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.

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Kotlin

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Kotlin_SPA

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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

## Adding a basic endpoint
Notice that no matter which URL we specify, we always get the same result. Of course, that's not what we want to achieve. Let's start by adding the most basic endpoint, which will only tell us that the service is up and running.

For that, we'll use `Router` in our `App.kt` file:
```
val vertx = Vertx.vertx()
val router = Router.router(vertx)
...
```
Using `Router` lets us specify handlers for different HTTP methods and URLs.
Now, let's add a `/status` endpoint in our `App.kt` file that will return an HTTP status code of `200` and a message stating `OK` to our user:

```kotlin
router.get("/status").handler { ctx ->
    ctx.response()
    .setStatusCode(200)
    .end("OK")
}
vertx.createHttpServer()
    .requestHandler(router)
    .listen(8081)
```
Now, instead of specifying the request handler as a block, we will pass this function to our `router` object. This makes our code easier to manage.
## Returning JSON instead of text
We learned how to return a flat text response in the very first example. So, now, let's return JSON instead. Most real-life applications use JSON for communication. Let's replace the body of our status handler with the following code:

```kotlin
val json = json {
    obj(
       "status" to "OK"
    )
}
ctx.response()
   .setStatusCode(200)
   .end(json.toString())
```
Here, we are using a DSL to create a JSON object.




Learn how to handle the routing requests in a Vert.x application.

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

Routing in Vert.x

Adding a basic endpoint