protected function getSingleKeyValue($actionKey) {
    $query = new ObjectQuery($this->entityType, __CLASS__.__METHOD__);
    $tpl = $query->getObjectTemplate($this->entityType);
    $actionKeyParams = ActionKey::parseKey($actionKey);
    $tpl->setValue($this->valueMap['resource'], Criteria::asValue('=', $actionKeyParams['resource']));
    $tpl->setValue($this->valueMap['context'], Criteria::asValue('=', $actionKeyParams['context']));
    $tpl->setValue($this->valueMap['action'], Criteria::asValue('=', $actionKeyParams['action']));
    $keys = $query->execute(BuildDepth::SINGLE);
    if (sizeof($keys) > 0) {
      return $keys[0]->getValue($this->valueMap['value']);
    }
    return null;
  }