josep2

import org.apache.spark.sql.expressions.MutableAggregationBuffer
import org.apache.spark.sql.expressions.UserDefinedAggregateFunction
import org.apache.spark.sql.Row
import org.apache.spark.sql.types._

class HarmonicMean extends UserDefinedAggregateFunction {
  
  // Defind the schema of the input data
  override def inputSchema: org.apache.spark.sql.types.StructType =
    StructType(StructField("value", DoubleType) :: Nil)

josep2

  case class ConnectMessage(deviceId: Long)
  case object DisconnectMessage
  case object VolumeAdjustmentMessage
  case object PauseMessage
  
  class BluetoothHeadphones extends Actor {
    def receive = {
      case ConnectMessage(message) =>
      case DisconnectMessage =>
      case VolumeAdjustmentMessage =>

josep2

sealed abstract class Action extends Product with Serializable

  object Camera {
    final case class Picture(iso: Int, aperture: Double) extends Action
    final case class Video (duration: Int) extends Action
  }

  def actionHandler(action: Action): Unit = action match {
    case Camera.Picture(iso, app) => print(s"Took photo with iso: $iso and aperture $app")
    case Camera.Video(dur) => print(s"Took video for $dur seconds")

josep2

case class Watch(mechanism: String)

val swissWatch = Watch("swiss")

println(swissWatch)

// Watch(swiss)

josep2

case class Album(title: String, year: Int)

val bitusa = Album("Born in the USA", 1980)

val bitusaRemaster = Album.copy(year = 1991)

josep2

case class Player(name: String)

val biggie = Player("Biggie")

biggie.name = "2pac"

// error: reassignment to val

josep2

case class Drink(name: String)

val henny = Drink("henny")

val henny2 = henny.copy()

println(henny.equals(henny2))

//true

josep2

  sealed trait Topping
  case object RefriedBeans extends Topping
  case object Onions extends Topping
  case object Lettuce extends Topping
  case object Salsa extends Topping

  sealed trait Shell
  case object CornTortilla extends Shell
  case object TortillaChips extends Shell
  case object FlourTortilla extends Shell

josep2

// from https://blog.codecentric.de/en/2016/07/spark-2-0-datasets-case-classes/
final case class Body(id: Int, 
                      width: Double, 
                      height: Double, 
                      depth: Double, 
                      material: String, 
                      color: String)
 
val ds = df.as[Body]

josep2

// From https://github.com/spray/spray-json
case class Color(name: String, red: Int, green: Int, blue: Int)

object MyJsonProtocol extends DefaultJsonProtocol {
  implicit val colorFormat = jsonFormat4(Color)
}

import MyJsonProtocol._
import spray.json._