Design patterns exercise: decorator, simple factory

SandwichShop.scala

object SandwichShop {

  trait Sandwich {
    def getPrice: Double
    def getIngredients: Array[String]
  }

  class CheeseSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2
    override def getIngredients: Array[String] = Array[String]("bread", "cheese")
  }

  class CheeseMayoSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2.5
    override def getIngredients: Array[String] = Array[String]("bread", "cheese", "mayonnaise")
  }

  class CheeseVegetableSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2.5
    override def getIngredients: Array[String] = Array[String]("bread", "cheese", "lettuce", "carrots", "tomatoes")
  }

  class CheeseMayoVegetableSandwich extends SandwichShop.Sandwich {
    override def getPrice = 3
    override def getIngredients: Array[String] = Array[String]("bread", "cheese", "mayonnaise", "lettuce", "carrots", "tomatoes")
  }

  class HamSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2
    override def getIngredients: Array[String] = Array[String]("bread", "ham")
  }

  class HamMayoSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2.5
    override def getIngredients: Array[String] = Array[String]("bread", "ham", "mayonnaise")
  }

  class HamVegetableSandwich extends SandwichShop.Sandwich {
    override def getPrice = 2.5
    override def getIngredients: Array[String] = Array[String]("bread", "ham", "lettuce", "carrots", "tomatoes")
  }

  class HamMayoVegetableSandwich extends SandwichShop.Sandwich {
    override def getPrice = 3
    override def getIngredients: Array[String] = Array[String]("bread", "ham", "mayonnaise", "lettuce", "carrots", "tomatoes")
  }

  def main(args: Array[String]): Unit = {
    val order = Array("cheese", "cheese with mayo", "ham with vegetables")
    var total = 0.0

    for (item <- order) {
      var s = null : Sandwich
      item match {
        case "cheese" =>
          s = new SandwichShop.CheeseSandwich
        case "cheese with mayo" =>
          s = new SandwichShop.CheeseMayoSandwich
        case "cheese with vegetables" =>
          s = new SandwichShop.CheeseVegetableSandwich
        case "cheese with mayo and vegetables" =>
          s = new SandwichShop.CheeseMayoVegetableSandwich
        case "ham" =>
          s = new SandwichShop.HamSandwich
        case "ham with mayo" =>
          s = new SandwichShop.HamMayoSandwich
        case "ham with vegetables" =>
          s = new SandwichShop.HamVegetableSandwich
        case "ham with mayo and vegetables" =>
          s = new SandwichShop.HamMayoVegetableSandwich
      }
      total += s.getPrice
    }

    System.out.println("Total price of order: " + total + " Eur")
  }
}