Gain insights into Kotlin language essentials and delve into design patterns and best practices. Discover functional programming techniques to enhance code reuse, robustness, and build reliable, scalable projects.

Packt MBE - Kotlin Design Patterns and Best Practices.png

Kotlin_optimized.tar.gz

Kotlin

Kotlin_Co

Kotlin_SPA

Cats_Hostel

Cats_Shelter(1..5)

Cats_Shelter(6-7-8)

Design patterns enable developers to speed up the development process by providing proven development paradigms. Reusing design patterns helps prevent complex issues that can cause major problems. Moreover, it improves your codebase, promotes code reuse, and makes an architecture more robust.

In this course, you will start with a gentle introduction of the Kotlin language. You will explore design patterns that are part of the best practices that help developers use Kotlin efficiently. Design patterns appeared in the era of object-oriented languages such as C++ and Java. You will learn the language features that Kotlin provides, which allow developers to program in a functional style and implement the design patterns.

After taking this course, you’ll be able to take your knowledge of Kotlin, design patterns, and associated best practices to the software industry and apply it to build reliable, scalable, and maintainable projects.

Kotlin Design Patterns and Best Practices

The framework we'll be using for our microservice in this chapter is called **Ktor**. It's a concurrent framework that's developed and maintained by the creators of the Kotlin programming language.

For a Kotlin Gradle project, we have some requirements. 

### Technical requirements

* JDK 11 or later
* IntelliJ IDEA
* Gradle 6.8 or later
* PostgreSQL 14 or later

> **Note**: We do not need the IDE for the course, as a code development environment is provided here.
 
You’re probably tired of creating to-do or shopping lists.

So, instead, in this chapter, the microservice will be for a `cat shelter`. The microservice should be able to do the following:
* Supply an endpoint we can ping to check whether the service is up and running
* List the cats currently in the shelter
* Provide us with a means to add new cats.



To start, to create a new Kotlin Gradle project, we follow these steps:

1. We'll open the terminal and create a new project by typing `gradle init`.
2. Then we'll select "application" as the project type, "Kotlin" as the implementation language, "no" for split functionality for subprojects, and "Kotlin" the as build script DSL.
3. We'll name our project a descriptive name---like CatsHostel---and use the same for the root project name and press enter.

>**Note**: These steps have already been done, and the project is available in the workspace below.



Learn how to build a Ktor application in Kotlin and execute a "Hello World" program.

Getting Started with Kotlin

Working with Creational Patterns

Understanding Structural Patterns

Getting Familiar with Behavioral Patterns

Introducing Functional Programming

Threads and Coroutines

Controlling the Data Flow

Designing for Concurrency

Idioms and Anti-Patterns

Concurrent Microservices with Ktor

Reactive Microservices with Vert.x

Conclusion

Getting Started and Adding the Dependencies

Technical requirements