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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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

CPU speeds have increased significantly, making parallelization unnecessary.


The procedural programming paradigm has become more popular.




The object-oriented programming paradigm is exceptionally good at running parallel tasks.


CPU speeds cannot be increased as much as in the past, making parallelization necessary.

Why has functional programming gained significant momentum in the past 15 years?



Why has functional programming gained significant momentum in the past 15 years?

The object can change between input and output


The object cannot change between input and output


What does immutability mean in functional programming?


What does immutability mean in functional programming?

It will print "a", "b", and "c" in that order, then terminate.


It will print "a", "b", and "c" in that order, then throw a `ConcurrentModificationException`.



It will print "c", "b", and "a" in that order, then terminate.


It will print "c", "b", and "a" in that order, then throw a `ConcurrentModificationException`.


What will happen when you run the following code?
```
fun <T> printAndClear(list: MutableList<T>) {
 for (e in list) {
 println(e)
 list.remove(e)
 }
}
printAndClear(mutableListOf("a", "b", "c"))
```

What will happen when you run the following code?
<pre><code>fun &lt;T&gt; printAndClear(list: MutableList&lt;T&gt;) {
 for (e in list) {
 println(e)
 list.remove(e)
 }
}
printAndClear(mutableListOf(&quot;a&quot;, &quot;b&quot;, &quot;c&quot;))
</code></pre>

Which of the following is a higher-order function in the Kotlin standard library?


Which of the following is a higher-order function in the Kotlin standard library?

What is the syntax for declaring an anonymous function in Kotlin?


What is the syntax for declaring an anonymous function in Kotlin?

A way to refer to the implicit parameter in a lambda.


A keyword that is used to declare variables.

What is the <code>it</code> notation in Kotlin?

What is the return type of the higher-order function in the following code?
```
fun counter(): () -> Int {
    var i = 0
    return { i++ }
}
```


What is the return type of the higher-order function in the following code?
<pre><code>fun counter(): () -&gt; Int {
 var i = 0
 return { i++ }
}
</code></pre>

The property of pure functions that their invocation could be replaced by their result if we knew it ahead of time.


The property of impure functions that they are hard to test and reason about.


The property of closures that they have access to the local variables of the function that wraps them.


The property of immutable values that they cannot be changed once they are created.


What is referential transparency?

What is the real-world scenario where currying can be used?


What is the real-world scenario where currying can be used?

```
fun log(level: LogLevel, message: String) = println("$level: $message")
```


```
fun sum(numbers: Set<Int>): Double { 
 return numbers.sumBy { it } }
````

```
fun createLogger(level: LogLevel): (String) -> Unit { return { message: String -> log(level, message) } }
```


Which of the following is a pure function?


Which of the following is a pure function?

An optimization that improves the performance of recursive functions.


An optimization that avoids stack overflow errors in recursive functions with only one recursive call.


An optimization that allows for multiple recursive calls in a function.


An optimization that eliminates the need for recursive functions.


What is tail recursion optimization?

No, it only works for functions with a single recursive call.


It depends on the programming language used.


It depends on the complexity of the function.

Can tail recursion optimization be applied to functions with multiple recursive calls?


Can tail recursion optimization be applied to functions with multiple recursive calls?

Practice your learning outcomes and test your understanding of the material presented in this chapter by taking this quiz.


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

Quiz on Functional Programming in Kotlin