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

Proxy

Much like the Decorator design pattern, the Proxy design pattern extends an object's functionality. However, unlike a decorator, which always does what it's told, having a proxy may mean that when asked to do something, the object does something totally different.

When we discussed Creational Patterns in Chapter 2, Working with Creational Patterns, we already touched on the idea of expensive objects. For example, an object that accesses network resources or takes a lot of time to create.

We at the Funny Cat App provide our users with funny cat images on a daily basis. On our homepage and mobile application, each user sees a lot of pictures of funny cats. When they click or touch any of those images, it expands to its full-screen glory.

Fetching cat images over the network is very expensive, and it consumes a lot of memory, especially if those are images of cats that tend to indulge in a second dessert after dinner. What we want to do is fetch the full-sized...