Siddhi Extensions

Siddhi language has a wide verity of extension ranging from string processing to natural language processing. These extensions can be utilized in numerous scenarios to manipulate attributes with ease. When using extensions within Siddhi queries you need to follow the convention of extensionName:functionName to refer to a particular extension. If the extension is of the Function type you can refer to it as shown in the following example in different parts of the query.

FROM inputStream[str:contains(description, "Pi-Value")]SELECT id, math:round(math:pi()) as roundedPiValue
INSERT INTO outputStream;

If the extension is of the Stream Processor type, you can refer to it as follows.
#reorder:kslack(eventTimestamp)

e.g.,

@info(name = 'query1')FROM inputStream#reorder:kslack(eventTimestamp)
SELECT eventTimestamp, price, volume
INSERT INTO outputStream;

The extensions that are currently available for Siddhi are as follows.

math

Math extension provides basic mathematical functions such as calculating absolute value, sin, cos, tan, base conversion, parsing, etc. Following are the functions of the Math extension.

abs

Syntax	`<double> abs(<float\|double> p1)`
Extension Type	Function
Description	Returns the absolute value of `p1` . This function wraps the `java.lang.Math.abs()` function.
Examples	Both the following queries return 3 since the absolute value of both `3` and `-3` is `3`. `abs(3)` `abs(-3)`

acos

Syntax	`<double> acos(<float\|double> p1)`
Extension Type	Function
Description	If -1 <= p1 <= 1, this function returns the arc-cosine (inverse cosine) of `p1`. If not, it returns `NULL.` The return value is in radian scale. This function wraps the `java.lang.Math.acos()` function.
Example	`acos(0.5)` returns `1.0471975511965979`.

asin

Syntax	`<double> asin (<float\|double> p1)`
Extension Type	Function
Description	If -1 <= p1 <= 1, this function returns the arc-sin (inverse sine) of `p1` . If not, it returns `NULL`. The return value is in radian scale. This function wraps the `java.lang.Math.asin()` function.
Example	`asin(0.5)` returns `0.5235987755982989`.

atan

Syntax	`<double> atan(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the arc-tangent (inverse tangent) of `p1`. The return value is in radian scale. This function wraps the `java.lang.Math.atan()` function.
Examples	`atan(6d)` returns `1.4056476493802699`.

Syntax	`<double> atan (<int\|long\|float\|double> p1, <int\|long\|float\|double> p2)`
Extension Type	Function
Description	Returns the arc-tangent (inverse tangent) of `p1` and `p2` coordinates. The return value is in radian scale. This function wraps the `java.lang.Math.atan2()` function.
Examples	`atan(12d, 5d)` returns `1.1760052070951352`.

bin

Syntax	`<string> bin(<int\|long> p1)`
Extension Type	Function
Description	Returns a string representation of the integer/long p1 argument as an unsigned integer in base `2`. This function wraps the `java.lang.Integer.toBinaryString` and `java.lang.Long.toBinaryString` methods.
Examples	`bin(9)` returns `"1001"`.

ceil

Syntax	`<double> ceil(<float\|double> p1)`
Extension Type	Function
Description	Returns the smallest (closest to negative infinity) double value that is greater than or equal to the p1 argument, and is equal to a mathematical integer. This function wraps the `java.lang.Math.ceil()` method.
Example	`ceil(423.187d)` returns `424.0`.

conv

Syntax	`<string> conv(<string> a, <int> fromBase, <int> toBase)`
Extension Type	Function
Description	Converts `a` from the `fromBase` base to the `toBase` base.
Example	`conv("7f", 16, 10)` returns `"127"`.

copySign

Syntax	`<double> copySign(<int\|long\|float\|double> magnitude, <int\|long\|float\|double> sign)`
Extension Type	Function
Description	Returns the magnitude of `magnitude` with the sign of `sign` . This function wraps the `java.lang.Math.copySign()` function.
Example	`copySign(5.6d, -3.0d)` returns `-5.6`.

cos

Syntax	`<double> cos(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the cosine of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.cos()` function.
Example	`cos(6d)` returns `0.9601702866503661`.

cosh

Syntax	`<double> cosh(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the hyperbolic cosine of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.cosh()` function.
Example	`cosh (6d)` returns `201.7156361224559`.

cbrt

Syntax	`<double> cbrt(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the cube-root of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.cbrt()` function.
Example	`cbrt(17d)` returns `2.5712815906582356`.

e

Syntax	`<double> e()`
Extension Type	Function
Description	Returns the `java.lang.Math.E` constant, which is the closest double value to `e` (which is the base of the natural logarithms).
Example	`e()` returns `2.7182818284590452354`.

