Design Patterns in Kotlin

The book "Design Patterns in Kotlin" is a comprehensive guide to applying classic design patterns (GoF) in the modern programming language Kotlin. The author, Alexey Smirnov, an experienced Kotlin developer and architect, shares practical knowledge that will help you write clean, maintainable, and scalable code.

What is this book about?

The book covers all 23 design patterns described in the famous "Gang of Four" book, but adapted to the features of Kotlin:

• Creational patterns (Singleton, Factory Method, Abstract Factory, Builder, Prototype) — how to create objects flexibly and efficiently.
• Structural patterns (Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy) — how to build complex class and object structures.
• Behavioral patterns (Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor) — how to organize interaction between objects.

Each pattern is examined according to a unified scheme: problem, solution, structure with a UML diagram, implementation example in Kotlin, as well as application tips and alternatives.

Who is this book for?

• Developers already familiar with the basics of Kotlin who want to deepen their knowledge of software architecture.
• Programmers transitioning from Java to Kotlin — the book will show how to use Kotlin idioms (extension functions, data class, object, sealed class) to simplify patterns.
• Technical leaders and architects striving to create flexible and easily maintainable systems.

What will you learn?

• How to correctly select and apply patterns in real projects.
• How Kotlin simplifies the implementation of classic patterns (e.g., Singleton via object, Builder via named arguments and default values).
• How to combine patterns to solve complex architectural problems.
• How to avoid common mistakes and anti-patterns.
• How to test code built using patterns.

The book contains over 100 code examples, ready to use in your projects. All examples are accompanied by explanations and UML diagrams for clarity. This is not dry theory, but a practical guide that you will constantly re-read and use as a reference.

"Design Patterns in Kotlin" will become your go-to book if you strive to write professional code that is easy to extend and maintain.