public function getValidator() {
        if (!$this->_validator instanceof xPDOValidator) {
            $validatorClass = $this->getOption(xPDO::OPT_VALIDATOR_CLASS, null, 'xPDO\\Validation\\xPDOValidator');
            if ($validatorClass = $this->xpdo->loadClass($validatorClass, '', false, true)) {
                $this->_validator = new $validatorClass($this);
            }
        }
        return $this->_validator;
    }