Scala Implicit Example

ImplicitExample.scala

object Example {

  trait DataSet {
    def name: String
  }

  case class SubreadSet(name: String) extends DataSet
  case class AlignSet(name: String) extends DataSet
  case class RefSet(name: String) extends DataSet

  trait Loader[T <: DataSet] {
    def load(ds: String): T
  }

  implicit object LoadSubreadSet extends Loader[SubreadSet] {
    def load(ds: String) = SubreadSet(ds)
  }
  implicit object LoadAlignSet extends Loader[AlignSet] {
    def load(ds: String) = AlignSet(ds)
  }
  implicit object LoadRefSet extends Loader[RefSet] {
    def load(ds: String) = RefSet(ds)
  }

  def loader[T <: DataSet](ds: String)(implicit loader: Loader[T]) = loader.load(ds)


  trait Validator[T <: DataSet] {
    def validate(ds: T): Boolean
  }

  implicit object ValidateSubreadSet extends Validator[SubreadSet] {
    override def validate(subreadSet: SubreadSet): Boolean = true
  }
  implicit object ValidateReferenceSet extends Validator[RefSet] {
    override def validate(refSet: RefSet) = false
  }
  implicit object ValidateAlignSet extends Validator[AlignSet] {
    override def validate(ds: AlignSet): Boolean = true
  }

  def validator[T <: DataSet](ds: T)(implicit vx: Validator[T]) = vx.validate(ds)


  def runDemo = {

    val sx = "SubreadSet-1234"

    val s1 = loader[SubreadSet](sx)

    println(s"SubreadSet loaded $s1 is valid? ${validator(s1)}")

    val s = SubreadSet("SubreadSet")
    val a = AlignSet("AlignSet")
    val r = RefSet("RefSet")

    println(s"${s} is valid? ${validator(s)}")
    println(s"${a} is valid? ${validator(a)}")
    println(s"${r} is valid? ${validator(r)}")

  }


}