Book Image

Hands-On Reactive Programming with Reactor

By : Rahul Sharma
Book Image

Hands-On Reactive Programming with Reactor

By: Rahul Sharma

Overview of this book

Reactor is an implementation of the Java 9 Reactive Streams specification, an API for asynchronous data processing. This specification is based on a reactive programming paradigm, enabling developers to build enterprise-grade, robust applications with reduced complexity and in less time. Hands-On Reactive Programming with Reactor shows you how Reactor works, as well as how to use it to develop reactive applications in Java. The book begins with the fundamentals of Reactor and the role it plays in building effective applications. You will learn how to build fully non-blocking applications and will later be guided by the Publisher and Subscriber APIs. You will gain an understanding how to use two reactive composable APIs, Flux and Mono, which are used extensively to implement Reactive Extensions. All of these components are combined using various operations to build a complete solution. In addition to this, you will get to grips with the Flow API and understand backpressure in order to control overruns. You will also study the use of Spring WebFlux, an extension of the Reactor framework for building microservices. By the end of the book, you will have gained enough confidence to build reactive and scalable microservices.
Table of Contents (13 chapters)

Chapter 10: Testing and Debugging

  1. Which test utility class is available in Reactor to validate the invoked operations on a stream?

Reactor provides the StepVerifier component to validate the required operations in isolation.

  1. What is the difference between PublisherProbe and TestPublisher?

The PublisherProbe utility can instrument an existing publisher. The probe keeps track of signals published by the publisher, which can be validated at the end of the test. On the other hand, TestPublisher is capable of generating the Publisher stub, which can be used to unit test Reactor operators.

  1. How should the virtual clock be configured to validate time-bound operations ?

The virtual clock must be injected before performing any time-based operations.

  1. What is the difference between the onOperatorDebug hook and the checkpoint operator?

The onOperatorDebug hook makes a global change...