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API Docs - v4.3.19¶

Core¶

and (Aggregate Function)¶

Returns the results of AND operation for all the events.

Syntax

<BOOL> and(<BOOL> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be AND operation.		BOOL	No	No

Examples EXAMPLE 1

from cscStream#window.lengthBatch(10)
select and(isFraud) as isFraudTransaction
insert into alertStream;

This will returns the result for AND operation of isFraud values as a boolean value for event chunk expiry by window length batch.

avg (Aggregate Function)¶

Calculates the average for all the events.

Syntax

<DOUBLE> avg(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that need to be averaged.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from fooStream#window.timeBatch
 select avg(temp) as avgTemp
 insert into barStream;

avg(temp) returns the average temp value for all the events based on their arrival and expiry.

count (Aggregate Function)¶

Returns the count of all the events.

Syntax

<LONG> count()

Examples EXAMPLE 1

from fooStream#window.timeBatch(10 sec)
select count() as count
insert into barStream;

This will return the count of all the events for time batch in 10 seconds.

distinctCount (Aggregate Function)¶

This returns the count of distinct occurrences for a given arg.

Syntax

<LONG> distinctCount(<INT|LONG|DOUBLE|FLOAT|STRING> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The object for which the number of distinct occurences needs to be counted.		INT LONG DOUBLE FLOAT STRING	No	No

Examples EXAMPLE 1

from fooStream
select distinctcount(pageID) as count
insert into barStream;

distinctcount(pageID) for the following output returns '3' when the available values are as follows.
"WEB_PAGE_1"
"WEB_PAGE_1"
"WEB_PAGE_2"
"WEB_PAGE_3"
"WEB_PAGE_1"
"WEB_PAGE_2"
The three distinct occurences identified are 'WEB_PAGE_1', 'WEB_PAGE_2', and 'WEB_PAGE_3'.

max (Aggregate Function)¶

Returns the maximum value for all the events.

Syntax

<INT|LONG|DOUBLE|FLOAT> max(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be compared to find the maximum value.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from fooStream#window.timeBatch(10 sec)
select max(temp) as maxTemp
insert into barStream;

max(temp) returns the maximum temp value recorded for all the events based on their arrival and expiry.

maxForever (Aggregate Function)¶

This is the attribute aggregator to store the maximum value for a given attribute throughout the lifetime of the query regardless of any windows in-front.

Syntax

<INT|LONG|DOUBLE|FLOAT> maxForever(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be compared to find the maximum value.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from inputStream
select maxForever(temp) as max
insert into outputStream;

maxForever(temp) returns the maximum temp value recorded for all the events throughout the lifetime of the query.

min (Aggregate Function)¶

Returns the minimum value for all the events.

Syntax

<INT|LONG|DOUBLE|FLOAT> min(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be compared to find the minimum value.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from inputStream
select min(temp) as minTemp
insert into outputStream;

min(temp) returns the minimum temp value recorded for all the events based on their arrival and expiry.

minForever (Aggregate Function)¶

This is the attribute aggregator to store the minimum value for a given attribute throughout the lifetime of the query regardless of any windows in-front.

Syntax

<INT|LONG|DOUBLE|FLOAT> minForever(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be compared to find the minimum value.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from inputStream
select minForever(temp) as max
insert into outputStream;

minForever(temp) returns the minimum temp value recorded for all the events throughoutthe lifetime of the query.

or (Aggregate Function)¶

Returns the results of OR operation for all the events.

Syntax

<BOOL> or(<BOOL> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be OR operation.		BOOL	No	No

Examples EXAMPLE 1

from cscStream#window.lengthBatch(10)
select or(isFraud) as isFraudTransaction
insert into alertStream;

This will returns the result for OR operation of isFraud values as a boolean value for event chunk expiry by window length batch.

stdDev (Aggregate Function)¶

Returns the calculated standard deviation for all the events.

Syntax

<DOUBLE> stdDev(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that should be used to calculate the standard deviation.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from inputStream
select stddev(temp) as stdTemp
insert into outputStream;

stddev(temp) returns the calculated standard deviation of temp for all the events based on their arrival and expiry.

sum (Aggregate Function)¶

Returns the sum for all the events.

