Book Image

Reactive Programming in Kotlin

By : Rivu Chakraborty
Book Image

Reactive Programming in Kotlin

By: Rivu Chakraborty

Overview of this book

In today's app-driven era, when programs are asynchronous, and responsiveness is so vital, reactive programming can help you write code that's more reliable, easier to scale, and better-performing. Reactive programming is revolutionary. With this practical book, Kotlin developers will first learn how to view problems in the reactive way, and then build programs that leverage the best features of this exciting new programming paradigm. You will begin with the general concepts of Reactive programming and then gradually move on to working with asynchronous data streams. You will dive into advanced techniques such as manipulating time in data-flow, customizing operators and provider and how to use the concurrency model to control asynchronicity of code and process event handlers effectively. You will then be introduced to functional reactive programming and will learn to apply FRP in practical use cases in Kotlin. This book will also take you one step forward by introducing you to Spring 5 and Spring Boot 2 using Kotlin. By the end of the book, you will be able to build real-world applications with reactive user interfaces as well as you'll learn to implement reactive programming paradigms in Android.
Table of Contents (20 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Dedication
Preface

Generating Flowable with backpressure at source


So far, we have learned to use standard libraries that handle backpressure at the downstream. However, is this optimal? Is it always desirable to cache and drop emissions whenever the downstream can't keep up? The answer to both questions is simply NO. Instead, the better policy would be to backpressure the source at the first place.

Flowable.generate() serves the exact same purpose. It's somewhat similar to Flowable.create(), but with a little difference. Let's take a look at an example, and then we will try to understand how it works and what are the differences between Flowable.create() and Flowable.generate().

Note

Note that use Flowable.fromIterable() as it respects backpressure. So, consider using Flowable.fromIterable() whenever you can convert your source to an Iterator. Use Flowable.generate() only where you need something more specific, as it is way more complex.

Consider the following code:

    fun main(args: Array<String>) { 
...