public static function factory($index, $driver = null)
	{
		if (null === $driver) {
			$driver = Config::get('search.default', 'zend');
		}
		
		switch ($driver) {
			case 'algolia':
				return new Index\Algolia($index, 'algolia');
				
			case 'elasticsearch':
				return new Index\Elasticsearch($index, 'elasticsearch');
				
			case 'zend':
			default:
				return new Index\Zend($index, 'zend');
		}
	}