Syntax

<LONG|DOUBLE> sum(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The value that needs to be summed.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

from inputStream
select sum(volume) as sumOfVolume
insert into outputStream;

This will returns the sum of volume values as a long value for each event arrival and expiry.

unionSet (Aggregate Function)¶

Union multiple sets.
This attribute aggregator maintains a union of sets. The given input set is put into the union set and the union set is returned.

Syntax

<OBJECT> unionSet(<OBJECT> set)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
set	The java.util.Set object that needs to be added into the union set.		OBJECT	No	No

Examples EXAMPLE 1

from stockStream 
select createSet(symbol) as initialSet 
insert into initStream 

from initStream#window.timeBatch(10 sec) 
select unionSet(initialSet) as distinctSymbols 
insert into distinctStockStream;

distinctStockStream will return the set object which contains the distinct set of stock symbols received during a sliding window of 10 seconds.

UUID (Function)¶

Generates a UUID (Universally Unique Identifier).

Syntax

<STRING> UUID()

Examples EXAMPLE 1

from TempStream
select convert(roomNo, 'string') as roomNo, temp, UUID() as messageID
insert into RoomTempStream;

This will converts a room number to string, introducing a message ID to each event asUUID() returns a34eec40-32c2-44fe-8075-7f4fde2e2dd8

from TempStream
select convert(roomNo, 'string') as roomNo, temp, UUID() as messageID
insert into RoomTempStream;

cast (Function)¶

Converts the first parameter according to the cast.to parameter. Incompatible arguments cause Class Cast exceptions if further processed. This function is used with map extension that returns attributes of the object type. You can use this function to cast the object to an accurate and concrete type.

Syntax

<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> cast(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> to.be.caster, <STRING> cast.to)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
to.be.caster	This specifies the attribute to be casted.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No
cast.to	A string constant parameter expressing the cast to type using one of the following strings values: int, long, float, double, string, bool.		STRING	No	No

Examples EXAMPLE 1

from fooStream
select symbol as name, cast(temp, 'double') as temp
insert into barStream;

This will cast the fooStream temp field value into 'double' format.

coalesce (Function)¶

Returns the value of the first input parameter that is not null, and all input parameters have to be on the same type.

Syntax

<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> coalesce(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> args)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
args	This function accepts one or more parameters. They can belong to any one of the available types. All the specified parameters should be of the same type.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select coalesce('123', null, '789') as value
insert into barStream;

This will returns first null value 123.

EXAMPLE 2

from fooStream
select coalesce(null, 76, 567) as value
insert into barStream;

This will returns first null value 76.

EXAMPLE 3

from fooStream
select coalesce(null, null, null) as value
insert into barStream;

This will returns null as there are no notnull values.

convert (Function)¶

Converts the first input parameter according to the convertedTo parameter.

Syntax

<INT|LONG|DOUBLE|FLOAT|STRING|BOOL> convert(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL> to.be.converted, <STRING> converted.to)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
to.be.converted	This specifies the value to be converted.		INT LONG DOUBLE FLOAT STRING BOOL	No	No
converted.to	A string constant parameter to which type the attribute need to be converted using one of the following strings values: 'int', 'long', 'float', 'double', 'string', 'bool'.		STRING	No	No

Examples EXAMPLE 1

from fooStream
select convert(temp, 'double') as temp
insert into barStream;

This will convert fooStream temp value into 'double'.

EXAMPLE 2

from fooStream
select convert(temp, 'int') as temp
insert into barStream;

This will convert fooStream temp value into 'int' (value = "convert(45.9, 'int') returns 46").

createSet (Function)¶

Includes the given input parameter in a java.util.HashSet and returns the set.

Syntax

<OBJECT> createSet(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL> input)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
input	The input that needs to be added into the set.		INT LONG DOUBLE FLOAT STRING BOOL	No	No

Examples EXAMPLE 1

from stockStream 
select createSet(symbol) as initialSet 
insert into initStream;

For every incoming stockStream event, the initStream stream will produce a set object having only one element: the symbol in the incoming stockStream.

currentTimeMillis (Function)¶

Returns the current timestamp of siddhi application in milliseconds.

