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

Performance and scale

In previous chapters, we saw how it is possible and sometimes even necessary to break functionality down into fine-grained components that are physically separated from each other – requiring a network to collaborate. Let’s assume that this collaboration is achieved in a loosely coupled manner – justifying the need for disparate bounded contexts from a logical perspective.

Performance is a very important SLO that is typically associated with most applications. When it comes to performance, it is essential to understand the basic terms. This is best illustrated using an example as shown here:

Figure 12.1 – The elements of network performance

As shown here, the following terms are relevant in the context of performance:

  • Latency: The delay introduced by the network (A + B)
  • Response Time: the total time taken by the system to respond to the user (A + B + C)
  • Bandwidth: The maximum capacity of...