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API Docs - v2.0.6

Tested Siddhi Core version: 5.1.13

It could also support other Siddhi Core minor versions.

Json

group (Aggregate Function)

This function aggregates the JSON elements and returns a JSON object by adding enclosing.element if it is provided. If enclosing.element is not provided it aggregate the JSON elements returns a JSON array.

Syntax

<OBJECT> json:group(<STRING|OBJECT> json)
<OBJECT> json:group(<STRING|OBJECT> json, <BOOL> distinct)
<OBJECT> json:group(<STRING|OBJECT> json, <STRING> enclosing.element)
<OBJECT> json:group(<STRING|OBJECT> json, <STRING> enclosing.element, <BOOL> distinct)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON element that needs to be aggregated.

STRING
OBJECT
No Yes
enclosing.element

The JSON element used to enclose the aggregated JSON elements.

EMPTY_STRING STRING Yes Yes
distinct

This is used to only have distinct JSON elements in the concatenated JSON object/array that is returned.

false BOOL Yes Yes

Examples EXAMPLE 1

from InputStream#window.length(5)
select json:group("json") as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"12:20"}, it returns [{"date":"2013-11-19","time":"10:30"}{"date":"2013-11-19","time":"12:20"}] to the 'OutputStream'.

EXAMPLE 2

from InputStream#window.length(5)
select json:group("json", true) as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"10:30"}, it returns [{"date":"2013-11-19","time":"10:30"}] to the 'OutputStream'.

EXAMPLE 3

from InputStream#window.length(5)
select json:group("json", "result") as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"12:20"}, it returns {"result":[{"date":"2013-11-19","time":"10:30"},{"date":"2013-11-19","time":"12:20"}} to the 'OutputStream'.

EXAMPLE 4

from InputStream#window.length(5)
select json:group("json", "result", true) as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"10:30"}, it returns {"result":[{"date":"2013-11-19","time":"10:30"}]} to the 'OutputStream'.

groupAsObject (Aggregate Function)

This function aggregates the JSON elements and returns a JSON object by adding enclosing.element if it is provided. If enclosing.element is not provided it aggregate the JSON elements returns a JSON array.

Syntax

<OBJECT> json:groupAsObject(<STRING|OBJECT> json)
<OBJECT> json:groupAsObject(<STRING|OBJECT> json, <BOOL> distinct)
<OBJECT> json:groupAsObject(<STRING|OBJECT> json, <STRING> enclosing.element)
<OBJECT> json:groupAsObject(<STRING|OBJECT> json, <STRING> enclosing.element, <BOOL> distinct)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON element that needs to be aggregated.

STRING
OBJECT
No Yes
enclosing.element

The JSON element used to enclose the aggregated JSON elements.

EMPTY_STRING STRING Yes Yes
distinct

This is used to only have distinct JSON elements in the concatenated JSON object/array that is returned.

false BOOL Yes Yes

Examples EXAMPLE 1

from InputStream#window.length(5)
select json:groupAsObject("json") as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"12:20"}, it returns [{"date":"2013-11-19","time":"10:30"}{"date":"2013-11-19","time":"12:20"}] to the 'OutputStream'.

EXAMPLE 2

from InputStream#window.length(5)
select json:groupAsObject("json", true) as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"10:30"}, it returns [{"date":"2013-11-19","time":"10:30"}] to the 'OutputStream'.

EXAMPLE 3

from InputStream#window.length(5)
select json:groupAsObject("json", "result") as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"12:20"}, it returns {"result":[{"date":"2013-11-19","time":"10:30"},{"date":"2013-11-19","time":"12:20"}} to the 'OutputStream'.

EXAMPLE 4

from InputStream#window.length(5)
select json:groupAsObject("json", "result", true) as groupedJSONArray
input OutputStream;

When we input events having values for the json as {"date":"2013-11-19","time":"10:30"} and {"date":"2013-11-19","time":"10:30"}, it returns {"result":[{"date":"2013-11-19","time":"10:30"}]} to the 'OutputStream'.

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 boolean value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the boolean value.

STRING No Yes

Examples EXAMPLE 1

json:getBool(json,'$.married')

If the json is the format {'name' : 'John', 'married' : true}, the function returns true as there is a matching boolean at $.married.

EXAMPLE 2

json:getBool(json,'$.name')

If the json is the format {'name' : 'John', 'married' : true}, the function returns null as there is no matching boolean at $.name.

EXAMPLE 3

json:getBool(json,'$.foo')

If the json is the format {'name' : 'John', 'married' : true}, the function returns null as there is no matching element at $.foo.

getDouble (Function)

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

Syntax

<DOUBLE> json:getDouble(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing double value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the double value.

STRING No Yes

Examples EXAMPLE 1

json:getDouble(json,'$.salary')

If the json is the format {'name' : 'John', 'salary' : 12000.0}, the function returns 12000.0 as there is a matching double at $.salary.

EXAMPLE 2

json:getDouble(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

EXAMPLE 3

json:getDouble(json,'$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching double at $.name.

getFloat (Function)

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

Syntax

<FLOAT> json:getFloat(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing float value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the float value.

