public function getStatePersister()
{
if ($this->_statePersister === null) {
$this->_statePersister = Prado::createComponent($this->_statePersisterClass);
if (!$this->_statePersister instanceof IPageStatePersister) {
throw new TInvalidDataTypeException('page_statepersister_invalid');
}
$this->_statePersister->setPage($this);
}
return $this->_statePersister;
}