toJSON (Function)

Function converts a map into a JSON object and returns the JSON as a string.

Syntax

<STRING> map:toJSON(<OBJECT> map)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
map	The map that needs to be converted to JSON		OBJECT	No	Yes

Example 1

map:toJSON(company)

The map:toJSON(company) function is used to transform the company map, which consists of key-value pairs such as (symbol:gdn), (volume : 100), and (price, 200), into a JSON formatted string: {"symbol" : "gdn", "volume" : 100 , "price" : 200}.

Example 2

CREATE STREAM CompanyInput (symbol string, volume int, price float, company object);
CREATE SINK STREAM CompanyJson (companyJson string);

@info(name = 'TransformCompanyToJson')
INSERT INTO CompanyJson
SELECT map:toJSON(company) AS companyJson
FROM CompanyInput WINDOW TUMBLING_LENGTH(10);

In this stream processing example, the CompanyInput stream is created to provide input to the query, and the CompanyJson stream is created to collect the output.

The CompanyInput stream includes details about the company (symbol, volume, price) and a company map. The TransformCompanyToJson query listens for batches of 10 events from the CompanyInput stream.

The map:toJSON(company) function is used to transform the company map of each batch into a JSON formatted string. This string, referred to as companyJson, is then inserted into the CompanyJson stream.

This way, the query continuously transforms batches of company map details into JSON strings and sends these strings to the CompanyJson stream.