Syntax

<LONG> currentTimeMillis()

Examples EXAMPLE 1

from fooStream
select symbol as name, currentTimeMillis() as eventTimestamp 
insert into barStream;

This will extract current siddhi application timestamp.

default (Function)¶

Checks if the 'attribute' parameter is null and if so returns the value of the 'default' parameter

Syntax

<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> default(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> attribute, <INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> default)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
attribute	The attribute that could be null.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No
default	The default value that will be used when 'attribute' parameter is null		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from TempStream
select default(temp, 0.0) as temp, roomNum
insert into StandardTempStream;

This will replace TempStream's temp attribute with default value if the temp is null.

eventTimestamp (Function)¶

Returns the timestamp of the processed event.

Syntax

<LONG> eventTimestamp()

Examples EXAMPLE 1

from fooStream
select symbol as name, eventTimestamp() as eventTimestamp 
insert into barStream;

This will extract current events timestamp.

ifThenElse (Function)¶

Evaluates the 'condition' parameter and returns value of the 'if.expression' parameter if the condition is true, or returns value of the 'else.expression' parameter if the condition is false. Here both 'if.expression' and 'else.expression' should be of the same type.

Syntax

<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> ifThenElse(<BOOL> condition, <INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> if.expression, <INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> else.expression)

QUERY PARAMETERS

Name	Description	Possible Data Types	Optional	Dynamic
condition	This specifies the if then else condition value.	BOOL	No	No
if.expression	This specifies the value to be returned if the value of the condition parameter is true.	INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No
else.expression	This specifies the value to be returned if the value of the condition parameter is false.	INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

@info(name = 'query1')
from sensorEventStream
select sensorValue, ifThenElse(sensorValue>35,'High','Low') as status
insert into outputStream;

This will returns High if sensorValue = 50.

EXAMPLE 2

@info(name = 'query1')
from sensorEventStream
select sensorValue, ifThenElse(voltage < 5, 0, 1) as status
insert into outputStream;

This will returns 1 if voltage= 12.

EXAMPLE 3

@info(name = 'query1')
from userEventStream
select userName, ifThenElse(password == 'admin', true, false) as passwordState
insert into outputStream;

This will returns passwordState as true if password = admin.

instanceOfBoolean (Function)¶

Checks whether the parameter is an instance of Boolean or not.

Syntax

<BOOL> instanceOfBoolean(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfBoolean(switchState) as state
insert into barStream;

This will return true if the value of switchState is true.

EXAMPLE 2

from fooStream
select instanceOfBoolean(value) as state
insert into barStream;

if the value = 32 then this will returns false as the value is not an instance of the boolean.

instanceOfDouble (Function)¶

Checks whether the parameter is an instance of Double or not.

Syntax

<BOOL> instanceOfDouble(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfDouble(value) as state
insert into barStream;

This will return true if the value field format is double ex : 56.45.

EXAMPLE 2

from fooStream
select instanceOfDouble(switchState) as state
insert into barStream;

if the switchState = true then this will returns false as the value is not an instance of the double.

instanceOfFloat (Function)¶

Checks whether the parameter is an instance of Float or not.

Syntax

<BOOL> instanceOfFloat(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfFloat(value) as state
insert into barStream;

This will return true if the value field format is float ex : 56.45f.

EXAMPLE 2

from fooStream
select instanceOfFloat(switchState) as state
insert into barStream;

if the switchState = true then this will returns false as the value is an instance of the boolean not a float.

instanceOfInteger (Function)¶

Checks whether the parameter is an instance of Integer or not.

Syntax

<BOOL> instanceOfInteger(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfInteger(value) as state
insert into barStream;

This will return true if the value field format is integer.

EXAMPLE 2

from fooStream
select instanceOfInteger(switchState) as state
insert into barStream;

if the switchState = true then this will returns false as the value is an instance of the boolean not a long.

instanceOfLong (Function)¶

Checks whether the parameter is an instance of Long or not.

