Book Image

Hands-On Design Patterns with Kotlin

By : Alexey Soshin
Book Image

Hands-On Design Patterns with Kotlin

By: Alexey Soshin

Overview of this book

Design patterns enable you as a developer to speed up the development process by providing you with proven development paradigms. Reusing design patterns helps prevent complex issues that can cause major problems, improves your code base, promotes code reuse, and makes an architecture more robust. The mission of this book is to ease the adoption of design patterns in Kotlin and provide good practices for programmers. The book begins by showing you the practical aspects of smarter coding in Kotlin, explaining the basic Kotlin syntax and the impact of design patterns. From there, the book provides an in-depth explanation of the classical design patterns of creational, structural, and behavioral families, before heading into functional programming. It then takes you through reactive and concurrent patterns, teaching you about using streams, threads, and coroutines to write better code along the way By the end of the book, you will be able to efficiently address common problems faced while developing applications and be comfortable working on scalable and maintainable projects of any size.
Table of Contents (13 chapters)

Constants

Since everything in Java is an object (unless you're a primitive type), we're used to putting all the constants inside our objects as static members.

And since Kotlin has companion objects, we usually try putting them there:

class MyClass {
companion object {
val MY_CONST = "My Const"
}
}

This will work, but you should remember that companion object is an object, after all.

So, this will be translated to the following code, more or less:

public final class Spock {
@NotNull
private static final String MY_CONST = "My Const";
public static final Spock.Companion Companion = new Spock.Companion(...);

public static final class Companion {
@NotNull
public final String getMY_CONST() {
return MyClass.MY_CONST;
}

private Companion() {
}
}
}

And the call to our constant looks like this:

String var1...