1  
   2  object BuilderPattern {
   3    sealed abstract class Preparation
   4    case object Neat extends Preparation
   5    case object OnTheRocks extends Preparation
   6    case object WithWater extends Preparation
   7  
   8    sealed abstract class Glass
   9    case object Short extends Glass
  10    case object Tall extends Glass
  11    case object Tulip extends Glass
  12  
  13    case class OrderOfScotch private[BuilderPattern] (val brand:String, val mode:Preparation, val isDouble:Boolean, val glass:Option[Glass])
  14  
  15    abstract class TRUE  
  16    abstract class FALSE
  17  
  18    abstract class ScotchBuilder { self:ScotchBuilder =>
  19      protected[BuilderPattern] val theBrand:Option[String]
  20      protected[BuilderPattern] val theMode:Option[Preparation]
  21      protected[BuilderPattern] val theDoubleStatus:Option[Boolean]
  22      protected[BuilderPattern] val theGlass:Option[Glass]
  23  
  24      type HAS_BRAND
  25      type HAS_MODE
  26      type HAS_DOUBLE_STATUS
  27  
  28      def withBrand(b:String) = new ScotchBuilder {
  29        protected[BuilderPattern] val theBrand:Option[String] = Some(b)
  30        protected[BuilderPattern] val theMode:Option[Preparation] = self.theMode
  31        protected[BuilderPattern] val theDoubleStatus:Option[Boolean] = self.theDoubleStatus
  32        protected[BuilderPattern] val theGlass:Option[Glass] = self.theGlass
  33  
  34        type HAS_BRAND = TRUE
  35        type HAS_MODE = self.HAS_MODE
  36        type HAS_DOUBLE_STATUS = self.HAS_DOUBLE_STATUS
  37      }
  38  
  39      def withMode(p:Preparation) = new ScotchBuilder {
  40        protected[BuilderPattern] val theBrand:Option[String] = self.theBrand
  41        protected[BuilderPattern] val theMode:Option[Preparation] = Some(p)
  42        protected[BuilderPattern] val theDoubleStatus:Option[Boolean] = self.theDoubleStatus
  43        protected[BuilderPattern] val theGlass:Option[Glass] = self.theGlass
  44  
  45        type HAS_BRAND = self.HAS_BRAND
  46        type HAS_MODE = TRUE
  47        type HAS_DOUBLE_STATUS = self.HAS_DOUBLE_STATUS
  48      }
  49  
  50  
  51      def isDouble(b:Boolean) = new ScotchBuilder {
  52        protected[BuilderPattern] val theBrand:Option[String] = self.theBrand
  53        protected[BuilderPattern] val theMode:Option[Preparation] = self.theMode
  54        protected[BuilderPattern] val theDoubleStatus:Option[Boolean] = Some(b)
  55        protected[BuilderPattern] val theGlass:Option[Glass] = self.theGlass
  56  
  57        type HAS_BRAND = self.HAS_BRAND
  58        type HAS_MODE = self.HAS_MODE
  59        type HAS_DOUBLE_STATUS = TRUE
  60      }
  61       
  62      def withGlass(g:Glass) = new ScotchBuilder {
  63        protected[BuilderPattern] val theBrand:Option[String] = self.theBrand
  64        protected[BuilderPattern] val theMode:Option[Preparation] = self.theMode
  65        protected[BuilderPattern] val theDoubleStatus:Option[Boolean] = self.theDoubleStatus
  66        protected[BuilderPattern] val theGlass:Option[Glass] = Some(g)
  67  
  68        type HAS_BRAND = self.HAS_BRAND
  69        type HAS_MODE = self.HAS_MODE
  70        type HAS_DOUBLE_STATUS = self.HAS_DOUBLE_STATUS
  71      }
  72  
  73    }
  74  
  75    type CompleteBuilder = ScotchBuilder {
  76      type HAS_BRAND = TRUE
  77      type HAS_MODE = TRUE
  78      type HAS_DOUBLE_STATUS = TRUE
  79    }
  80  
  81    implicit def enableBuild(builder:CompleteBuilder) = new {
  82      def build() = 
  83        new OrderOfScotch(builder.theBrand.get, builder.theMode.get, builder.theDoubleStatus.get, builder.theGlass);
  84    }
  85  
  86    def builder = new ScotchBuilder {
  87      protected[BuilderPattern] val theBrand:Option[String] = None
  88      protected[BuilderPattern] val theMode:Option[Preparation] = None
  89      protected[BuilderPattern] val theDoubleStatus:Option[Boolean] = None
  90      protected[BuilderPattern] val theGlass:Option[Glass] = None
  91  
  92      type HAS_BRAND = FALSE
  93      type HAS_MODE = FALSE
  94      type HAS_DOUBLE_STATUS = FALSE
  95    }
  96  }