Syntax

<BOOL> instanceOfLong(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfLong(value) as state
insert into barStream;

This will return true if the value field format is long ex : 56456l.

EXAMPLE 2

from fooStream
select instanceOfLong(switchState) as state
insert into barStream;

if the switchState = true then this will returns false as the value is an instance of the boolean not a long.

instanceOfString (Function)¶

Checks whether the parameter is an instance of String or not.

Syntax

<BOOL> instanceOfString(<INT|LONG|DOUBLE|FLOAT|STRING|BOOL|OBJECT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	The parameter to be checked.		INT LONG DOUBLE FLOAT STRING BOOL OBJECT	No	No

Examples EXAMPLE 1

from fooStream
select instanceOfString(value) as state
insert into barStream;

This will return true if the value field format is string ex : 'test'.

EXAMPLE 2

from fooStream
select instanceOfString(switchState) as state
insert into barStream;

if the switchState = true then this will returns false as the value is an instance of the boolean not a string.

maximum (Function)¶

Returns the maximum value of the input parameters.

Syntax

<INT|LONG|DOUBLE|FLOAT> maximum(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	This function accepts one or more parameters. They can belong to any one of the available types. All the specified parameters should be of the same type.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

@info(name = 'query1') from inputStream
select maximum(price1, price2, price3) as max
insert into outputStream;

This will returns the maximum value of the input parameters price1, price2, price3.

minimum (Function)¶

Returns the minimum value of the input parameters.

Syntax

<INT|LONG|DOUBLE|FLOAT> minimum(<INT|LONG|DOUBLE|FLOAT> arg)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
arg	This function accepts one or more parameters. They can belong to any one of the available types. All the specified parameters should be of the same type.		INT LONG DOUBLE FLOAT	No	No

Examples EXAMPLE 1

@info(name = 'query1') from inputStream
select maximum(price1, price2, price3) as max
insert into outputStream;

This will returns the minimum value of the input parameters price1, price2, price3.

sizeOfSet (Function)¶

Returns the size of an object of type java.util.Set.

Syntax

<INT> sizeOfSet(<OBJECT> set)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
set	The set object. This parameter should be of type java.util.Set. A set object may be created by the 'set' attribute aggregator in Siddhi.		OBJECT	No	No

Examples EXAMPLE 1

from stockStream 
select initSet(symbol) as initialSet 
insert into initStream; 

;from initStream#window.timeBatch(10 sec) 
select union(initialSet) as distinctSymbols 
insert into distinctStockStream; 

from distinctStockStream 
select sizeOfSet(distinctSymbols) sizeOfSymbolSet 
insert into sizeStream;

The sizeStream stream will output the number of distinct stock symbols received during a sliding window of 10 seconds.

pol2Cart (Stream Function)¶

The pol2Cart function calculating the cartesian coordinates x & y for the given theta, rho coordinates and adding them as new attributes to the existing events.

Syntax

pol2Cart(<DOUBLE> theta, <DOUBLE> rho, <DOUBLE> z)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
theta	The theta value of the coordinates.		DOUBLE	No	No
rho	The rho value of the coordinates.		DOUBLE	No	No
z	z value of the cartesian coordinates.	If z value is not given, drop the third parameter of the output.	DOUBLE	Yes	No

Examples EXAMPLE 1

from PolarStream#pol2Cart(theta, rho)
select x, y 
insert into outputStream ;

This will return cartesian coordinates (4.99953024681082, 0.06853693328228748) for theta: 0.7854 and rho: 5.

EXAMPLE 2

from PolarStream#pol2Cart(theta, rho, 3.4)
select x, y, z 
insert into outputStream ;

This will return cartesian coordinates (4.99953024681082, 0.06853693328228748, 3.4)for theta: 0.7854 and rho: 5 and z: 3.4.

log (Stream Processor)¶

The logger logs the message on the given priority with or without processed event.

