public function setID($id)
    {
        /*
         * TODO validate/tokenize the actual ID
         */
        if (empty((string) $id)) {
            throw new ConfigurationException(
                'The configuration must specify a non-empty (and globally unique) ID for the Tool Provider.',
                ConfigurationException::TOOL_PROVIDER
            );
        } else {
            $this->id = (string) $id;
        }
    }