getBool (Function)

Function retrieves the boolean value specified in the given path of the JSON element.

Syntax

<BOOL> json:getBool(<STRING|OBJECT> json, <STRING> path)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
json	The JSON input containing a boolean value.		STRING OBJECT	No	Yes
path	The JSON path to fetch the boolean value.		STRING	No	Yes

Example 1

@info(name = 'query1')
json:getBool(json,'$.married')

The json:getBool(json,'$.married') function attempts to find a boolean value in the JSON object json at the path $.married. If the value exists and is a boolean, the function will return that value. For instance, given a JSON object like {'name' : 'John', 'married' : true}, this function would return true.

Example 2

@info(name = 'query1')
json:getBool(json,'$.name')

The json:getBool(json,'$.name') function tries to find a boolean value in the JSON object json at the path $.name. If the value exists and is a boolean, the function will return that value. However, if the value at the specified path is not a boolean or doesn't exist, the function will return null. For instance, given a JSON object like {'name' : 'John', 'married' : true}, this function would return null because the value at $.name is a string, not a boolean.

Example 3

@info(name = 'query1')
json:getBool(json,'$.foo')

The json:getBool(json,'$.foo') function attempts to find a boolean value in the JSON object json at the path $.foo. If the value exists and is a boolean, the function will return that value. However, if the value at the specified path does not exist or is not a boolean, the function will return null. For instance, given a JSON object like {'name' : 'John', 'married' : true}, this function would return null because there is no foo key in the JSON object.

Example 4

CREATE STREAM PersonStream (json string);
CREATE SINK STREAM MarriedPersonStream (name string, married bool);

@info(name = 'ExtractMaritalStatus')
INSERT INTO MarriedPersonStream
SELECT json:getString(json, '$.name') AS name, json:getBool(json, '$.married') AS married
FROM PersonStream WINDOW TUMBLING_LENGTH(1);

In this example, two streams are defined: PersonStream for input data and MarriedPersonStream for the output.

The ExtractMaritalStatus query listens for events from the PersonStream. Each event is a JSON string representing a person's details.

The json:getString(json, '$.name') and json:getBool(json, '$.married') functions are used to extract the name (a string) and marital status (a boolean) from each JSON string. These extracted values are then inserted into the MarriedPersonStream.

The query continuously processes each person's details from PersonStream, extracts the name and marital status, and feeds these values into the MarriedPersonStream.