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

Understanding the problem domain

We start modeling the problem domain by considering the fact that a core router can connect to both core and edge routers. Edge routers, in turn, connect to switches and their networks. The following diagram depicts this scenario:

Figure 6.2 – A use case for the topology and inventory network system

Core routers are faster and deal with high traffic loads, and they don't deal directly with the traffic generated from a switch and its networks. On the other hand, edge routers deal directly with traffic generated by a switch and its networks. In our scenario, an edge router is not allowed to connect to other edge routers; it can only connect to core routers and switches. A switch can have multiple networks.

Bear in mind that's a particular arrangement established for our scenario. By no means does it represent a strict rule of how to organize network components. Here is a diagram showing the arrangement...