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

Where to draw the line

In general, the smaller the size of our bounded contexts, the easier it becomes to manage complexity. Does that mean we should decompose our systems into as fine-grained a granularity as possible? On the other hand, having extremely fine-grained components can increase coupling among them to the extent where it becomes very hard to manage operational complexity. Hence, decomposing a system into well-factored, collaborating components can be a bit tricky, seeming to work more like an art rather than an exact science. There is no right or wrong answer here. In general, if things feel and become painful, you most likely got it more wrong than right. Here are some non-technical heuristics that might help guide this process:

  • Existing organization boundaries: Look to align along with current organizational structures. Identify which applications your business unit/department/team already owns and assign responsibilities in a manner that causes minimal disruption...