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

Flyweight

Flyweight is an object without any state. The name comes from it being very light. If you've been reading either one of the two previous chapters, you might already be thinking of a type of object that should be very light: a data class. But a data class is all about state.

So, is the data class related to the Flyweight design pattern at all?

To understand this design pattern better, we need to jump back in time some twenty years. Back in 1994, when the original Design Patterns book was published, your regular PC had 4 MB of RAM. During this period, one of the main goals of any process was to save that precious RAM, as you could fit only so much into it.

Nowadays, some cellphones have 8 GB of RAM. Bear that in mind when we discuss what the Flyweight design pattern is all about in this section.

Having said that, let's see how we can use our resources more efficiently, as this is always important!

Being conservative

Imagine we're building a...