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Reactive Programming in Kotlin
Reactive Programming in Kotlin

Reactive Programming in Kotlin: Design and build non-blocking, asynchronous Kotlin applications with RXKotlin, Reactor-Kotlin, Android, and Spring

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Profile Icon Rivu Chakraborty
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$19.99 per month
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.3 (3 Ratings)
Paperback Dec 2017 322 pages 1st Edition
eBook
$27.98 $39.99
Paperback
$48.99
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Free Trial
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Arrow left icon
Profile Icon Rivu Chakraborty
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$19.99 per month
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.3 (3 Ratings)
Paperback Dec 2017 322 pages 1st Edition
eBook
$27.98 $39.99
Paperback
$48.99
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Free Trial
Renews at $19.99p/m
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Reactive Programming in Kotlin

Functional Programming with Kotlin and RxKotlin

Functional programming paradigms are slightly different than that of Object-oriented programming (OOP). It focuses on the use of declarative and expressive programs and immutable data rather than on statements. The definition of functional programming says functional programming is a programming system that relies on structuring the program as the evaluation of mathematical functions with immutable data, and it avoids state-change. It is a declarative programming paradigm that suggests use of small, reusable declarative functions.

We have seen the definition of functional programming; now, don't you want to delve into its definition and see what it exactly means? Do all languages support functional programming? If not, then which languages does and what about Kotlin? What exactly does reactive programming have to do with functional...

Introducing functional programming

So, functional programming wants you to distribute your programming logic into small pieces of reusable declarative small and pure functions. Distributing your logic into small pieces of code will make the code modular and non-complex, thus you will be able to refactor/change any module/part of the code at any given point without any effects to other modules.

Functional programming requires some interfaces and support from the language, thus we can't say any language is functional unless it gives some sort of support to implement functional programming. However, functional programming isn't something new; it is actually quite an old concept and has several languages supporting it. We call those languages functional programming languages, and the following is a list of some of the most popular functional programming languages:

  • Lisp
  • ...

Fundamentals of functional programming

Functional programming consists of few new concepts such as lambdas, pure functions, high-order functions, function types, and inline functions, which we will be learning. Quite interesting, isn't it?

Note that, although in many programmers word, pure functions and lambdas are the same, they are actually not. In the following part of this chapter, we will learn more about them.

Lambda expressions

Lambda or lambda expressions generally mean anonymous functions, that is, functions without names. You can also say a lambda expression is a function, but not every function is a lambda expression. Not every programming language provides support for lambda expressions, for instance, Java...

Applying functional programming to the ReactiveCalculator class

So, now, after trying to understand the ReactiveCalculator class from the previous chapter, we will try to optimize the code as well. Let's first take a look at the init block of the ReactiveCalculator class:

    init{ 
      nums = Pair(a,b) 
 
      subjectAdd.map({ it.first+it.second }).subscribe({println
("Add = $it")} )//1 subjectSub.map({ it.first-it.second }).subscribe({println
("Substract = $it")} ) subjectMult.map({ it.first*it.second }).subscribe
({println("Multiply = $it")} ) subjectDiv.map({ it.first/(it.second*1.0) }).subscribe
({println("Divide = $it")} ) subjectCalc.subscribe({ with(it) { calculateAddition() calculateSubstraction() calculateMultiplication() ...

Coroutines

Path breaking and, probably, the most exciting feature in Kotlin are coroutines. They are a new way to write asynchronous, non-blocking code somewhere like the threads, but way more simple, efficient, and lightweight. Coroutines were added in Kotlin 1.1 and are still experimental, so think before using it in production.

In the later chapters of this book, you'll learn about Schedulers in RxKotlin, which encapsulates the complexities of threading, but you can use it only in RxKotlin chain, while you can use coroutines anywhere and everywhere. That is indeed a path-breaking feature of Kotlin. They provide a great abstraction on threads, making context changes and concurrency easier.

Keep in mind that RxKotlin does not use coroutines yet; the reason is quite simple–both coroutines and Schedulers in RxKotlin share nearly the same internal architecture; while...

