Book Image

Learn Kotlin Programming - Second Edition

By : Stephen Samuel, Stefan Bocutiu
Book Image

Learn Kotlin Programming - Second Edition

By: Stephen Samuel, Stefan Bocutiu

Overview of this book

Kotlin is a general-purpose programming language used for developing cross-platform applications. Complete with a comprehensive introduction and projects covering the full set of Kotlin programming features, this book will take you through the fundamentals of Kotlin and get you up to speed in no time. Learn Kotlin Programming covers the installation, tools, and how to write basic programs in Kotlin. You'll learn how to implement object-oriented programming in Kotlin and easily reuse your program or parts of it. The book explains DSL construction, serialization, null safety aspects, and type parameterization to help you build robust apps. You'll learn how to destructure expressions and write your own. You'll then get to grips with building scalable apps by exploring advanced topics such as testing, concurrency, microservices, coroutines, and Kotlin DSL builders. Furthermore, you'll be introduced to the kotlinx.serialization framework, which is used to persist objects in JSON, Protobuf, and other formats. By the end of this book, you'll be well versed with all the new features in Kotlin and will be able to build robust applications skillfully.
Table of Contents (21 chapters)
Free Chapter
1
Section 1: Fundamental Concepts in Kotlin
5
Section 2: Practical Concepts in Kotlin
15
Section 3: Advanced Concepts in Kotlin

Rules

When annotating your data classes or classes with Serializable, you need to pay attention to what is possible and what is not possible. All the val and var class constructors are supported. However, a class constructor cannot have parameters. For example, the following code will yield a compilation error, since the b parameter is present:

@Serializable
class Data(val a: Int, b: Int)

Serializing classes handle the visibility of the properties regardless of the level (private, protected, and so on). In the next code snippet, the b property has been set as private:

@Serializable
class Data(val a: Int) {
private val b: String = "42"
}

There’s a catch when using serialization with property initializers and setters. Consider an adapted version of the previous Data class:

@Serializable
data class Data(val a: String) {
val b: String = compute()

private fun compute...