exp

Syntax	`<double> exp(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns Euler's number `e` raised to the power of `p1` . This function wraps the `java.lang.Math.exp()` function.
Example	`exp(10.23)` returns `27722.51006805505`.

floor

Syntax	`<double> floor(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	This function wraps the `java.lang.Math.floor()` function that returns the largest (closest to positive infinity) value that is less that or equal to `p1` , and is equal to a mathematical integer.
Example	`floor(10.23)` returns `10.0.`

getExponent

Syntax	`<double> getExponent(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the unbiased exponent used in the representation of `p1` . This function wraps the `java.lang.Math.getExponent()` function.
Example	`getExponent(60984.1)` returns `15`.

hex

Syntax	`<string> hex(<int\|long\|float\|double> p1)`
Extension Type	Function
Description	This function wraps the `java.lang.Double.toHexString()` function that returns a hexadecimal string representation of `p1` .
Example	`hex(200)` returns `"c8"`.

isInfinite

Syntax	`<boolean> isInfinite(<float\|double> p1)`
Extension Type	Function
Description	This function wraps the `java.lang.Float.isInfinite()` and `java.lang.Double.isInfinite()` functions that return `true` if `p1` is infinitely large in magnitude, or return `false` otherwise.
Example	`isInfinite(java.lang.Double.POSITIVE_INFINITY)` returns `true`.

isNan

Syntax	`< boolean> isNan(<float\|double> p1)`
Extension Type	Function
Description	This function wraps the `java.lang.Float.isNaN()` and `java.lang.Double.isNaN()` functions that return `true` if `p1` is a `NaN` (Not-a-Number) value, or return false otherwise.
Example	`isNan(java.lang.Math.log(-12d)`) returns `true`.

ln

Syntax	`<double> ln (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the natural logarithm (base e) of `p1` .
Example	`ln(11.453)` returns `2.438251704415579`.

log2

Syntax	`<double> log2 (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the `base 2` logarithm of `p1` .
Example	`log2(91d)` returns `6.507794640198696`.

log10

Syntax	`<double> log10 ( < int\|long\|float\|double > p1 )`
Extension Type	Function
Description	Returns the base 10 logarithm of p1.
Example	`log10(19.234)` returns `1.2840696117100832`.

log

Syntax	`<double> log (< int\|long\|float\|double > number, < int\|long\|float\|double > base )`
Extension Type	Function
Description	Returns the logarithm (base=base) of `number` .
Example	`log(34, 2f)` returns `5.08746284125034`.

max

Syntax	`<double> max (< int\|long\|float\|double > p1, <int\|long\|float\|double> p2 )`
Extension Type	Function
Description	Returns the greater value out of `p1` and `p2` .
Example	`max(123.67d, 91)` returns `123.67`.

min

Syntax	`<double> min (< int\|long\|float\|double > p1, <int\|long\|float\|double> p2 )`
Extension Type	Function
Description	Returns the smaller value out of `p1` and `p2` .
Example	`min(123.67d, 91)` returns `91`.

oct

Syntax	`<string> oct (<int\|long> p1)`
Extension Type	Function
Description	Converts `p1` to octal.
Example	`oct(99l)` returns `"143"`.

parseDouble

Syntax	`<double> parseDouble (<string> str)`
Extension Type	Function
Description	Returns `str` as a double.
Example	`parseDouble("123")` returns `123.0`.

parseFloat

Syntax	`<float> parseFloat (<string> str)`
Extension Type	Function
Description	Returns `str` as a float.
Example	`parseFloat("123")` returns `123.0`.

parseInt

Syntax	`<int> parseInt (<string> str)`
Extension Type	Function
Description	Returns `str` as an int.
Example	`parseInt("123")` returns `123`.

parseLong

Syntax	`<long> parseLong (<string> str)`
Extension Type	Function
Description	Returns `str` as a long.
Example	`parseLong("123")` returns `123`.

pi

Syntax	`<double> pi ( )`
Extension Type	Function
Description	Returns the `java.lang.Math.PI` constant, which is the closest value to `pi` (i.e. the ratio of the circumference of a circle to its diameter).
Example	`pi()` always returns `3.141592653589793`.

power

Syntax	`<double> power ( < int\|long\|float\|double> value, <int\|long\|float\|double> toPower )`
Extension Type	Function
Description	Returns `value` raised to the power of `toPower`.
Example	`power(5.6d, 3.0d)` returns `175.61599999999996`.

rand

Syntax	`<double> rand ( )`
Extension Type	Function
Description	A sequence of calls to `rand()` generates a stream of pseudo-random numbers. This function uses the `java.util.Random` class internally.
Example	Two sequential calls to `rand()` may return `0.8263929447650588` and `0.24425883860361197` respectively.

