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

Windowing


The window() operators are almost identical to buffer(), except that they buffer into other Observables rather than collections. This results in an Observable<Observable<T>> that emits Observables. Each Observable emission will cache emissions for each scope and then flush them once subscribed (much like the GroupedObservable from groupBy(), which we worked with in Chapter 4, Combining Observables). This allows emissions to be worked with immediately as they become available rather than waiting for each list or collection to be finalized and emitted. The window() operator is also convenient to work with if you want to use operators to transform each batch.

Just like buffer(), you can cut-off each batch using fixed sizing, a time interval, or a boundary from another Observable.

Fixed-size windowing

Let's modify our earlier example, where we buffered 50 integers into lists of size 8, but we will use window() to buffer them as Observables instead. We can reactively transform...