いつものやつ

gistfile1.scala

def toDate[A:DateMagnet](x:A) = implicitly[DateMagnet[A]].convert(x)
 
trait DateMagnet[A]{
  type Result
  def convert(x:A):Result
}
 
object DateMagnet {
  implicit def fromInt = new DateMagnet[(Int, Int, Int)] {
    type Result = java.util.Calendar
    def convert(tuple:(Int, Int, Int)):Result  = {
      val (year, month, date) = tuple
      val c = java.util.Calendar.getInstance
      c.set(year, month - 1, date, 0, 0, 0)
      c
    }
  }
 
  implicit def fromString = new DateMagnet[String] {
    type Result = java.util.Date
    def convert(s:String):Result  =
      (new java.text.SimpleDateFormat("yyyy/MM/dd")).parse(s)
  }
}