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

Invocation style

When integrating two bounded contexts that are running in distinct processes, there are two ways to consummate interactions: synchronous and asynchronous.

Synchronous invocation

The client blocks until the server provides a response. Optionally, implementations can choose to wait for an amount of time for the invoked operation to complete before timing out. An example of such an interaction is a blocking HTTP call made to start a new LC application like so:

Figure 12.4 – Synchronous invocation

When the call returns successfully, the client is sure that their request to create a new LC application has worked. If the server is slow to respond, it can result in a performance bottleneck, especially in high-scale scenarios. To cope with this, the client and the server may agree on a response time SLO for that interaction. The client can choose to wait for a response from the server for the agreed amount of time after which the client...