Functional programming – monads

Functional programming is incomplete without monads. If you are into functional programming, then you know it very well; otherwise, you are hearing it for the first time. So, what is a monad? Let's learn about it. The concept of monad is quite abstract; the definition says monad is a structure that creates a new type by encapsulating a value and adding some extra functionalities to it. So, let's start by using a monad; take a look at the following program:

    fun main(args: Array<String>) { 
      val maybeValue: Maybe<Int> = Maybe.just(14)//1 
      maybeValue.subscribeBy(//2 
        onComplete = {println("Completed Empty")}, 
        onError = {println("Error $it")}, 
        onSuccess = { println("Completed with value $it")} 
      ) 
      val maybeEmpty:Maybe<Int> = Maybe.empty...

Introducing functional programming


So, functional programming wants you to distribute your programming logic into small pieces of reusable declarative small and pure functions. Distributing your logic into small pieces of code will make the code modular and non-complex, thus you will be able to refactor/change any module/part of the code at any given point without any effects to other modules.

Functional programming requires some interfaces and support from the language, thus we can't say any language is functional unless it gives some sort of support to implement functional programming. However, functional programming isn't something new; it is actually quite an old concept and has several languages supporting it. We call those languages functional programming languages, and the following is a list of some of the most popular functional programming languages:

  • Lisp
  • Clojure
  • Wolfram
  • Erlang
  • OCaml
  • Haskell
  • Scala
  • F#

Lisp and Haskell are some of the oldest languages and are still used today in academia and...

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Key benefits

  • • Learn how to solve blocking user experience with Reactive Programming and get deep insights into RxKotlin
  • • Integrate Reactive Kotlin with Spring and build fantastic Android Apps with RxKotlin and RxAndroid
  • • Build reactive architectures that reduce complexity throughout the development process and make your apps(web and Android) scalable

Description

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.

Who is this book for?

This book is for Kotlin developers who would like to build fault-tolerant, scalable, and distributed systems. A basic knowledge of Kotlin is required, but no prior knowledge of reactive programming.

What you will learn

  • • Learn about reactive programming paradigms and how reactive programming can improve your existing projects
  • • Gain in-depth knowledge in RxKotlin 2.0 and the ReactiveX Framework
  • • Use RxKotlin with Android
  • • Create your own custom operators in RxKotlin
  • • Use Spring Framework 5.0 with Kotlin
  • • Use the reactor-kotlin extension
  • • Build Rest APIs with Spring, Hibernate, and RxKotlin
  • • Use testSubscriber to test RxKotlin applications
  • • Use backpressure management and Flowables

Product Details

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Publication date : Dec 05, 2017
Length: 322 pages
Edition : 1st
Language : English
ISBN-13 : 9781788473026
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Product Details

Publication date : Dec 05, 2017
Length: 322 pages
Edition : 1st
Language : English
ISBN-13 : 9781788473026
Vendor :
Google
Category :
Languages :
Concepts :
Tools :

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Table of Contents

12 Chapters
A Short Introduction to Reactive Programming Chevron down icon Chevron up icon
Functional Programming with Kotlin and RxKotlin Chevron down icon Chevron up icon
Observables, Observers, and Subjects Chevron down icon Chevron up icon
Introduction to Backpressure and Flowables Chevron down icon Chevron up icon
Asynchronous Data Operators and Transformations Chevron down icon Chevron up icon
More on Operators and Error Handling Chevron down icon Chevron up icon
Concurrency and Parallel Processing in RxKotlin with Schedulers Chevron down icon Chevron up icon
Testing RxKotlin Applications Chevron down icon Chevron up icon
Resource Management and Extending RxKotlin Chevron down icon Chevron up icon
Introduction to Web Programming with Spring for Kotlin Developers Chevron down icon Chevron up icon
REST APIs with Spring JPA and Hibernate Chevron down icon Chevron up icon
Reactive Kotlin and Android Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Half star icon Empty star icon Empty star icon 2.3
(3 Ratings)
5 star 33.3%
4 star 0%
3 star 0%
2 star 0%
1 star 66.7%
Amazon カスタマー Jun 04, 2019
Full star icon Full star icon Full star icon Full star icon Full star icon 5
The contents are substantial.
Amazon Verified review Amazon
Amazon Customer Jan 25, 2018
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
Poorly written and edited. Many errors in the text and examples. The examples are quite convoluted which obscures the point the author is trying to make.
Amazon Verified review Amazon
Arby Jan 17, 2021
Full star icon Empty star icon Empty star icon Empty star icon Empty star icon 1
poorly written. short on definitions and explanations. long convoluted examples. most of the time it isn't clear if his goal is to teach his audience or try to overwhelm and impress his audience.
Amazon Verified review Amazon
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