Syntax

log(<STRING> priority, <STRING> log.message, <BOOL> is.event.logged)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
priority	The priority/type of this log message (INFO, DEBUG, WARN, FATAL, ERROR, OFF, TRACE).	INFO	STRING	Yes	No
log.message	This message will be logged.		STRING	No	No
is.event.logged	To log the processed event.	true	BOOL	Yes	No

Examples EXAMPLE 1

from fooStream#log("INFO", "Sample Event :", true)
select *
insert into barStream;

This will log as INFO with the message "Sample Event :" + fooStream:events.

EXAMPLE 2

from fooStream#log("Sample Event :", true)
select *
insert into barStream;

This will logs with default log level as INFO.

EXAMPLE 3

from fooStream#log("Sample Event :", fasle)
select *
insert into barStream;

This will only log message.

EXAMPLE 4

from fooStream#log(true)
select *
insert into barStream;

This will only log fooStream:events.

EXAMPLE 5

from fooStream#log("Sample Event :")
select *
insert into barStream;

This will log message and fooStream:events.

batch (Window)¶

A window that holds an incoming events batch. When a new set of events arrives, the previously arrived old events will be expired. Batch window can be used to aggregate events that comes in batches.

Syntax

batch()

Examples EXAMPLE 1

define stream consumerItemStream (itemId string, price float)

from consumerItemStream#window.batch()
select price, str:groupConcat(itemId) as itemIds
group by price
insert into outputStream;

This will output comma separated items IDs that have the same price for each incoming batch of events.

cron (Window)¶

This window returns events processed periodically as the output in time-repeating patterns, triggered based on time passing.

Syntax

cron(<STRING> cron.expression)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
cron.expression	The cron expression that represents a time schedule.		STRING	No	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int)cron('*/5 * * * * ?');
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow 
select symbol,price,volume
insert into outputStream ;

This will processed events as the output every 5 seconds.

delay (Window)¶

A delay window holds events for a specific time period that is regarded as a delay period before processing them.

Syntax

delay(<INT|LONG|TIME> window.delay)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.delay	The time period (specified in sec, min, ms) for which the window should delay the events.		INT LONG TIME	No	No

Examples EXAMPLE 1

define window delayWindow(symbol string, volume int) delay(1 hour);
define stream PurchaseStream(symbol string, volume int);
define stream DeliveryStream(symbol string);
define stream OutputStream(symbol string);

@info(name='query1') 
from PurchaseStream
select symbol, volume
insert into delayWindow;

@info(name='query2') 
from delayWindow join DeliveryStream
on delayWindow.symbol == DeliveryStream.symbol
select delayWindow.symbol
insert into OutputStream;

In this example, purchase events that arrive in the 'PurchaseStream' stream are directed to a delay window. At any given time, this delay window holds purchase events that have arrived within the last hour. These purchase events in the window are matched by the 'symbol' attribute, with delivery events that arrive in the 'DeliveryStream' stream. This monitors whether the delivery of products is done with a minimum delay of one hour after the purchase.

externalTime (Window)¶

A sliding time window based on external time. It holds events that arrived during the last windowTime period from the external timestamp, and gets updated on every monotonically increasing timestamp.

Syntax

externalTime(<LONG> timestamp, <INT|LONG|TIME> window.time)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
timestamp	The time which the window determines as current time and will act upon. The value of this parameter should be monotonically increasing.		LONG	No	No
window.time	The sliding time period for which the window should hold events.		INT LONG TIME	No	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) externalTime(eventTime, 20 sec) output expired events;

@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;

@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert expired events into outputStream ;

processing events arrived within the last 20 seconds from the eventTime and output expired events.

externalTimeBatch (Window)¶

A batch (tumbling) time window based on external time, that holds events arrived during windowTime periods, and gets updated for every windowTime.

