protected function _fetchDisplayFrontdoor()
{
$displayName = $this->getDisplayName('frontdoor');
$parentId = $this->getParentNodeId();
if (!empty($parentId)) {
$parent = new Opus_Collection($parentId);
$parentDisplayName = $parent->getDisplayFrontdoor();
// implicitly calls $parent->_fetchDisplayFrontdoor()
if (!empty($parentDisplayName)) {
$displayName = $parentDisplayName . ' / ' . $displayName;
}
}
return $displayName;
}