public function __sleep()
{
$exprops = array();
$cn = __CLASS__;
if (!$this->_parameterNames or !$this->_parameterNames->getCount()) {
$exprops[] = "{$cn}_parameterNames";
}
if (!$this->_parameterValues or !$this->_parameterValues->getCount()) {
$exprops[] = "{$cn}_parameterValues";
}
return array_diff(parent::__sleep(), $exprops);
}