Book Image

Learn Kotlin Programming - Second Edition

By : Stephen Samuel, Stefan Bocutiu
Book Image

Learn Kotlin Programming - Second Edition

By: Stephen Samuel, Stefan Bocutiu

Overview of this book

Kotlin is a general-purpose programming language used for developing cross-platform applications. Complete with a comprehensive introduction and projects covering the full set of Kotlin programming features, this book will take you through the fundamentals of Kotlin and get you up to speed in no time. Learn Kotlin Programming covers the installation, tools, and how to write basic programs in Kotlin. You'll learn how to implement object-oriented programming in Kotlin and easily reuse your program or parts of it. The book explains DSL construction, serialization, null safety aspects, and type parameterization to help you build robust apps. You'll learn how to destructure expressions and write your own. You'll then get to grips with building scalable apps by exploring advanced topics such as testing, concurrency, microservices, coroutines, and Kotlin DSL builders. Furthermore, you'll be introduced to the kotlinx.serialization framework, which is used to persist objects in JSON, Protobuf, and other formats. By the end of this book, you'll be well versed with all the new features in Kotlin and will be able to build robust applications skillfully.
Table of Contents (21 chapters)
Free Chapter
1
Section 1: Fundamental Concepts in Kotlin
5
Section 2: Practical Concepts in Kotlin
15
Section 3: Advanced Concepts in Kotlin

Coroutine dispatchers

When launching a coroutine, you may wish to control which thread or thread pool the coroutine actually executes on. A coroutine dispatcher allows you to do this. When a coroutine begins execution, or is resumed after suspension, the dispatcher is used to select a thread for that execution.

The thread selected at the start of a coroutine need not be the same thread selected after resumption. For example, a thread pool may be used and any of the available threads could be selected after a function resumes.

The coroutine library ships with several built in dispatchers. These are as follows:

  • Dispatchers.Default: This uses a shared thread pool, generally set to the number of cores in the CPU (although the minimum is two). This kind of dispatcher is recommended for CPU bound tasks.
  • Dispatchers.IO: This uses a shared thread pool that will grow as required, depending...