<s> __author__ = '<STR_LIT>' <EOL> from hydro . query_engine import QueryEngine <EOL> from connector_factory import ConnectorHandler <EOL> class QueryEngineFactory ( object ) : <EOL> conn_handler = None <EOL> @ classmethod <EOL> def __get_conn_handler ( cls ) : <EOL> if cls . conn_handler is None : <EOL> cls . conn_handler = ConnectorHandler ( ) <EOL> return cls . conn_handler <EOL> @ classmethod <EOL> def get_query_engine ( cls , engine_type , cache_engine_instance , execution_plan , logger ) : <EOL> cls . __get_conn_handler ( ) . set_logger ( logger ) <EOL> query_engine = QueryEngine ( engine_type , cls . conn_handler , cache_engine_instance , execution_plan , logger ) <EOL> return query_engine </s>
