private function setDecisionStrategy()
    {
        $strategy = $this->config->get('DecisionStrategy', 'unanimous');
        if ($strategy != self::VOTER_STR_AFFIRMATIVE && $strategy != self::VOTER_STR_CONSENSUS && $strategy != self::VOTER_STR_UNANIMOUS
        ) {

            throw new AccessControlException('Invalid access control decision strategy "' . $strategy . '"');
        }

        $this->strategy = $strategy;
    }