public function update_options($options = null) {
        global $DB;
        $classname = 'repository_' . $this->_typename;
        $instanceoptions = repository::static_function($this->_typename, 'get_instance_option_names');
        if (empty($instanceoptions)) {
            // update repository instance name if this plugin type doesn't have muliti instances
            $params = array();
            $params['type'] = $this->_typename;
            $instances = repository::get_instances($params);
            $instance = array_pop($instances);
            if ($instance) {
                $DB->set_field('repository_instances', 'name', $options['pluginname'], array('id'=>$instance->id));
            }
            unset($options['pluginname']);
        }

        if (!empty($options)) {
            $this->_options = $options;
        }

        foreach ($this->_options as $name => $value) {
            set_config($name, $value, $this->_typename);
        }

        cache::make('core', 'repositories')->purge();
        return true;
    }