Book Image

Functional Kotlin

Book Image

Functional Kotlin

Overview of this book

Functional programming makes your application faster, improves performance, and increases your productivity. Kotlin supports many of the popular and advanced functional features of functional languages. This book will cover the A-Z of functional programming in Kotlin. This book bridges the language gap for Kotlin developers by showing you how to create and consume functional constructs in Kotlin. We also bridge the domain gap by showing how functional constructs can be applied in business scenarios. We’ll take you through lambdas, pattern matching, immutability, and help you develop a deep understanding of the concepts and practices of functional programming. If you want learn to address problems using Recursion, Koltin has support for it as well. You’ll also learn how to use the funKtionale library to perform currying and lazy programming and more. Finally, you’ll learn functional design patterns and techniques that will make you a better programmer.By the end of the book, you will be more confident in your functional programming skills and will be able to apply them while programming in Kotlin.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Stream factory methods


The Streams API provides numerous ways to get a Stream instance. The following is the list of ways to create Streams that we are covering:

  • Stream Builder
  • Stream.empty()
  • Stream.of()
  • Stream.generate()
  • Stream.iterate()
  • Kotlin extension—asStream()

Among the preceding list, we've already seen how the Kotlin extension—asStream and the Stream.iterate function works (it'll work in the same way as the DoubleStream.iterate value, covered in the previous example). We will have a look at the rest.

Stream Builder

The Stream Builder interface makes it really easy to create an instance of Stream with ease. Have a look at the following example:

  fun main(args: Array<String>) { 
      val stream = Stream.builder<String>() 
              .add("Item 1") 
              .add("Item 2") 
              .add("Item 3") 
              .add("Item 4") 
              .add("Item 5") 
              .add("Item 6") 
              .add("Item 7") 
              .add("Item 8") 
              .add(...