Preface

Reactive systems are responsive at all times, which is what most businesses demand. The development of such systems is a complex task and requires a deep understanding of the domain. Fortunately, developers of the Spring Framework have created a new, reactive version of the project.

With Reactive Programming in Spring 5, you'll explore the fascinating process of developing a Reactive system using Spring Framework 5.

This book begins with the foundation of Spring Reactive programming. You will gain an understanding of the possibilities of the framework and learn about the fundamentals of reactivity. Further on, you will study the techniques of reactive programming, learn how to apply them to databases, and use them for cross-server communication. All of these tasks will be applied to a real project example, which will enable you to practice the skills learned.

Get on board with the reactive revolution in Spring 5!

Who this book is for

This book is for Java developers who use Spring to develop their applications and want to be able to build robust and reactive applications that can scale in the cloud. Basic knowledge of distributed systems and asynchronous programming is assumed.

What this book covers

Chapter 1, Why Reactive Spring?, covers the business cases in which reactivity fits very well. You will see why a reactive solution is better than a proactive one. Also, you will get an overview of a few code examples that show different ways of cross-server communication, as well as an understanding of today's business needs and their requirements of the modern Spring Framework.

Chapter 2, Reactive Programming in Spring - Basic Concepts, expands on the potential of reactive programming and its central concepts by means of code examples. The chapter then shows the power of reactive, asynchronous, non-blocking programming in the Spring Framework with code examples, and applies this technique in business cases. You'll garner an overview of the publisher-subscriber model in examples of code, understand the power of reactive Flow events, and learn about the application of these techniques in real-world scenarios.

Chapter 3, Reactive Streams - the New Streams' Standard, concentrates on the problems that are introduced by Reactive Extensions. Code examples are used to explore the different approaches and expand upon the nature of the problems. The chapter also delves into problem-solving and the introduction of the Reactive Streams specification, which introduces new components to the well-known publisher-subscriber model.

Chapter 4, Project Reactor - the Foundation for Reactive Apps, looks at the realization of the reactive library; that is, fully implementing the Reactive Streams specification. Firstly, this chapter emphasizes the advantages of implementing Reactor, and then it takes a survey of the reasons that motivated Spring developers to develop their own new solution. Also, this chapter embraces the fundamentals of this impressive library—here you'll get an understanding of Mono and Flux, as well as the applications for reactive types.

Chapter 5, Going Reactive with Spring Boot 2, introduces the Spring 5 reactive modules required for reactive application development. Here you'll learn how to get started with modules, and how Spring Boot 2 helps developers configure applications fast.

Chapter 6, WebFlux Async Non-Blocking Communication, covers the primary module, Spring WebFlux, which is the essential tool for the organization of asynchronous, non-blocking communication with both the user and external services. This chapter gives an overview of the advantages of this module and the comparison with Spring MVC.

Chapter 7, Reactive Database Access, goes into the Spring 5-based reactive programming model for data access. This chapter's emphasis is upon reactive reinforcement in Spring Data modules and explores the features that come out of the box with Spring 5, Reactive Streams, and Project Reactor. In this chapter, you will encounter code that shows a reactive approach for communication with different databases, such as SQL and NoSQL databases.

Chapter 8, Scaling Up with Cloud Streams, will introduce you to the reactive features of Spring Cloud Streams. Before starting to learn about the new brilliant capabilities of the module, you'll be given an overview of business case gaps and the problems that you can be faced with when scaling on different servers. This chapter reveals to you the power of the Spring Cloud solution, covering its implementation via code examples of the relevant Spring Boot 2 configuration.

Chapter 9, Testing the Reactive Application, covers the basics required for reactive pipeline testing. This chapter introduces the Spring 5 Test and Project Reactor Test modules for writing tests. Here you will see how to manipulate the frequency of events, move timelines, enhance thread pools, mock results, and assert passed messages.

Chapter 10, And, Finally, Release It!, is a step-by-step guide to current solution deployment and monitoring. Here you will see how to monitoring reactive microservices, for which Spring 5 modules are required. Also, the chapter covers the tools that will be useful for monitoring the aggregation and display of results.

To get the most out of this book

The development of reactive systems is a complex task, requiring a deep understanding of the domain. A knowledge of distributed systems and asynchronous programming is required.

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