Example Kotlin

example.kt

import java.math.BigDecimal
import java.time.YearMonth

enum class VehicleType {
    SUV, Sedan
}

interface CarModel {
    val vehicleType: VehicleType
}

interface Electric {
    fun getNumOfMotors(): Int
    fun getBattery(): BatteryInfo
}

enum class BatterType {
    LiFeP, NiMnCo, Sodium
}

enum class Unit {
    Watt, Ampere, Volt, Second, KiloWattHour
}

sealed interface UnitAmount {
    val amount: BigDecimal
    val unit: Unit
}

data class Energy(override val amount: BigDecimal) : UnitAmount {
    override val unit: Unit get() = Unit.KiloWattHour
}

data class Voltage(override val amount: BigDecimal) : UnitAmount {
    override val unit: Unit get() = Unit.Volt
}

infix fun BatterType.`🔋`(energy: Energy) = BatteryInfo(this, energy)

fun Number.kWh(): Energy = Energy(BigDecimal.valueOf(this.toDouble()))

data class BatteryInfo(val type: BatterType, val energy: Energy)

data class Vehicle(val model: CarModel, val yearMonth: YearMonth)

enum class TeslaTrim {
    RearWheelDrive, LongRange, Performance
}

fun TeslaTrim.getNumOfMotors(): Int = when (this) {
    TeslaTrim.RearWheelDrive -> 1
    TeslaTrim.LongRange, TeslaTrim.Performance -> 2
}

sealed class TeslaModel(override val vehicleType: VehicleType) : CarModel, Electric

data class Model3(val trim: TeslaTrim) : TeslaModel(VehicleType.Sedan) {
    override fun getNumOfMotors(): Int = trim.getNumOfMotors()

    override fun getBattery() = when (trim) {
        TeslaTrim.RearWheelDrive -> BatterType.LiFeP `🔋` 60.kWh()
        TeslaTrim.LongRange, TeslaTrim.Performance -> BatterType.NiMnCo `🔋` 82.kWh()
    }
}

data class ModelY(val trim: TeslaTrim) : TeslaModel(VehicleType.SUV) {
    override fun getNumOfMotors(): Int = trim.getNumOfMotors()

    override fun getBattery() = when (trim) {
        TeslaTrim.RearWheelDrive -> BatterType.LiFeP `🔋` 60.kWh()
        TeslaTrim.LongRange, TeslaTrim.Performance -> BatterType.NiMnCo `🔋` 82.kWh()
    }
}

data class ModelS(val isPlaid: Boolean) : TeslaModel(VehicleType.Sedan) {
    override fun getNumOfMotors(): Int = if (isPlaid) 3 else 2
    override fun getBattery() = BatterType.NiMnCo `🔋` 100.kWh()
}

data class ModelX(val isPlaid: Boolean) : TeslaModel(VehicleType.SUV) {
    override fun getNumOfMotors(): Int = if (isPlaid) 3 else 2
    override fun getBattery() = BatterType.NiMnCo `🔋` 100.kWh()
}


val Vehicle.numOfCabins: Int
    get() = when (model.vehicleType) {
        VehicleType.SUV -> 2
        VehicleType.Sedan -> 3
    }

val modelY = ModelY(TeslaTrim.Performance)

val myCar = Vehicle(
    model = modelY, yearMonth = YearMonth.of(2021, 3)
)

myCar.numOfCabins
modelY.getNumOfMotors()

// dsl builder example

sealed interface Parts

data class Wheel(val size: Int) : Parts

class Window : Parts

sealed class BillOfMaterials : Parts {

    val parts: MutableList<Parts> = mutableListOf()


    fun bodyInWhite(builder: BodyInWhite.() -> kotlin.Unit) {

    }

    fun underBody(builder: UnderBody.() -> kotlin.Unit) {

    }
}

class Car : BillOfMaterials()

class BodyInWhite : BillOfMaterials() {
    fun window(number: Int) {
        (0 until number).forEach {
            parts.add(Window())
        }
    }
}

class UnderBody : BillOfMaterials() {
    fun wheels(number: Int, sizeBuilder: () -> Int) {
        (0 until number).forEach {
            parts.add(Wheel(sizeBuilder()))
        }
    }
}

fun carBom(bomBuilder: BillOfMaterials.() -> kotlin.Unit): BillOfMaterials {
    val bom = Car()
    bomBuilder(bom)
    return bom
}

val carBom = carBom {
    bodyInWhite {
        window(6)
    }

    underBody {
        wheels(4) {
            19
        }
    }
}

class MyResource: AutoCloseable {
    override fun close() {
        TODO("Not yet implemented")
    }

}

MyResource().use { 
    
}

val value = mutableListOf<Int>().apply {
    add(1)
    add(2)
    add(3)
    removeAt(2)
}

carBom