Syntax	`<double> rand (< int\|long > seed)`
Extension Type	Function
Description	A sequence of calls to `rand(seed`) generates a stream of pseudo-random numbers. This function uses the `java.util.Random` class internally.
Example	Two sequential calls to `rand(12)` may return `0.7298928061101974` and `0.2750691655200749`, respectively.

round

Syntax	`<int> round (<float> value )`
Extension Type	Funcion
Description	Returns the closest integer value to the argument.
Example	`round(3.35)` returns `3`.

Syntax	`<long> round (<double> value )`
Extension Type	Function
Description	Returns the closest long value to the argument.
Example	`round(3252.353)` returns `3252`.

signum

Syntax	`<int> signum (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	If `a` is a positive, this returns the sign of `p1` as `1.0`. If `a` is a negative, this returns the sign of `p1` as -`1.0`. If `a` is neither a positive or a negative, this returns the sign of `p1` as `0.0`. This function wraps the `java.lang.Math.signum()` function.
Example	`signum(-6.32d)` returns `-1`.

sin

Syntax	`<double> sin (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the sine of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.sin()` function.
Example	`sin(6d`) returns `-0.27941549819892586.`

sinh

Syntax	`<double> sinh (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the hyperbolic sine of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.sinh()` function.
Example	`sinh(6d)` returns `201.71315737027922`.

sqrt

Syntax	`<double> sqrt (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the square-root of `p1` . This function wraps the `java.lang.Math.sqrt()` function.
Example	`sqrt(4d)` returns `2`.

tan

Syntax	`<double> tan (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Returns the tan of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.tan()` function.
Example	`tan(6d)` returns `-0.29100619138474915`.

tanh

Syntax	`<double> tanh (<int\|long\|float\|double> p1)`
Extension Type	Function
Description	Returns the hyperbolic tangent of `p1` ( `p1` is in radians). This function wraps the `java.lang.Math.tanh()` function.
Example	`tanh(6d)` returns `0.9999877116507956`.

toDegrees

Syntax	`<double> toDegrees (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Converts `p1` from radians to degrees. This function wraps the `java.lang.Math.toDegrees()` function.
Example	`toDegrees(6d)` returns `343.77467707849394`.

toRadians

Syntax	`<double> toRadians (< int\|long\|float\|double > p1)`
Extension Type	Function
Description	Converts `p1` from degrees to radians. This function wraps the `java.lang.Math.toRadians()` function.
Example	`toRadians(6d)` returns `0.10471975511965977`.

str

This extension provides basic string handling capabilities such as con-cat, length, convert to lowercase, replace all, etc. Following are the functions of the String extension.

charAt

Syntax	`<string> charAt(<string> str, <int> index)`
Extension Type	Function
Description	Returns the char value as a string value at the specified index.
Example	`charAt("WSO2", 1)` returns `'S'`.

coalesce

Syntax	`< int\|long\|float\|double\|string\|boolean > coalesce (< int\|long\|float\|double\|string\|boolean > arg1, < int\|long\|float\|double\|string\|boolean > arg2 ,.., < int\|long\|float\|double\|string\|boolean > argN )`
Extension Type	Function
Description	Returns the value of the first of its input parameters that is not null.
Parameters	This functions accepts any number of parameters. The parameters can be of different types.
Return Type	This is the same as the type of the first input parameter that is not null.
Examples	`coalesce("123", null, "789")` returns `"123"`. `coalesce(null, "BBB", "CCC")` returns `"BBB"`. `coalesce(null, null, null)` returns `null`.

concat

Syntax	`<string> concat ( <int\|long\|float\|double\|string\|boolean > arg1, < int\|long\|float\|double\|string\|boolean > arg2 ,.., < int\|long\|float\|double\|string\|boolean > argN )`
Extension Type	Function
Description	Returns a string that is the result of concatenating the given arguments: `arg1` , `arg2` , .., `argN` .
Examples	`concat("D533", "8JU^", "XYZ")` returns `"D5338JU^XYZ"`. `concat("AAA", null, "CCC")` returns `"AAACCC"`.

hex

Syntax	`<string> hex ( < string> str)`
Extension Type	Function
Description	Returns a hexadecimal string representation of `str` .
Example	`hex("MySQL")` returns `"4d7953514c"`.

length

Syntax	`<int> length ( < string> str)`
Extension Type	Function
Description	Returns the length of the string: `str` .
Examples	`length("Hello World")` returns `11`.

