validateanyProduct.scala

validateanyProduct.scala

// modify to collect errors, use Either or whatever floats your boat, just an example that throws 
// IllegalArgumentException on the first null or empty String it encounters, if there is one.
// Works for any case class or collection such as List.

def validateProduct[T <: Product](product: T): Unit = product.productIterator foreach {
  case null => throw new IllegalArgumentException("null attributes are not allowed for " + product)
  case x: String if x.isEmpty => throw new IllegalArgumentException("Empty strings are not allowed for " + product)
  case x: Product => validateProduct(x)
  case _ => {}
}

Whenever you have isInstanceOf and asInstanceOf together, type-casing in pattern-matching can make code slightly clearer.

def validateProduct[T <: Product](product: T): Unit = product.productIterator foreach {
  case null => throw new IllegalArgumentException("null attributes are not allowed for " + product)
  case x: String if x.isEmpty => throw new IllegalArgumentException("Empty strings are not allowed for " + product)
  case x: Product => validateProduct(x)
  case _ => ()
}

EDIT: Added the default case.

Cheers! As always, you point out good things. :)

NP. :)