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

Reactive principles

We'll start this chapter with a brief detour into Reactive programming, as it forms the foundation of the data streaming concept.

Reactive programming is a paradigm based on functional programming in which we model our logic as a set of operations in a data stream. The fundamental concepts of reactive programming are summarized nicely in The Reactive Manifesto (https://www.reactivemanifesto.org).

According to this manifesto, reactive programs should be all of the following:

  • Responsive
  • Resilient
  • Elastic
  • Message-driven

To understand these four principles, we'll use an example.

Let's imagine you are calling your Internet Service Provider, since your internet is slow, for example. Do you have this picture in your mind? Let's start then.

Responsive principle

How much time are you willing to spend waiting on the line? That depends on the urgency of the situation and how much time you have. If you're in...