lower

Syntax	`<string> lower ( < string> str)`
Extension Type	Function
Description	Converts the capital letters in the `str` input string to the equivalent simple letters.
Example	`lower("WSO2 cep ")` returns `"wso2 cep "`.

regexp

Syntax	`<boolean> regexp ( < string> str, <string> regex )`
Extension Type	Function
Description	Returns `true` if the given string (i.e. `str` `)` matches the given regular expression (i.e. `regex` ). Returns `false` if the string does not match the regular expression.
Example	`regexp("WSO2 abcdh", "WSO(.*h)")` returns `true`.

repeat

Syntax	`<string> repeat ( < string> str, <int> times)`
Extension Type	Function
Description	Repeats the specified string (i.e. `string` ) for the specified number of times (i.e. `times` ).
Example	`repeat("StRing 1", 3)` returns `"StRing 1StRing 1StRing 1"`.

replaceAll

Syntax	`<string> replaceAll ( < string> str, <string> regex , <string> replacement)`
Extension Type	Function
Description	Replaces each substring of the given string (i.e. `str` ) that matches the given regular expression (i.e. `regex` ) with the string specified as the replacement (i.e. `replacement` ).
Example	`replaceAll("hello hi hello", 'hello', 'test')` returns `"test hi test"`.

replaceFirst

Syntax	`<string> replaceFirst (< string> str , <string> regex , <string> replacement )`
Extension Type	Function
Description	Replaces the first substring that matches the given regular expression (i.e. `regex`) with the string specified as the replacement (i.e. `replacement`)
Example	`replaceFirst("hello WSO2 A hello", 'WSO2(.*)A', 'XXXX')` returns `"hello XXXX hello"`.

reverse

Syntax	`<string> reverse ( < string> str)`
Extension Type	Function
Description	Returns the reverse ordered string of `str` .
Example	`reverse("Hello World")` returns `"dlroW olleH"`.

strcmp

Syntax	`<int> strcmp ( < string> str, <string> compareTo)`
Extension Type	Function
Description	Compares `str` with `compareTo` strings lexicographically.
Examples	`strcmp("Hello", 'Hello')` returns `0`. `strcmp("AbCDefghiJ KLMN", 'Hello')` returns `-7`.

substr

Syntax	`<string> substr ( < string> sourceText, <int> beginIndex )`
Extension Type	Function
Description	Returns a ne string that is a substring of `sourceText.`
Example	`substr("AbCDefghiJ KLMN", 4)` returns `"efghiJ KLMN"`.

Syntax	`<string> substr ( < string> sourceText, <int> beginIndex, <int> length )`
Extension Type	Function
Description	Returns a new string that is a substring of `sourceText`.
Example	`substr("AbCDefghiJ KLMN", 2, 4)` returns `"CDef"`.

Syntax	`<string> substr ( < string> sourceText, <string> regex)`
Extension Type	Function
Description	Returns a new string that is a substring of `sourceText`.
Examples	`substr("WSO2D efghiJ KLMN", '^WSO2(.*)')` returns `"WSO2D efghiJ KLMN"`.

Syntax	`<string> substr ( < string> sourceText, <string> regex, <int> groupNumber )`
Extension Type	Function
Description	Returns a new string that is a substring of `sourceText`.
Example	`substr("WSO2 cep WSO2 XX E hi hA WSO2 heAllo", 'WSO2(.)A(.)', 2)` returns `" ello"`.

trim

Syntax	`<string> trim ( < string> str)`
Extension Type	Function
Description	Returns a copy of `str` , with the leading and/or trailing white-spaces omitted.
Example	`trim(" AbCDefghiJ KLMN ")` returns `"AbCDefghiJ KLMN"`.

unhex

Syntax	`<string> unhex ( < string> str)`
Extension Type	Function
Description	This is the equivalent of the `unhex` function in mysql 5.0. `unhex(str)` interprets each pair of characters in `str` as a hexadecimal number. Also see hex () string extension.
Example	`unhex("4d7953514c")` returns `"MySQL"`.

upper

Syntax	`<string> upper ( <string> str)`
Extension Type	Function
Description	Converts the simple letters in the given input string (i.e. `str` ) to the equivalent capital letters.
Example	`upper("Hello World")` returns `"HELLO WORLD"`.

contains

Syntax	`<bool> contains ( < string> inputSequence, <string> searchingSequence )`
Extension Type	Function
Description	This method returns `true` if `inputSequence` contains the specified sequence of char values in the `searchingSequence` .
Example	`contains("21 products are produced by WSO2 currently", "WSO2")` returns `true`.

geo

This extension provides geo data related functionality such as checking whether a given geo coordinate is within a predefined geo-fence, etc. Following are the functions of the Geo extension.

intersects

Syntax	`<bool> intersects (<string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the `geoJSONGeometry` incoming event intersects the given string (i.e. `geoJSONGeometryFence`). Returns `false` otherwise.
Example	`intersects( {'type':'Polygon','coordinates':[[[0.5, 0.5],[0.5, 1.5],[1.5, 1.5],[1.5, 0.5],[0.5, 0.5]]]} , {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]} ),` returns `true` because `geoJSONGeometry` intersects `geoJSONGeometryFence`.

