Making a Scala version of this Java method

Instead of navigating the tracks to find the value you want lanes find (_.number == 42)

.

Express guards as filters and defaults as getOrElse

.

Example:

scala> case class Lane(number: Int)
defined class Lane

scala> val lanes: Seq[Lane] = Nil
lanes: Seq[Lane] = List()

scala> Option(lanes) filter (_.nonEmpty) flatMap (_.find(_.number == 42))
res0: Option[Lane] = None

scala> Option(lanes) filter (_.nonEmpty) flatMap (_.find(_.number == 42)) map (_.number) getOrElse -1
res1: Int = -1

      

        
        
        
      

    

or

scala> for (x <- Option(lanes); y <- x.find(_.number == 42)) yield y.number
res3: Option[Int] = None

      

        
        
        
      

    

Then refactor predicates to small functions for getting x find goodNumber

, etc.

More reviews:

Folding is commendable, but usually you want to use max

or maxBy

if that's what you do.

spots maxBy (_.name.toInt)

      

        
        
        
      

    

You can express your missing condition as part of a fold, but it's easier to just scan the list again:

if (spots exists (!_.model.equalsIgnoreCase(vehicle.model))) fail

      

        
        
        
      

    

You can optimize later if needed.