API Docs - v2.0.2
Tested Siddhi Core version: 5.0.2
It could also support other Siddhi Core minor versions.
Json
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.
Syntaxjson: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 |
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.
Syntaxjson: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 |
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
.