boolean-to-domain.scala

trait JavaApi {
  def isAuthenticated: Boolean
}

sealed trait IsAuthenticated
object IsAuthenticated {
  def unapply(x: JavaApi): Option[IsAuthenticated] =
    if (x.isAuthenticated) Some(Yes)
    else Some(No)
}

case object Yes extends IsAuthenticated {
  def unapply(x: JavaApi): Option[Yes.type] =
    if (x.isAuthenticated) Some(Yes)
    else None
}

case object No extends IsAuthenticated {
  def unapply(x: JavaApi): Option[No.type] =
    if (x.isAuthenticated) None
    else Some(No)
}

def x: JavaApi =
  new JavaApi {
    override def isAuthenticated = true
  }

def y: JavaApi =
  new JavaApi {
    override def isAuthenticated = false
  }

// YES!
x match {
  case IsAuthenticated(Yes) => println("YES!")
  case IsAuthenticated(No) => println("No. ):")
}

// YES!
x match {
  case Yes(_) => println("YES!")
  case No(_) => println("No. ):")
}

// No. ):
y match {
  case IsAuthenticated(Yes) => println("YES!")
  case IsAuthenticated(No) => println("No. ):")
}

// No. ):
y match {
  case Yes(_) => println("YES!")
  case No(_) => println("No. ):")
}