Syntax	`<bool> intersects (<double> longitude , <double> latitude , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude intersects the given `geoJSONGeometryFence` . Returns `false` otherwise.
Example	`intersects(0.5. 0.5 , {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}),` returns `true` because the location specified in terms of longitude and latitude intersects `geoJSONGeometryFence`.

within

Syntax	`<bool> within (<double> longitude , <double> latitude, <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude is within the `geoJSONGeometryFence`.
Examples	`within(0.5, 0.5, {'type':'Polygon','coordinates':[[[0,0],[0,2],[1,2],[1,0],[0,0]]]} )` returns `true`. `within(2, 2, {'type':'Polygon','coordinates':[[[0,0],[0,2],[1,2],[1,0],[0,0]]]} )` returns `false`.

Syntax	`<bool> within (<string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns true if the `geoJSONGeometry` is within the `geoJSONGeometryFence`. Returns `false` otherwise.
Example	`within( {'type': 'Circle', 'radius': 110575, 'coordinates':[1.5, 1.5]} , {'type':'Polygon','coordinates':[[[0,0],[0,4],[3,4],[3,0],[0,0]]]} )` returns `true`. `within( {'type': 'Circle', 'radius': 110575, 'coordinates':[0.5, 1.5]} , {'type':'Polygon','coordinates':[[[0,0],[0,4],[3,4],[3,0],[0,0]]]} )` returns `false`.

withindistance

Syntax	`<bool> withindistance (<double> longitude , <double> latitude, <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` if the location specified in terms of longitude and latitude is within distance of the `geoJSONGeometryFence`. Returns `false` otherwise.
Example	`withindistance( 0.5 , 0.5, {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}, 110574.61087757687)` returns `true` because the location specified in terms of longitude and latitude is within the distance of the `geoJSONGeometryFence`.

Syntax	`<bool> withindistance (<string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> distance )`
Extension Type	Function
Description	Returns `true` if the area given by `geoJSONGeometry` is within distance of the `geoJSONGeometryFence`.
Example	`withindistance( {'type':'Polygon','coordinates':[[[0.5, 0.5],[0.5, 1.5],[1.5, 1.5],[1.5, 0.5],[0.5, 0.5]]]} , {'type':'Polygon','coordinates':[[[0, 0],[0, 1],[1, 1],[1, 0],[0, 0]]]}, 110574.61087757687)` returns `true` because `geoJSONGeometry` is within the distance of `geoJSONGeometryFence`.

crosses

Syntax	`<bool> crosses (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence )`
Extension Type	Function
Description	Returns `true` when the the specified object of which the location is specified in terms of `longitude` and `latitude` crosses the geographic location specified in `geoJSONGeometryFence` . Returns `false` when the object crosses out of the location specified in `geoJSONGeometryFence` .
Example	`crosses(km-4354, -0.5, 0.5, {'type':'Polygon','coordinates':[[[0, 0],[2, 0],[2, 1],[0, 1],[0, 0]]]} )` returns `true`. `km-4354, 1.5, 0.5, {'type':'Polygon','coordinates':[[[0, 0],[2, 0],[2, 1],[0, 1],[0, 0]]]} )` returns `true`.

Syntax	`<bool> crosses (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence )`
Extension Type	StreamProcessor
Description	Returns true when the object (i.e. `geoJSONGeometry` ) crosses the specified geographic location (i.e. `geoJSONGeometryFence` ). Returns `false` when the object crosses out of `geoJSONGeometryFence` .

stationary

Syntax	`<bool> stationary (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when the object (defined in terms of `longitude` and `latitude` ) becomes stationary within the specified `radius` . Returns `false` when the object moves out of the specified radius.
Example	`stationary(km-4354,0,0, 110574.61087757687)` returns `true`. `stationary(km-4354,1,1, 110574.61087757687)` returns `true .` `stationary(km-4354,1,1.5, 110574.61087757687)` returns `true`.

