protected function getBooleanRequestParameter($request, $name, $force = false, $default = null)
    {
        $value = $this->getRequestParameter($request, $name, $force, $default);
        if ('true' === $value || true === $value) {
            $value = true;
        } elseif ('false' === $value || false === $value) {
            $value = false;
        } elseif ($force && true !== $value && false !== $value) {
            throw new ParameterDataTypeException(get_class($this), $name);
        } else {
            $value = $default;
        }

        return $value;
    }