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

Trunk-based development

Eric Evans, the inventor of DDD, talks about how continuous integration (CI) helps preserve the sanctity of the domain model within a bounded context. When more than one person works in the same bounded context, it tends to fragment. Obviously, the bigger the team, the higher the likelihood of this problem occurring. Even a team as small as three or four people can encounter serious issues. We have also seen that beyond a point, there may be diminishing returns if we try to break the system into extremely fine-grained bounded contexts.

This makes it very important to institute a process of merging/integrating all code and other implementation artifacts frequently, aided by automated tests to flag such fragmentation. In addition, this allows the team to apply the ubiquitous language relentlessly, each time refining the domain model to represent the problem more accurately. In other words, it is critical to practice continuous integration. Many teams make use...