Question

How to programmatically determine if the given class is a case class or a simple class?

Answer 1

Currently (2011), you can use reflection to find out if the class implements the interface scala.Product:

scala> def isCaseClass(o: AnyRef) = o.getClass.getInterfaces.find(_ == classOf[scala.Product]) != None
isCaseClass: (o: AnyRef)Boolean

scala> isCaseClass(Some(1))
res3: Boolean = true

scala> isCaseClass("")
res4: Boolean = false

This is just an approximation – you could go further and check if it has a copy method, if it implements Serializable, if it has a companion object with an appropriate apply or unapply method – in essence, check for all the things expected from a case class using reflection.

The scala reflection package coming in one of the next releases should make case class detection easier and more precise.

EDIT:

You can now do it using the new Scala Reflection library — see other answer.