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
Credits
About the Author
Acknowledgements
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Automatic connection


There are definitely times you will want to manually call connect() on ConnectableObservable to precisely control when the emissions start firing. There are convenient operators that automatically call connect() for you, but with this convenience, it is important to have awareness of their subscribe timing behaviors. Allowing an Observable to dynamically connect can backfire if you are not careful, as emissions can be missed by Observers.

autoConnect()

The autoConnect() operator on ConnectableObservable can be quite handy. For a given ConnectableObservable<T>, calling autoConnect() will return an Observable<T> that will automatically call connect() after a specified number of Observers are subscribed. Since our previous example had two Observers, we can streamline it by calling autoConnect(2) immediately after publish():

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

public class Launcher {
    public static void main(String...