Book Image

Kotlin Design Patterns and Best Practices - Second Edition

By : Alexey Soshin
Book Image

Kotlin Design Patterns and Best Practices - Second Edition

By: Alexey Soshin

Overview of this book

This book shows you how easy it can be to implement traditional design patterns in the modern multi-paradigm Kotlin programming language, and takes you through the new patterns and paradigms that have emerged. This second edition is updated to cover the changes introduced from Kotlin 1.2 up to 1.5 and focuses more on the idiomatic usage of coroutines, which have become a stable language feature. You'll begin by learning about the practical aspects of smarter coding in Kotlin, as well as understanding basic Kotlin syntax and the impact of design patterns on your code. The book also provides an in-depth explanation of the classical design patterns, such as Creational, Structural, and Behavioral families, before moving on to functional programming. You'll go through reactive and concurrent patterns, and finally, get to grips with coroutines and structured concurrency to write performant, extensible, and maintainable code. By the end of this Kotlin book, you'll have explored the latest trends in architecture and design patterns for microservices. You’ll also understand the tradeoffs when choosing between different architectures and make informed decisions.
Table of Contents (17 chapters)
1
Section 1: Classical Patterns
6
Section 2: Reactive and Concurrent Patterns
11
Section 3: Practical Application of Design Patterns

Mediator

The development team of our game has some real problems – and they're not related to code directly. As you may recall, our little indie company consists of only me, a canary named Michael that acts as a product manager, and two cat designers that sleep most of the day but produce some decent mockups from time to time. We have no Quality Assurance (QA) whatsoever. Maybe that's one of the reasons our game keeps crashing all the time.

Recently Michael has introduced me to a parrot named Kenny, who happens to be QA:

interface QA { 
    fun doesMyCodeWork(): Boolean 
} 
 
interface Parrot { 
    fun isEating(): Boolean 
    fun isSleeping(): Boolean 
} 
 
object Kenny : QA, Parrot { 
    // Implements interface methods based on parrot     // schedule 
}

Kenny is a simple object that implements two interfaces: QA, to do QA work, and Parrot, because it&apos...