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

Summary

This chapter was dedicated to practicing functional programming with reactive principles and learning the building blocks of functional programming in Kotlin. We also learned about the main benefits of reactive systems. For example, such systems should be responsive, resilient, elastic, and driven by messaging.

Now, you should know how to transform your data, filter your collections, and find elements within the collection that meet your criteria.

You should also better understand the difference between cold and hot streams. A cold stream, such as a flow, starts working only when someone subscribes to it. A new subscriber will usually receive all of the events. On the other hand, a hot stream, such as a channel, continuously emits events, even if nobody is listening to them. A new subscriber will receive only the events that were sent after the subscription was made.

We also discussed the concept of backpressure, which can be implemented in a flow. For example, if...