Advanced Kotlin (DataClass, Delegation, InlineClass, InnerClass, Object, SealedClass, TypeAlias)

DataClass.kt

fun main(args: Array<String>) {
    val reza = Student("reza", 22)
    val ghasem = Student("ghasem", 22)

    println(ghasem.hashCode())
}

/*class Student(val name: String, private val age: Int) {

    fun printPlan() = "Plan"

    override fun toString(): String {
        return "(name=$name, age=$age)"
    }

    override fun hashCode(): Int {
        return toString().hashCode()
    }

    override fun equals(other: Any?): Boolean {
        return this.age == (other as Student).age
    }
}*/

data class Student(val name: String = "", var age: Int = 0) {
    fun foo() = ""
}

Delegation.kt

interface CoffeeMachine {
    fun makeSmallCoffee()
    fun makeLargeCoffee()
}

class NormalCoffeeMachine : CoffeeMachine {
    override fun makeSmallCoffee() = println("Normal: Making small coffee")

    override fun makeLargeCoffee() = println("Normal: Making large coffee")
}

//Decorator:
class EnhancedCoffeeMachine(val coffeeMachine: CoffeeMachine) : CoffeeMachine by coffeeMachine {

    // overriding behaviour
    override fun makeLargeCoffee() {
        println("Enhanced: Making large coffee")
        coffeeMachine.makeLargeCoffee()
    }

    // extended behaviour
    fun makeCoffeeWithMilk() {
        println("Enhanced: Making coffee with milk")
        coffeeMachine.makeSmallCoffee()
        println("Enhanced: Adding milk")
    }
}

fun main() {
    val normalCoffeeMachine = NormalCoffeeMachine()
    normalCoffeeMachine.makeSmallCoffee()
    normalCoffeeMachine.makeLargeCoffee()

    val enhancedCoffeeMachine = EnhancedCoffeeMachine(normalCoffeeMachine)
    enhancedCoffeeMachine.makeSmallCoffee()
    enhancedCoffeeMachine.makeLargeCoffee()
    enhancedCoffeeMachine.makeCoffeeWithMilk()
}

InlineClass.kt

import kotlin.time.Duration
import kotlin.time.ExperimentalTime

interface Validation {
    fun isValid(): Boolean
}

@JvmInline
value class Email(val value: String) : Validation {
    override fun isValid(): Boolean = value.matches(Regex("""^[a-zA-Z0-9_!#$%&’*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+$"""))
}

@JvmInline
value class Phone(val value: String) : Validation {
    override fun isValid() = value.matches(Regex("""09\d{9}|\+989\d{9}"""))
}

@OptIn(ExperimentalTime::class)
fun main() {
    val email = Email("ghasem79.dev@gmail.com")
    println("${email.value} ${email.isValid()}")

    val phone = Phone("09150000000")
    println("${phone.value} ${phone.isValid()}")

    delayTime(Duration.hours(2.5))
}

@OptIn(ExperimentalTime::class)
fun delayTime(value: Duration) {
    println(value.inWholeMinutes)
}

InnerClass.kt

class Shape {
    private val color = "red"

    inner class Circle {
        fun foo() = println("Circle: $color")
    }

    class Rectangle {
        fun foo() = println("Rectangle")
    }
}

fun main() {
    Shape().Circle().foo()
    Shape.Rectangle().foo()
}

Object.kt

object Database {
    private val list = mutableListOf<String>()

    init {
        println("init")
    }

    fun save(value: String) {
        list.add(value)
    }

    fun sout() {
        list.forEach(::println)
    }
}

fun main() {
    Database.save("ali")
    Database.save("javad")
    Database.save("jakode")

    Database.sout()
}

SealedClass.kt

enum class State(val value: Int) {
    Open(0), Closed(1)
}

data class Door(var state: State = State.Closed)

sealed interface Result<T>
object Loading : Result<Nothing>
data class Success<T>(val value: T) : Result<T>
data class Error(val exception: Exception) : Result<Nothing>

fun main() {
    val door = Door()
    println(door.state.value)
    val result: Result<Nothing> = Loading

    when (result) {
        is Loading -> {
            println("loading")
        }
        is Success -> {
            println("Success : ${result.value}")
        }
        is Error -> {
            println("Error : ${result.exception.message}")
        }
    }
}

TypeAlias.kt

typealias Location = Pair<Double, Double>

fun main() {
    val location = Location(12.256, 13.265)
    println(location)
}