Syntax

externalTimeBatch(<LONG> timestamp, <INT|LONG|TIME> window.time, <INT|LONG|TIME> start.time, <INT|LONG|TIME> timeout)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
timestamp	The time which the window determines as current time and will act upon. The value of this parameter should be monotonically increasing.		LONG	No	No
window.time	The batch time period for which the window should hold events.		INT LONG TIME	No	No
start.time	User defined start time. This could either be a constant (of type int, long or time) or an attribute of the corresponding stream (of type long). If an attribute is provided, initial value of attribute would be considered as startTime.	Timestamp of first event	INT LONG TIME	Yes	No
timeout	Time to wait for arrival of new event, before flushing and giving output for events belonging to a specific batch.	System waits till an event from next batch arrives to flush current batch	INT LONG TIME	Yes	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) externalTimeBatch(eventTime, 1 sec) output expired events;
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert expired events into outputStream ;

This will processing events that arrive every 1 seconds from the eventTime.

EXAMPLE 2

define window cseEventWindow (symbol string, price float, volume int) externalTimeBatch(eventTime, 20 sec, 0) output expired events;

This will processing events that arrive every 1 seconds from the eventTime. Starts on 0^th millisecond of an hour.

EXAMPLE 3

define window cseEventWindow (symbol string, price float, volume int) externalTimeBatch(eventTime, 2 sec, eventTimestamp, 100) output expired events;

This will processing events that arrive every 2 seconds from the eventTim. Considers the first event's eventTimestamp value as startTime. Waits 100 milliseconds for the arrival of a new event before flushing current batch.

frequent (Window)¶

This window returns the latest events with the most frequently occurred value for a given attribute(s). Frequency calculation for this window processor is based on Misra-Gries counting algorithm.

Syntax

frequent(<INT> event.count, <STRING> attribute)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
event.count	The number of most frequent events to be emitted to the stream.		INT	No	No
attribute	The attributes to group the events. If no attributes are given, the concatenation of all the attributes of the event is considered.	The concatenation of all the attributes of the event is considered.	STRING	Yes	No

Examples EXAMPLE 1

@info(name = 'query1')
from purchase[price >= 30]#window.frequent(2)
select cardNo, price
insert all events into PotentialFraud;

This will returns the 2 most frequent events.

EXAMPLE 2

@info(name = 'query1')
from purchase[price >= 30]#window.frequent(2, cardNo)
select cardNo, price
insert all events into PotentialFraud;

This will returns the 2 latest events with the most frequently appeared card numbers.

length (Window)¶

A sliding length window that holds the last windowLength events at a given time, and gets updated for each arrival and expiry.

Syntax

length(<INT> window.length)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.length	The number of events that should be included in a sliding length window.		INT	No	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) length(10) output all events;
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert all events into outputStream ;

This will processing 10 events and out put all events.

lengthBatch (Window)¶

A batch (tumbling) length window that holds a number of events specified as the windowLength. The window is updated each time a batch of events that equals the number specified as the windowLength arrives.

Syntax

lengthBatch(<INT> window.length)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.length	The number of events the window should tumble.		INT	No	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) lengthBatch(10) output all events;

@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;

@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert all events into outputStream ;

This will processing 10 events as a batch and out put all events.

lossyFrequent (Window)¶

This window identifies and returns all the events of which the current frequency exceeds the value specified for the supportThreshold parameter.

Syntax

lossyFrequent(<DOUBLE> support.threshold, <DOUBLE> error.bound, <STRING> attribute)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
support.threshold	The support threshold value.		DOUBLE	No	No
error.bound	The error bound value.		DOUBLE	No	No
attribute	The attributes to group the events. If no attributes are given, the concatenation of all the attributes of the event is considered.	The concatenation of all the attributes of the event is considered.	STRING	Yes	No

Examples EXAMPLE 1

define stream purchase (cardNo string, price float);
define window purchaseWindow (cardNo string, price float) lossyFrequent(0.1, 0.01);
@info(name = 'query0')
from purchase[price >= 30]
insert into purchaseWindow;
@info(name = 'query1')
from purchaseWindow
select cardNo, price
insert all events into PotentialFraud;

lossyFrequent(0.1, 0.01) returns all the events of which the current frequency exceeds 0.1, with an error bound of 0.01.

