public function val($val = null) {
		$val = (int) $val;
		if ($val) {
			if (is_numeric($val) && is_int($val*1)) {
				if (in_array($this->sources[$val],$this->sources)) {
					$this->val = $val;
					return $this->val;
				}
			} else {
				throw new \SimplOn\DataValidationException($this->valudationNaN);
			}
		} else {
			return $this->val;
		}
	}