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

Getting started with Ktor

You're probably tired of creating to-do or shopping lists.

So, instead, in this chapter, the microservice will be for a cat shelter. The microservice should be able to do the following:

  • Supply an endpoint we can ping to check whether the service is up and running
  • List the cats currently in the shelter
  • Provide us with a means to add new cats

The framework we'll be using for our microservice in this chapter is called Ktor. It's a concurrent framework that's developed and maintained by the creators of the Kotlin programming language.

Let's start by creating a new Kotlin Gradle project:

  1. From your IntelliJ IDEA, select File | New | Project and choose Kotlin from New Project and Gradle Kotlin as your Build System.
  2. Give your project a descriptive name – CatsHostel, in my case – and choose Project JDK (in this case, we are using JDK 15):

    Figure 10.1 – Selecting the Project JDK type...