EXAMPLE 2

define stream purchase (cardNo string, price float);
define window purchaseWindow (cardNo string, price float) lossyFrequent(0.3, 0.05, cardNo);
@info(name = 'query0')
from purchase[price >= 30]
insert into purchaseWindow;
@info(name = 'query1')
from purchaseWindow
select cardNo, price
insert all events into PotentialFraud;

lossyFrequent(0.3, 0.05, cardNo) returns all the events of which the cardNo attributes frequency exceeds 0.3, with an error bound of 0.05.

session (Window)¶

This is a session window that holds events that belong to a specific session. The events that belong to a specific session are identified by a grouping attribute (i.e., a session key). A session gap period is specified to determine the time period after which the session is considered to be expired. A new event that arrives with a specific value for the session key is matched with the session window with the same session key.
When performing aggregations for a specific session, you can include events with the matching session key that arrive after the session is expired if required. This is done by specifying a latency time period that is less than the session gap period.
To have aggregate functions with session windows, the events need to be grouped by the session key via a 'group by' clause.

Syntax

session(<INT|LONG|TIME> window.session, <STRING> window.key, <INT|LONG|TIME> window.allowedlatency)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.session	The time period for which the session considered is valid. This is specified in seconds, minutes, or milliseconds (i.e., 'min', 'sec', or 'ms'.		INT LONG TIME	No	No
window.key	The grouping attribute for events.	default-key	STRING	Yes	No
window.allowedlatency	This specifies the time period for which the session window is valid after the expiration of the session. The time period specified here should be less than the session time gap (which is specified via the 'window.session' parameter).	0	INT LONG TIME	Yes	No

Examples EXAMPLE 1

define stream PurchaseEventStream (user string, item_number int, price float, quantity int);

@info(name='query0) 
from PurchaseEventStream#window.session(5 sec, user, 2 sec) 
select * 
insert all events into OutputStream;

This query processes events that arrive at the PurchaseEvent input stream. The 'user' attribute is the session key, and the session gap is 5 seconds. '2 sec' is specified as the allowed latency. Therefore, events with the matching user name that arrive 2 seconds after the expiration of the session are also considered when performing aggregations for the session identified by the given user name.

sort (Window)¶

This window holds a batch of events that equal the number specified as the windowLength and sorts them in the given order.

Syntax

sort(<INT> window.length, <STRING> attribute, <STRING> order)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.length	The size of the window length.		INT	No	No
attribute	The attribute that should be checked for the order.	The concatenation of all the attributes of the event is considered.	STRING	Yes	No
order	The order define as "asc" or "desc".	asc	STRING	Yes	No

Examples EXAMPLE 1

define stream cseEventStream (symbol string, price float, volume long);
define window cseEventWindow (symbol string, price float, volume long) sort(2,volume, 'asc');
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow
select volume
insert all events into outputStream ;

sort(5, price, 'asc') keeps the events sorted by price in the ascending order. Therefore, at any given time, the window contains the 5 lowest prices.

time (Window)¶

A sliding time window that holds events that arrived during the last windowTime period at a given time, and gets updated for each event arrival and expiry.

Syntax

time(<INT|LONG|TIME> window.time)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.time	The sliding time period for which the window should hold events.		INT LONG TIME	No	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) time(20) output all events;
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert all events into outputStream ;

This will processing events that arrived within the last 20 milliseconds.

timeBatch (Window)¶

A batch (tumbling) time window that holds events that arrive during window.time periods, and gets updated for each window.time.

Syntax

timeBatch(<INT|LONG|TIME> window.time, <INT> start.time)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.time	The batch time period for which the window should hold events.		INT LONG TIME	No	No
start.time	This specifies an offset in milliseconds in order to start the window at a time different to the standard time.	Timestamp of first event	INT	Yes	No

Examples EXAMPLE 1

define window cseEventWindow (symbol string, price float, volume int) timeBatch(20 sec) output all events;

@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;

@info(name = 'query1')
from cseEventWindow
select symbol, sum(price) as price
insert all events into outputStream ;

This will processing events arrived every 20 seconds as a batch and out put all events.

timeLength (Window)¶

A sliding time window that, at a given time holds the last window.length events that arrived during last window.time period, and gets updated for every event arrival and expiry.

