts with the classes and interfaces related...