Trading

package com.template

import scala.util.Random

object Trading extends App {
  val Sell = "sell"
  val Buy = "buy"

  trait Id {
    def id: Int
  }

  trait Order {
    def quantity: Int
  }

  case class BuyOrder(id: Int, quantity: Int) extends Order with Id

  case class SellOrder(id: Int, quantity: Int) extends Order with Id

  def mkOrder(side: String, qty: Int) =
    if (side.equals(Sell)) SellOrder(mkId, qty) else BuyOrder(mkId, qty)

  def mkId: Int = Random.nextInt()
  
  println(mkOrder("buy", 100))

}