public function listVersions($contentId)
{
$rows = $this->contentGateway->listVersions($contentId);
if (empty($rows)) {
return array();
}
$idVersionPairs = array_map(function ($row) use($contentId) {
return array('id' => $contentId, 'version' => $row['ezcontentobject_version_version']);
}, $rows);
$nameRows = $this->contentGateway->loadVersionedNameData($idVersionPairs);
return $this->contentMapper->extractVersionInfoListFromRows($rows, $nameRows);
}