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


Parallelization, also called parallelism or parallel computing, is a broad term that can be used for any concurrent activity (including what we covered). But for the purposes of RxJava, let's define it as processing multiple emissions at a time for a given Observable. If we have 1000 emissions to process in a given Observable chain, we might be able to get work done faster if we process eight emissions at a time instead of one. If you recall, the Observable contract dictates that emissions must be pushed serially down an Observable chain and never race each other due to concurrency. As a matter of fact, pushing eight emissions down an Observable chain at a time would be downright catastrophic and wreak havoc. 

This seems to put us at odds with what we want to accomplish, but thankfully, RxJava gives you enough operators and tools to be clever. While you cannot push items concurrently on the same Observable, you are allowed to have multiple Observables running at once, each...