code: private static void checkNumericIndex(long index) {
  		if (index > Integer.MAX_VALUE) {
  			throw EvaluationException.create(MSG_INDEX_EXCEEDS_MAXIMUM, index,
  					Integer.MAX_VALUE);
  		} else if (index < Integer.MIN_VALUE) {
  			throw EvaluationException.create(MSG_INDEX_BELOW_MINIMUM, index,
  					Integer.MIN_VALUE);
  		}
  	}
docs: An internal method to check that a numeric index is valid. It must be a
  non-negative integer.
  
  @param index
  @return validated index as an Integer