public function getGroups()
    {
        if ($this->_oGroups == null && ($sOxid = $this->getId())) {
            // user groups
            $this->_oGroups = oxNew('oxlist', 'oxgroups');
            $sViewName = getViewName("oxgroups", $this->getLanguage());

            // performance
            $sSelect = "select {$sViewName}.* from {$sViewName}, oxobject2group
                        where oxobject2group.oxobjectid = '{$sOxid}'
                        and oxobject2group.oxgroupsid={$sViewName}.oxid ";
            $this->_oGroups->selectString($sSelect);
        }

        return $this->_oGroups;
    }