Syntax

timeLength(<INT|LONG|TIME> window.time, <INT> window.length)

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
window.time	The sliding time period for which the window should hold events.		INT LONG TIME	No	No
window.length	The number of events that should be be included in a sliding length window..		INT	No	No

Examples EXAMPLE 1

define stream cseEventStream (symbol string, price float, volume int);
define window cseEventWindow (symbol string, price float, volume int) timeLength(2 sec, 10);
@info(name = 'query0')
from cseEventStream
insert into cseEventWindow;
@info(name = 'query1')
from cseEventWindow select symbol, price, volume
insert all events into outputStream;

window.timeLength(2 sec, 10) holds the last 10 events that arrived during last 2 seconds and gets updated for every event arrival and expiry.

Sink¶

inMemory (Sink)¶

In-memory transport that can communicate with other in-memory transports within the same JVM, itis assumed that the publisher and subscriber of a topic uses same event schema (stream definition).

Syntax

@sink(type="inMemory", topic="<STRING>", @map(...)))

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
topic	Event will be delivered to allthe subscribers of the same topic		STRING	No	No

Examples EXAMPLE 1

@sink(type='inMemory', @map(type='passThrough'))
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses inMemory transport which emit the Siddhi events internally without using external transport and transformation.

log (Sink)¶

This is a sink that can be used as a logger. This will log the output events in the output stream with user specified priority and a prefix

Syntax

@sink(type="log", priority="<STRING>", prefix="<STRING>", @map(...)))

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
priority	This will set the logger priority i.e log level. Accepted values are INFO, DEBUG, WARN, FATAL, ERROR, OFF, TRACE	INFO	STRING	Yes	No
prefix	This will be the prefix to the output message. If the output stream has event [2,4] and the prefix is given as "Hello" then the log will show "Hello : [2,4]"	default prefix will be :	STRING	Yes	No

Examples EXAMPLE 1

@sink(type='log', prefix='My Log', priority='DEBUG'),
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses log sink and the prefix is given as My Log. Also the priority is set to DEBUG.

EXAMPLE 2

@sink(type='log', priority='DEBUG'),
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses log sink and the priority is set to DEBUG. User has not specified prefix so the default prefix will be in the form <Siddhi App Name> : <Stream Name>

EXAMPLE 3

@sink(type='log', prefix='My Log'),
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses log sink and the prefix is given as My Log. User has not given a priority so it will be set to default INFO.

EXAMPLE 4

@sink(type='log'),
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses log sink. The user has not given prefix or priority so they will be set to their default values.

Sinkmapper¶

passThrough (Sink Mapper)¶

Pass-through mapper passed events (Event[]) through without any mapping or modifications.

Syntax

@sink(..., @map(type="passThrough")

Examples EXAMPLE 1

@sink(type='inMemory', @map(type='passThrough'))
define stream BarStream (symbol string, price float, volume long);

In the following example BarStream uses passThrough outputmapper which emit Siddhi event directly without any transformation into sink.

Source¶

inMemory (Source)¶

In-memory source that can communicate with other in-memory sinks within the same JVM, it is assumed that the publisher and subscriber of a topic uses same event schema (stream definition).

Syntax

@source(type="inMemory", topic="<STRING>", @map(...)))

QUERY PARAMETERS

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
topic	Subscribes to sent on the given topic.		STRING	No	No

Examples EXAMPLE 1

@source(type='inMemory', @map(type='passThrough'))
define stream BarStream (symbol string, price float, volume long)

In this example BarStream uses inMemory transport which passes the received event internally without using external transport.

Sourcemapper¶

passThrough (Source Mapper)¶

Pass-through mapper passed events (Event[]) through without any mapping or modifications.

Syntax

@source(..., @map(type="passThrough")

Examples EXAMPLE 1

@source(type='tcp', @map(type='passThrough'))
define stream BarStream (symbol string, price float, volume long);

In this example BarStream uses passThrough inputmapper which passes the received Siddhi event directly without any transformation into source.

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