Syntax	`<bool> stationary (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when the object (i.e. `geoJSONGeometry` ) becomes stationary within the specified `radius` `.` Returns `false` when the objects moves out of the specified radius.

proximity

Syntax	`<bool,string> proximity (<string> id , <double> longitude, <double> latitude , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when two objects (specified in terms of `longitude` and `latitude)`are within the specified `radius` to another object. Returns `false` when the specified object moves out of the specified `radius` . The `proximityWith` optional attribute indicates the ID of the object that the object specified is in close proximity with. `proximityID` is a unique ID for the two objects in close proximity.
Example	The following return `true` with `ID3`. `proximity(1, 0, 0, 110574.61087757687)` `proximity(2, 1, 1, 110574.61087757687)` `proximity(3, 2, 2, 110574.61087757687)` `proximity(1, 1.5, 1.5, 110574.61087757687)`

Syntax	`<bool> proximity (<string> id , <string> geoJSONGeometry , <string> geoJSONGeometryFence , <double> radius )`
Extension Type	StreamProcessor
Description	Returns `true` when an object (i.e. `geoJSONGeometry` ) is within the specified `radius` from another object. Returns `false` when one or both objects move away from each other and are no longer within the specified `radiu`s of each other. The `proximityWith` optional attribute indicates the ID of the object that the object specified is in close proximity with. `proximityID` is a unique ID for the two objects in close proximity.

geocode

Syntax	`<double, double, string> geocode (<string> location` `)`
Extension Type	StreamProcessor
Description	Transforms a location to its geo-coordinates ( `longitude` and `latitude` ) and formatted address.
Example	`geocode(duplication rd)` returns the following data with adherring latitude, longitude, and `formattedAddress` attribute names respectively. `6.8995244d, 79.8556202d, "R A De Mel Mawatha, Colombo, Sri Lanka"`

r

This extension allows you to execute R scripts within Siddhi query. Following are the functions of the R extension.

eval

Syntax	`[<int\|long\|float\|double\|string\|boolean> output1 , <int\|long\|float\|double\|string\|boolean> output2, ... ] eval ( <string > script, <string > outputAttributes, <int\|long\|float\|double\|string\|boolean > input1 , <int\|long\|float\|double\|string\|boolean> input2 , ... )`
Extension Type	StreamProcessor
Description	This runs the R script for each event and produces aggregated outputs based on the provided input variable parameters and expected output attributes.
Parameters	`script` : R script as a string produces aggregated outputs based on the provided input variable parameters and expected output attributes. `outputAttributes` : A set of output attributes separated by commas as string. Each attribute is denoted as `<name><space><type>`. e.g., `'output1 string, output2 long'`
Return Parameters	Output parameters are generated based on the `outputAttributes` provided.
Example	`eval('totalItems <- sum(items); totalTemp <- sum(temp);', 'totalItems int, totalTemp double', items, temp)`, where the data type of `items` is `int` and that of `temp` is `double` returns `[ totalItems, totalTemp ]`, where the data type of `totalItems` is `int` and that of `totalTemp` is `double`.

evalSource

Syntax	`[<int\|long\|float\|double\|string\|boolean> output1 , <int\|long\|float\|double\|string\|boolean> output2, ... ] eval ( <string > filePath, <string > outputAttributes,<int\|long\|float\|double\|string\|boolean> input1 , <int\|long\|float\|double\|string\|boolean> input2 , ... )`
Extension Type	Stream Processor
Description	This runs the R script loaded from a file to each event and produces aggregated outputs based on the provided input variable parameters and expected output attributes.
Parameters	`filePath` : The file path of the R script where this script uses the input variable parameters and produces the expected output attributes. `outputAttributes` : A set of output attributes separated by commas as string. Each attribute is denoted as `<name><space><type>` . e.g., `'output1 string, output2 long'`
Return	Output parameters are generated based on the `outputAttributes` provided.
Example	`eval('/home/user/test/script1.R', 'totalItems int, totalTemp double', items, temp)`, where the data type of `items` is `int` and that of `temp` is `double` returns `[ totalItems, totalTemp ]` where the data type of `totalTemp` is `int` and that of `totalTemp` is double.

regex

This extension provides basic RegEx execution capabilities to Siddhi. Following are the functions of the RegEx extension.

find

Syntax	`<bool> find (<string> regex , <string> inputSequence )`
Extension Type	Function
Description	This method attempts to find the next sub-sequence of the `inputSequence` that matches the `regex` pattern. It returns `true` if such a sub sequence exists, or returns `false` otherwise.
Examples	`find("\d\d(.)WSO2", "21 products are produced by WSO2 currently")` returns `true`. `find("\d\d(.)WSO2", "21 products are produced currently")` returns `false`.

