Book Image

Learning RxJava

By : Nield
Book Image

Learning RxJava

By: 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 (14 chapters)

Ambiguous

After covering merging and concatenation, let's get an easy combine operation out of the way. The Observable.amb() factory (amb stands for ambiguous) will accept an Iterable<Observable<T>> and emit the emissions of the first Observable that emits, while the others are disposed of. The first Observable with an emission is the one whose emissions go through. This is helpful when you have multiple sources for the same data or events and you want the fastest one to win.

Here, we have two interval sources and we combine them with the Observable.amb() factory. If one emits every second while the other every 300 milliseconds, the latter is going to win because it will emit first:

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

public class Launcher {
public static void main(String[] args) {

//emit...