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val userId: Long = 12
val deviceUuid: Long = 1234
val carSerialId: Long = 12345
def getHashCode(
userId: Long,
deviceUuid: Long,
carSerialId: Long
): String = {
val userIdPlus: Long = userId + 1
val deviceUuidPlus: Long = deviceUuid + 2
val carSerialIdPlus: Long = carSerialId + 3
s"$userIdPlus-$deviceUuidPlus-$carSerialIdPlus"
}
getHashCode(userId, deviceUuid, carSerialId) // Right Answer = res0: String = 13-1236-12348
getHashCode(deviceUuid, userId, carSerialId) // Wrong Answer = res1: String = 1235-14-12348
// Lets do it by case class
case class UserIdCaseClass(userId: Long)
case class DeviceUuidCaseClass(deviceUuid: Long)
case class CarSerialIdCaseClass(carSerialId: Long)
def getHashCodeCaseClass(
userIdCaseClass: UserIdCaseClass,
deviceUuidCaseClass: DeviceUuidCaseClass,
carSerialIdCaseClass: CarSerialIdCaseClass
): String = {
val userIdPlus: Long = userIdCaseClass.userId + 1
val deviceUuidPlus: Long = deviceUuidCaseClass.deviceUuid + 2
val carSerialIdPlus: Long = carSerialIdCaseClass.carSerialId + 3
s"$userIdPlus-$deviceUuidPlus-$carSerialIdPlus"
}
getHashCodeCaseClass(UserIdCaseClass(userId), DeviceUuidCaseClass(deviceUuid), CarSerialIdCaseClass(carSerialId)) // Right Answer = res2: String = 13-1236-12348
//getHashCodeCaseClass(DeviceUuidCaseClass(deviceUuid), UserIdCaseClass(userId), CarSerialIdCaseClass(carSerialId)) // Not Even Compiled!
import shapeless.tag
import shapeless.tag.@@
trait UserIdTag
trait DeviceUuidTag
trait CarSerialIdTag
type UserId = Long @@ UserIdTag
type DeviceUuid = Long @@ DeviceUuidTag
type CarSerialId = Long @@ CarSerialIdTag
def getHashCodeTagged(
userId: UserId,
deviceUuid: DeviceUuid,
carSerialId: CarSerialId
): String = {
val userIdPlus: Long = userId + 1
val deviceUuidPlus: Long = deviceUuid + 2
val carSerialIdPlus: Long = carSerialId + 3
s"$userIdPlus-$deviceUuidPlus-$carSerialIdPlus"
}
val taggedUserId: UserId = tag[UserIdTag][Long](userId)
val taggedDeviceUuid: DeviceUuid = tag[DeviceUuidTag][Long](deviceUuid)
val taggedCarSerialId: CarSerialId = tag[CarSerialIdTag][Long](carSerialId)
getHashCodeTagged(taggedUserId, taggedDeviceUuid, taggedCarSerialId) // Right Answer = res2: String = 13-1236-12348
//getHashCodeTagged(taggedDeviceUuid, taggedCarSerialId, taggedUserId) // Not Even Compiled
// Can't Override
def getId(userId: UserId): Long = userId + 1
//def getId(deviceUuid: DeviceUuid): Long = deviceUuid + 2 // Not Compiled because tagged type erased after compile
//def getId(carSerialId: CarSerialId): Long = carSerialId + 3 // Not Compiled because tagged type erased after compile
// Let's do by either
def getUserIdOrDeviceIdOrCarSerialId(
id: Either[UserId, Either[DeviceUuid, CarSerialId]]
): Long = id match {
case Left(userId) => userId + 1
case Right(Left(deviceUuid)) => deviceUuid + 2
case Right(Right(carSerialId)) => carSerialId + 3
}
getUserIdOrDeviceIdOrCarSerialId(Left(taggedUserId))
getUserIdOrDeviceIdOrCarSerialId(Right(Left(taggedDeviceUuid)))
getUserIdOrDeviceIdOrCarSerialId(Right(Right(taggedCarSerialId)))
// You can do by Coproduct by shapeless
import shapeless.{Coproduct, CNil, :+:, Inl, Inr}
type Id = UserId :+: DeviceUuid :+: CarSerialId :+: CNil
def getId(id: Id): Long = id match {
case Inl(userId) => userId + 1
case Inr(Inl(deviceUuid)) => deviceUuid + 2
case Inr(Inr(Inl(carSerialId))) => carSerialId + 3
case Inr(Inr(Inr(cNil))) => 0
}
getId(Coproduct[Id](taggedUserId))
getId(Coproduct[Id](taggedDeviceUuid))
getId(Coproduct[Id](taggedCarSerialId))
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