Book Image

Designing Hexagonal Architecture with Java - Second Edition

By : Davi Vieira
Book Image

Designing Hexagonal Architecture with Java - Second Edition

By: Davi Vieira

Overview of this book

We live in a fast-evolving world with new technologies emerging every day, where enterprises are constantly changing in an unending quest to be more profitable. So, the question arises — how to develop software capable of handling a high level of unpredictability. With this question in mind, this book explores how the hexagonal architecture can help build robust, change-tolerable, maintainable, and cloud-native applications that can meet the needs of enterprises seeking to increase their profits while dealing with uncertainties. This book starts by uncovering the secrets of the 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 with ports and use cases in the application hexagon, and make your software compatible with different technologies by employing adapters in the framework hexagon. In this new edition, you’ll learn about the differences between a hexagonal and layered architecture and how to apply SOLID principles while developing a hexagonal system based on a real-world scenario. Finally, you’ll get to grips with using Quarkus to turn your hexagonal application into a cloud-native system. By the end of this book, you’ll be able to develop robust, flexible, and maintainable systems that will stand the test of time.
Table of Contents (24 chapters)
1
Part 1: Architecture Fundamentals
7
Part 2: Using Hexagons to Create a Solid Foundation
12
Part 3: Becoming Cloud-Native
18
Part 4: Hexagonal Architecture and Beyond

Conventions used

There are a number of text conventions used throughout this book.

Code in text: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: “Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system.”

A block of code is set as follows:

public interface RouterNetworkUseCase {
    Router addNetworkToRouter(RouterId,
    Network network);
    Router getRouter(RouterId routerId);
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

function getRouter() {
    const routerId = document.
    getElementById("routerId").value;
    var xhttp = new XMLHttpRequest();
    xhttp.onreadystatechange = function() {
        console.log(this.responseText);
        if (this.readyState == 4 && this.status == 200) {
            const json = JSON.parse(this.responseText)
            createTree(json)
        }

Any command-line input or output is written as follows:

java -jar target/topology-inventory-1.0-SNAPSHOT-jar-with-dependencies.jar rest
REST endpoint listening on port 8080...
Topology & Inventory WebSocket started on port 8887...

Bold: Indicates a new term, an important word, or words that you see onscreen. For instance, words in menus or dialog boxes appear in bold. Here is an example: “Select System info from the Administration panel.”

Tips or important notes

Appear like this.