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)

Reified

Since the inline function is copied, we can get rid of one of the major JVM limitationstype erasure. After all, inside the function, we know exactly what type we're getting.

Let's look at the following example. You would like to create a generic function, which will receive a number but will print it only if it's of the same type as the function.

You can try writing something like this:

fun <T> printIfSameType(a: Number) {
if (a is T) { // <== Error
println(a)
}
}

But this code won't compile with an error as follows:

Cannot check for instance of erased type: T

What we usually do in Java, in this case, is pass the class as an argument:

fun <T: Number> printIfSameType(clazz: KClass<T>, a: Number) {
if (clazz.isInstance(a) ) {
println(a)
}
}

We can check this code by running the following two lines...