Book Image

Domain-Driven Design with Java - A Practitioner’s Guide

By : Premanand Chandrasekaran, Karthik Krishnan
Book Image

Domain-Driven Design with Java - A Practitioner’s Guide

By: Premanand Chandrasekaran, Karthik Krishnan

Overview of this book

Domain-Driven Design (DDD) makes available a set of techniques and patterns that enable domain experts, architects, and developers to work together to decompose complex business problems into a set of well-factored, collaborating, and loosely coupled subsystems. This practical guide will help you as a developer and architect to put your knowledge to work in order to create elegant software designs that are enjoyable to work with and easy to reason about. You'll begin with an introduction to the concepts of domain-driven design and discover various ways to apply them in real-world scenarios. You'll also appreciate how DDD is extremely relevant when creating cloud native solutions that employ modern techniques such as event-driven microservices and fine-grained architectures. As you advance through the chapters, you'll get acquainted with core DDD’s strategic design concepts such as the ubiquitous language, context maps, bounded contexts, and tactical design elements like aggregates and domain models and events. You'll understand how to apply modern, lightweight modeling techniques such as business value canvas, Wardley mapping, domain storytelling, and event storming, while also learning how to test-drive the system to create solutions that exhibit high degrees of internal quality. By the end of this software design book, you'll be able to architect, design, and implement robust, resilient, and performant distributed software solutions.
Table of Contents (17 chapters)
Part 1: Foundations
Part 2: Real-World DDD
Part 3: Evolution Patterns

Chapter 1: The Rationale for Domain-Driven Design

The being cannot be termed rational or virtuous, who obeys any authority, but that of reason.

— Mary Wollstonecraft

According to the Project Management Institute’s (PMI’s) Pulse of the Profession report published in February 2020, only 77% of all projects meet their intended goals—and even this is true only in the most mature organizations. For less mature organizations, this number falls to just 56%; that is, approximately one in every two projects does not meet its intended goals. Furthermore, approximately one in every five projects is declared an outright failure. At the same time, we also seem to be embarking on our most ambitious and complex projects.

In this chapter, we will examine the main causes of project failure and look at how applying domain-driven design (DDD) provides a set of guidelines and techniques to improve the odds of success in our favor. While Eric Evans wrote his classic book on the subject way back in 2003, we look at why that work is still extremely relevant in today’s times.

In this chapter, we will cover the following topics:

  • Understanding why software projects fail
  • Characteristics of modern systems and dealing with complexity
  • Introduction to DDD
  • Reviewing why DDD is relevant today

By the end of this chapter, you will have gained a basic understanding of DDD and why you should strongly consider applying the tenets of DDD when architecting/implementing modern software applications, especially the more complex ones.