Syntax	`<bool> find (<string> regex , <string> inputSequence, <int> startingIndex )`
Extension Type	Function
Description	This method attempts to find the next sub-sequence of the `inputSequence` that matches the `regex` pattern starting from given index (i.e. `startingIndex` ). It returns `true` if such a sub sequence exists, or returns `false` otherwise.
Examples	`find("\d\d(.)WSO2", "21 products are produced within 10 years by WSO2 currently by WSO2 employees", 30)` returns `true`. `find("\d\d(.)WSO2", "21 products are produced within 10 years by WSO2 currently by WSO2 employees", 35)` returns `false`.

group

Syntax	`<string> group (<string> regex , <string> inputSequence , <int> groupId )`
Extension Type	Function
Description	Returns the input sub-sequence captured by the given group during the previous match operation. Returns `null` if no sub-sequence was found during the previous match operation. For more information about the match operation, see matches.
Example	`group("(\d\d)(.)(WSO2.)", "21 products are produced within 10 years by WSO2 currently by WSO2 employees", 3)` returns `"WSO2 employees"`.

lookingAt

Syntax	`<string> lookingAt (<string> regex , <string> inputSequence )`
Extension Type	Function
Description	This method attempts to match the `inputSequence` against the `regex` pattern starting at the beginning.
Examples	`lookingAt("\d\d(.)WSO2", "21 products are produced by WSO2 currently in Sri Lanka"`) returns `true`. `lookingAt("WSO2(.)middleware(.*)", "sample test string and WSO2 is situated in trace and its a middleware company")` returns `false`.

matches

Syntax	`<string> matches (<string> regex , <string> inputSequence )`
Extension Type	Function
Description	This method attempts to match the entire `inputSequence` against the `regex` pattern.
Examples	`matches("WSO2(.)middleware(.)", "WSO2 is situated in trace and its a middleware company")` returns `true`. `matches("WSO2(.*)middleware", "WSO2 is situated in trace and its a middleware company")` returns `false`.

time

This extension provides time related functionality to Siddhi such as getting current time, current date, manipulating/formatting dates, etc. Following are the functions of the time extension.

currentDate

Syntax	`<string> currentDate ( )`
Extension Type	Function
Description	Returns the current system date in the `yyyy-MM-dd` format.
Example	`currentDate()` returns `2015-08-20`.

currentTime

Syntax	`<string> currentTime ( )`
Extension Type	Function
Description	Returns the current system time in the `HH:mm:ss` format.
Example	`currentTime()` returns `13:15:10`.

currentTimestamp

Syntax	`<string> currentTimestamp ( )`
Extension Type	Function
Description	Returns the current system timestamp in the `yyyy-MM-dd HH:mm:ss` format.
Example	`currentTime()` returns `2015-08-20 13:15:10`.

dateAdd

The common parameters of this function are described below.

Syntax	`<string> dateAdd (<string> dateValue , <long> expr, <string> unit, <string> dateFormat )`
Extension Type	Function
Description	Returns the specified date and time with the selected `unit`of the specified `dateValue` incremented by the given amount (i.e. `expr` ).
Example	`dateAdd("2014-11-11 13:23:44", 2, 'year',"yyyy-MM-dd HH:mm:ss")` returns `"2016-11-11 13:23:44"`.

Syntax	`<string> dateAdd (<string> dateValue , < long > expr, <string> unit )`
Extension Type	Function
Description	Returns the specified date and time with the selected `unit` of the specified `dateValue` incremented by the given amount (i.e. `expr` ).
Example	`dateAdd("2014-11-11 13:23:44", 2, 'year')` returns `"2016-11-11 13:23:44"`.

Syntax	`<string> dateAdd (<long> timestampInMilliseconds, < long > expr, <string> unit )`
Extension Type	Function
Description	Returns the specified time stamp with the selected `unit` of the specified `timestampInMilliseconds` incremented by the given amount (i.e. `expr` ).
Example	`dateAdd(1415692424000L, 2, 'year')` returns `"2016-11-11 13:23:44"`.

dateSub

The common parameters of this function are described below.

Syntax	`<string> dateSub (<string> dateValue , <long> expr, <string> unit, <string> dateFormat )`
Extension Type	Function
Description	Returns the specified date and time with the selected `unit` of the specified `dateValue` reduced by the given amount (i.e. `expr` ).
Example	`dateSub("2014-11-11 13:23:44", 2, 'year',"yyyy-MM-dd HH:mm:ss")` returns `"2012-11-11 13:23:44"`.

