Scalazのminimum/maximumならOptionが返るから安心

Sample

object Sample extends App {

  val seq = Seq(1, 2, 3)
  val empty = Seq[Int]()

  println(seq.max)    // -> 3
//  println(empty.max)  // -> java.lang.UnsupportedOperationException: empty.max

  import scalaz._, Scalaz._

  println(seq.maximum)    // -> Some(3)
  println(empty.maximum)  // -> None

}