Java like なビルダーパターンのサンプル

ObjectCreationBuilderJavaLikeSample.scala

class NutrionFacts(builder: NutrionFacts.Builder) {
  val servingSize: Int  = builder.servingSize
  val sergings: Int     = builder.sergings
  val calories: Int     = builder.calories
  val fat: Int          = builder.fat
  val sodium: Int       = builder.sodium
  val carbohydrate: Int = builder.carbohydrate
}

object NutrionFacts {
  class Builder {
    var servingSize: Int
    var sergings: Int
    var calories     = 0
    var fat          = 0
    var sodium       = 0
    var carbohydrate = 0

    def setServingSize(servingSize: Int): Builder = {
      this.sergingSize = sergingSize
      this
    }

    def setServings(servings: Int): Builder = {
      this.sergings = sergings
      this
    }

    def setCalories(calories: Int): Builder = {
      this.calories = calories
      this
    }

    def setFat(fat: Int): Builder = {
      this.fat = fat
      this
    }

    def setSodium(sodium: Int): Builder = {
      this.sodium = sodium
      this
    }

    def setCarbohydrate(carbohydratre: Int) = {
      this.carbohydrate = carbohydrate
      this
    }

    def build = new NutrionFacts(this)
  }
}