Maybes是scala的良好模式吗？

Question

For a while I have been struggling to integrate scala with java methods that might return null. I came up with the following utility which helps a lot:

// produce an Option, nulls become None
object Maybe {
    def apply[T](t:T) = if (t==null) None else Some(t)
}

Maybe(javaClass.getResultCouldBeNull()).map( result => doSomeWork(result) )

I have a few questions about this solution:

1. Is there a better or more standard pattern to use?
2. Am I duplicating something that already exists?
3. Does this functionality have hidden gotchas?

Answer 1

Scala's built-in Option is what you're setting out to reinvent.

In that case:

scala> val sOpt: Option[String] = Option(null)
sOpt: Option[String] = None

Answer 2

Why bother making a whole companion object out of it? It's just a function, so you don't need to implement it as an object that looks like a function.

object MyUtilities{
  // a whole bunch of other utilities that you use all over can also be put in this class.
  def maybe[T](t:T) = if (t==null) None else Some(t)
}