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

Collection operators


Collection operators will accumulate all emissions into a collection such as a list or map and then emit that entire collection as a single emission. Collection operators are another form of reducing operators since they consolidate emissions into a single one. We will cover them separately since they are a significant category on their own, though.

Note

Note that you should avoid reducing emissions into collections for the sake of it. It can undermine the benefits of reactive programming where items are processed in a beginning-to-end, one-at-a-time sequence. You only want to consolidate emissions into collections when you are logically grouping them in some way.

 

toList()

A common collection operator is toList(). For a given Observable<T>, it will collect incoming emissions into a List<T> and then push that entire List<T> as a single emission (through Single<List<T>>). In the following code snippet, we collect string emissions into a List...