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)

The Flux API

Flux<T> is a general purpose reactive publisher. It represents a stream of asynchronous events with zero or more values, optionally terminated by either a completion signal or an error. It is important to note that a Flux emits the following three events:

  • Value refers to the values generated by the publisher
  • Completion refers to a normal termination of the stream
  • Error refers to an erroneous termination of the stream:

All of the preceding events are optional. This can lead to streams of the following types:

  • Infinite stream: A publisher generating only value events, and no terminal events (completion and error)
  • Infinite empty stream: A stream generating no value events and no terminating events
  • Finite stream: A publisher generating N finite values, followed by a terminal event
  • Empty stream: A publisher generating no value events, and only terminal events...