public function lockAction(Request $request)
    {
        // get request parameters
        $eid = (int) $request->get('eid');
        $language = $request->get('language');

        $elementService = $this->get('phlexible_element.element_service');
        $lockManager = $this->get('phlexible_element.element_lock_manager');

        $element = $elementService->findElement($eid);

        if ($lockManager->isLocked($element)) {
            return new ResultResponse(false, 'Element already locked.');
        } else {
            try {
                // try to lock the element
                $lockManager->lock($element, $this->getUser()->getId());

                return new ResultResponse(true, 'Lock aquired.');
            } catch (\Exception $e) {
                return new ResultResponse(false, $e->getMessage());
            }
        }
    }