public function isLocked()
    {
        $result = false;
        if(!$this->isNew())
        {
            if(isset($this->locked_on) && isset($this->locked_by))
            {
                $locked  = strtotime($this->locked_on);
                $current = strtotime(gmdate('Y-m-d H:i:s'));

                //Check if the lock has gone stale
                if($current - $locked < $this->_lifetime)
                {
                    $userid = $this->getObject('user')->getId();
                    if($this->locked_by != 0 && $this->locked_by != $userid) {
                        $result= true;
                    }
                }
            }
        }

        return $result;
    }