public static function getInstance($dataType) { if (!isset(self::$connections[$dataType])) { try { $connection = new Mongo(Config::item('env.mongodb.server'), Config::item('env.mongodb.option')); } catch (MongoConnectionException $e) { $connection = new BlackHole(); return self::$connections[$dataType] = $connection; } self::$connections[$dataType] = $connection->selectDB('chaoge')->selectCollection($dataType); self::$connections[$dataType]->setSlaveOkay(); } return self::$connections[$dataType]; }