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

Continuous testing

In an ideal world, continuous integration will enable us to adopt continuous testing, which provides us with constant and early feedback. This is essential because our bounded contexts and the resulting domain models are in a constant state of evolution. Without the bedrock of a stable suite of tests, it can become very hard to sustain a reliable process. Approaches such as the test pyramid, testing trophy, honeycomb, and so on are acknowledged as reasonable ways to implement a sound continuous testing strategy. All of these approaches are based on the premise that a large number of cheap (computationally and cognitively) unit tests form the foundation of the strategy, with the number of tests in other categories (service, UI, manual, and so on) reducing as we move through the chain.

However, we are in this new world of fine-grained components that work by communicating with each other. Hence, there is a bigger need to verify interactions at the periphery in a...