STRING No Yes

Examples EXAMPLE 1

json:getFloat(json,'$.salary')

If the json is the format {'name' : 'John', 'salary' : 12000.0}, the function returns 12000 as there is a matching float at $.salary.

EXAMPLE 2

json:getFloat(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

EXAMPLE 3

json:getFloat(json,'$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching float at $.name.

getInt (Function)

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

Syntax

<INT> json:getInt(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing int value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the int value.

STRING No Yes

Examples EXAMPLE 1

json:getInt(json,'$.age')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns 23 as there is a matching int at $.age.

EXAMPLE 2

json:getInt(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

EXAMPLE 3

json:getInt(json,'$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching int at $.name.

getLong (Function)

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

Syntax

<LONG> json:getLong(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing long value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the long value.

STRING No Yes

Examples EXAMPLE 1

json:getLong(json,'$.age')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns 23 as there is a matching long at $.age.

EXAMPLE 2

json:getLong(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

EXAMPLE 3

json:getLong(json,'$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching long at $.name.

getObject (Function)

Function retrieves the object specified in the given path of the JSON element.

Syntax

<OBJECT> json:getObject(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing the object.

STRING
OBJECT
No Yes
path

The JSON path to fetch the object.

STRING No Yes

Examples EXAMPLE 1

json:getObject(json,'$.address')

If the json is the format {'name' : 'John', 'address' : {'city' : 'NY', 'country' : 'USA'}}, the function returns {'city' : 'NY', 'country' : 'USA'} as there is a matching object at $.address.

EXAMPLE 2

json:getObject(json,'$.age')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns 23 as there is a matching object at $.age.

EXAMPLE 3

json:getObject(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

getString (Function)

Function retrieves value specified in the given path of the JSON element as a string.

Syntax

<STRING> json:getString(<STRING|OBJECT> json, <STRING> path)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input containing value.

STRING
OBJECT
No Yes
path

The JSON path to fetch the value.

STRING No Yes

Examples EXAMPLE 1

json:getString(json,'$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns John as there is a matching string at $.name.

EXAMPLE 2

json:getString(json,'$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns null as there are no matching element at $.salary.

EXAMPLE 3

json:getString(json,'$.age')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns 23 as a string as there is a matching element at $.age.

EXAMPLE 4

json:getString(json,'$.address')

If the json is the format {'name' : 'John', 'address' : {'city' : 'NY', 'country' : 'USA'}}, the function returns {'city' : 'NY', 'country' : 'USA'} as a string as there is a matching element at $.address.

isExists (Function)

Function checks whether there is a JSON element present in the given path or not.

Syntax

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

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON input that needs to be searched for an elements.

STRING
OBJECT
No Yes
path

The JSON path to check for the element.

STRING No Yes

Examples EXAMPLE 1

json:isExists(json, '$.name')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns true as there is an element in the given path.

EXAMPLE 2

json:isExists(json, '$.salary')

If the json is the format {'name' : 'John', 'age' : 23}, the function returns false as there is no element in the given path.

setElement (Function)

Function sets JSON element into a given JSON at the specific path.

Syntax

<OBJECT> json:setElement(<STRING|OBJECT> json, <STRING> path, <STRING|BOOL|DOUBLE|FLOAT|INT|LONG|OBJECT> json.element)
<OBJECT> json:setElement(<STRING|OBJECT> json, <STRING> path, <STRING|BOOL|DOUBLE|FLOAT|INT|LONG|OBJECT> json.element, <STRING> key)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The JSON to which a JSON element needs to be added/replaced.

STRING
OBJECT
No Yes
path

The JSON path where the JSON element should be added/replaced.

STRING No Yes
json.element

The JSON element being added.

STRING
BOOL
DOUBLE
FLOAT
INT
LONG
OBJECT
No Yes
key

The key to be used to refer the newly added element in the input JSON.

Assumes the element is added to a JSON array, or the element selected by the JSON path will be updated. STRING Yes Yes

Examples EXAMPLE 1

json:setElement(json, '$', "{'country' : 'USA'}", 'address')

If the json is the format {'name' : 'John', 'married' : true},the function updates the json as {'name' : 'John', 'married' : true, 'address' : {'country' : 'USA'}} by adding 'address' element and returns the updated JSON.

EXAMPLE 2

json:setElement(json, '$', 40, 'age')

If the json is the format {'name' : 'John', 'married' : true},the function updates the json as {'name' : 'John', 'married' : true, 'age' : 40} by adding 'age' element and returns the updated JSON.

EXAMPLE 3

json:setElement(json, '$', 45, 'age')

If the json is the format {'name' : 'John', 'married' : true, 'age' : 40}, the function updates the json as {'name' : 'John', 'married' : true, 'age' : 45} by replacing 'age' element and returns the updated JSON.

EXAMPLE 4

json:setElement(json, '$.items', 'book')

If the json is the format {'name' : 'Stationary', 'items' : ['pen', 'pencil']}, the function updates the json as {'name' : 'John', 'items' : ['pen', 'pencil', 'book']} by adding 'book' in the items array and returns the updated JSON.

