containsKey (Function)

Function checks if the map contains the key.

Syntax

<BOOL> map:containsKey(<OBJECT> map, <INT|LONG|FLOAT|DOUBLE|BOOL|STRING> key)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
map	The map the needs to be checked on containing the key or not.		OBJECT	No	Yes
key	The key to be checked.		INT LONG FLOAT DOUBLE BOOL STRING	No	Yes

Example 1

map:containsKey(stockDetails, '1234')

The map:containsKey(stockDetails, '1234') function checks whether the stockDetails map contains a specific key, which is '1234' in this case. If the key is present in the map, the function returns true, otherwise, it returns false. This allows for efficient verification of key presence in a map without the need to traverse or inspect the entire map.

Example 2

CREATE STREAM InputMapStream (id string, stockDetails object);
CREATE SINK STREAM OutputKeyPresenceStream (id string, keyPresence bool);

@info(name = 'KeyPresenceCheck')
INSERT INTO OutputKeyPresenceStream
SELECT id, map:containsKey(stockDetails, '1234') AS keyPresence
FROM InputMapStream;

In this stream worker named KeyPresenceCheck, InputMapStream is created to provide input to the query, which includes an identifier (id) and a map (stockDetails). A sink stream, OutputKeyPresenceStream, is created to collect the output, which includes the identifier and a boolean value indicating the presence of a specific key in the map.

The query processes events from InputMapStream, using the map:containsKey(stockDetails, '1234') function to check whether the stockDetails map in each event contains the key '1234'. The resulting boolean value, along with the identifier, is then inserted into OutputKeyPresenceStream. This approach provides real-time checking of key presence in maps within a data stream.