public function checkUserExistenceByUsername($username, $parentGroupName = null)
{
if ($parentGroupName) {
// find parent group name
$searchResults = $this->searchUserGroups($parentGroupName);
if (empty($searchResults)) {
// group not found, so return immediately
return false;
}
$groupId = $searchResults[0]->valueObject->contentInfo->id;
} else {
$groupId = null;
}
$searchResults = $this->searchUserByLogin($username, $groupId);
return empty($searchResults) ? false : true;
}