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

Sidekick channel

The Sidekick channel design pattern allows us to offload some work from our main worker to a back worker.

Up until now, we've only discussed the use of select as a receiver. But we can also use select to send items to another channel. Let's look at the following example.

First, we'll declare batman as an actor coroutine that processes 10 messages per second:

val batman = actor<String> {
    for (c in channel) {
        println("Batman is beating some sense into $c")
        delay(100)
    }
}

Next, we'll declare robin as another actor coroutine that is a bit slower and processes only four messages per second:

val robin = actor<String> {
    for (c in channel) {
        println("Robin is beating some sense into $c")
 ...