Book Image

Learning RxJava

By : Thomas Nield
Book Image

Learning RxJava

By: Thomas Nield

Overview of this book

RxJava is a library for composing asynchronous and event-based programs using Observable sequences for the JVM, allowing developers to build robust applications in less time. Learning RxJava addresses all the fundamentals of reactive programming to help readers write reactive code, as well as teach them an effective approach to designing and implementing reactive libraries and applications. Starting with a brief introduction to reactive programming concepts, there is an overview of Observables and Observers, the core components of RxJava, and how to combine different streams of data and events together. You will also learn simpler ways to achieve concurrency and remain highly performant, with no need for synchronization. Later on, we will leverage backpressure and other strategies to cope with rapidly-producing sources to prevent bottlenecks in your application. After covering custom operators, testing, and debugging, the book dives into hands-on examples using RxJava on Android as well as Kotlin.
Table of Contents (21 chapters)
Title Page
About the Author
About the Reviewers
Customer Feedback

Introducing RxJava concurrency

Concurrency in RxJava is simple to execute, but somewhat abstract to understand. By default, Observables execute work on the immediate thread, which is the thread that declared the Observer and subscribed it. In many of our earlier examples, this was the main thread that kicked off our main() method.

But as hinted in a few other examples, not all Observables will fire on the immediate thread. Remember those times we used Observable.interval(), as shown in the following code? Let's take a look:

import io.reactivex.Observable;
import java.util.concurrent.TimeUnit;

public class Launcher {

    public static void main(String[] args) {

        Observable.interval(1, TimeUnit.SECONDS)
                .map(i -> i + " Mississippi")

    public static void sleep(long millis) {
        try {
        } catch (InterruptedException e) {