EXAMPLE 5

json:setElement(json, '$.item', 'book')

If the json is the format {'name' : 'Stationary', 'item' : 'pen'}, the function updates the json as {'name' : 'John', 'item' : 'book'} by replacing 'item' element and returns the updated JSON.

EXAMPLE 6

json:setElement(json, '$.address', 'city', 'SF')

If the json is the format {'name' : 'John', 'married' : true},the function will not update, but returns the original JSON as there are no valid path for $.address.

toObject (Function)

Function generate JSON object from the given JSON string.

Syntax

<OBJECT> json:toObject(<STRING> json)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

A valid JSON string that needs to be converted to a JSON object.

STRING No Yes

Examples EXAMPLE 1

json:toJson(json)

This returns the JSON object corresponding to the given JSON string.

toString (Function)

Function generates a JSON string corresponding to a given JSON object.

Syntax

<STRING> json:toString(<OBJECT> json)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

A valid JSON object to generates a JSON string.

OBJECT No Yes

Examples EXAMPLE 1

json:toString(json)

This returns the JSON string corresponding to a given JSON object.

tokenize (Stream Processor)

Stream processor tokenizes the given JSON into to multiple JSON string elements and sends them as separate events.

Syntax

json:tokenize(<STRING|OBJECT> json, <STRING> path)
json:tokenize(<STRING|OBJECT> json, <STRING> path, <BOOL> fail.on.missing.attribute)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The input JSON that needs to be tokenized.

STRING
OBJECT
No Yes
path

The path of the set of elements that will be tokenized.

STRING No Yes
fail.on.missing.attribute

If there are no element on the given path, when set to true the system will drop the event, and when set to false the system will pass 'null' value to the jsonElement output attribute.

true BOOL Yes No
Extra Return Attributes
Name Description Possible Types
jsonElement

The JSON element retrieved based on the given path will be returned as a JSON string. If the 'path' selects a JSON array then the system returns each element in the array as a JSON string via a separate events.

STRING

Examples EXAMPLE 1

define stream InputStream (json string, path string);

@info(name = 'query1')
from InputStream#json:tokenizeAsObject(json, path)
select path, jsonElement
insert into OutputStream;

If the input 'json' is {name:'John', enrolledSubjects:['Mathematics', 'Physics']}, and the 'path' is passed as $.enrolledSubjects then for both the elements in the selected JSON array, it generates it generates events as ('$.enrolledSubjects', 'Mathematics'), and ('$.enrolledSubjects', 'Physics').
For the same input JSON, if the 'path' is passed as $.name then it will only produce one event ('$.name', 'John') as the 'path' provided a single JSON element.

EXAMPLE 2

define stream InputStream (json string, path string);

@info(name = 'query1')
from InputStream#json:tokenizeAsObject(json, path, true)
select path, jsonElement
insert into OutputStream;

If the input 'json' is {name:'John', age:25},and the 'path' is passed as $.salary then the system will produce ('$.salary', null), as the 'fail.on.missing.attribute' is true and there are no matching element for $.salary.

tokenizeAsObject (Stream Processor)

Stream processor tokenizes the given JSON into to multiple JSON object elements and sends them as separate events.

Syntax

json:tokenizeAsObject(<STRING|OBJECT> json, <STRING> path)
json:tokenizeAsObject(<STRING|OBJECT> json, <STRING> path, <BOOL> fail.on.missing.attribute)

QUERY PARAMETERS

Name Description Default Value Possible Data Types Optional Dynamic
json

The input JSON that needs to be tokenized.

STRING
OBJECT
No Yes
path

The path of the set of elements that will be tokenized.

STRING No Yes
fail.on.missing.attribute

If there are no element on the given path, when set to true the system will drop the event, and when set to false the system will pass 'null' value to the jsonElement output attribute.

true BOOL Yes No
Extra Return Attributes
Name Description Possible Types
jsonElement

The JSON element retrieved based on the given path will be returned as a JSON object. If the 'path' selects a JSON array then the system returns each element in the array as a JSON object via a separate events.

OBJECT

Examples EXAMPLE 1

define stream InputStream (json string, path string);

@info(name = 'query1')
from InputStream#json:tokenizeAsObject(json, path)
select path, jsonElement
insert into OutputStream;

If the input 'json' is {name:'John', enrolledSubjects:['Mathematics', 'Physics']}, and the 'path' is passed as $.enrolledSubjects then for both the elements in the selected JSON array, it generates it generates events as ('$.enrolledSubjects', 'Mathematics'), and ('$.enrolledSubjects', 'Physics').
For the same input JSON, if the 'path' is passed as $.name then it will only produce one event ('$.name', 'John') as the 'path' provided a single JSON element.

EXAMPLE 2

define stream InputStream (json string, path string);

@info(name = 'query1')
from InputStream#json:tokenizeAsObject(json, path, true)
select path, jsonElement
insert into OutputStream;

If the input 'json' is {name:'John', age:25},and the 'path' is passed as $.salary then the system will produce ('$.salary', null), as the 'fail.on.missing.attribute' is true and there are no matching element for $.salary.