Syntax	`<string> dateSub (<string> dateValue , < long > expr, <string> unit )`
Extension Type	Function
Description	Returns the specified date and time stamp with he selected `unit` of the specified `dateValue` reduced by the given amount (i.e. `expr` ).
Example	`dateSub("2014-11-11 13:23:44", 2, 'year')` returns `"2012-11-11 13:23:44".`

Syntax	`<string> dateSub (<long> timestampInMilliseconds, < long > expr, <string> unit )`
Extension Type	Function
Description	Returns the specified time stamp with the selected `unit` of the specified `timestampInMilliseconds` reduced by the given amount (i.e. `expr` ).
Example	`dateSub(1415692424000L, 2, 'year')` returns `1352620424000.`

dateDiff

The common parameters of this function are described below.

Syntax	`<int> dateDiff (<string> dateValue1 , < string > dateValue2 , <string> dateFormat1, <string> dateFormat2 )`
Extension Type	Function
Description	Returns the number of days between the two dates specified (i.e. `dateValue1` and `dateValue2` ).
Example	`dateDiff('2014-11-11 13:23:44', '2014-11-9 13:23:44', 'yyyy-MM-dd HH:mm:ss', 'yyyy-MM-dd HH:mm:ss')` returns `2`.

Syntax	`<int> dateDiff (<string> dateValue1 , < string > dateValue2 )`
Extension Type	Function
Description	Returns the number of days between the two dates specified (i.e. `dateValue1` and `dateValue2` ).
Example	`dateDiff('2014-11-11 13:23:44.000', '2014-11-9 13:23:44.000'`) returns `2`.

Syntax	`<int> dateDiff (<string> timestampInMilliseconds1 , < string > timestampInMilliseconds2 )`
Extension Type	Function
Description	Returns the number of days between the two date and time stamps specified (i.e. `timestampInMilliseconds1` and `timestampInMilliseconds2` ).
Example	`dateDiff(1415692424000, 1415519624000)` returns `2`.

dateFormat

The common parameters of this function are described below.

Syntax	`<string> dateFormat(<string> dateValue,<string> dateTargetFormat,<string> dateSourceFormat)`
Extension Type	Function
Description	Returns a formatted date string.
Example	`dateFormat('2014-11-11 13:23:55', 'ss', 'yyyy-MM-dd HH:mm:ss')` returns `55`.

Syntax	`<string> dateFormat(<string> dateValue,<string> dateTargetFormat)`
Extension Type	Function
Description	Returns a formatted date string.
Example	`dateFormat('2014-11-11 13:23:55.657', 'ss')` returns `55`.

Syntax	`<string> dateFormat (<long> timestampInMilliseconds ,<string> dateTargetFormat)`
Extension Type	Function
Description	Returns a formatted date string.
Example	`dateFormat(1415692424000, 'yyyy-MM-dd')` returns `2014-11-11.`

extract

Syntax	`<int> extract (<string> unit ,<string> dateValue, <string> dataFormat)`
Extension Type	Function
Description	Returns the specified `unit` extracted from the specified `dateValue` .
Example	`extract('year', '2014-3-11 02:23:44', 'yyyy-MM-dd hh:mm:ss')` returns `2014`.

Syntax	`<int> extract (<string> unit ,<string> dateValue)`
Extension Type	Function
Description	Returns the specified `unit` extracted from the specified `dateValue` .
Example	`extract('year', '2014-3-11 02:23:44.234')` returns `2014`.

Syntax	`<int> extract (<long> timestampInMilliseconds ,<string> unit)`
Extension Type	Function
Description	Returns the specified `unit` extracted from the specified `timestampInMilliseconds` .
Example	`extract(1394484824000, 'year')` returns `2014`.

date

Syntax	`<string> date (<string> dateValue ,<string> dateFormat)`
Extension Type	Function
Description	Returns the date component of the `dateValue`.
Example	`extact('2014-11-11 13:23:44', 'yyyy-MM-dd HH:mm:ss')` returns `2014-11-11`.

timestampInMilliseconds

Syntax	`<long> timestampInMilliseconds ()`
Extension Type	Function
Description	Returns the current time stamp in milliseconds.
Example	`timestampInMilliseconds()` returns `1440160328693`.

Syntax	`<long> timestampInMilliseconds (<string> dateValue)`
Extension Type	Function
Description	Returns the time stamp of the specified `dateValue` in milliseconds. In order to use this function, the date format of the specified `dateValue` should be `yyyy-MM-dd HH:mm:ss.SSS`.
Example	`timestampInMilliseconds('2007-11-30 10:30:19.000')` returns `1196398819000`.

Syntax	`<long> timestampInMilliseconds (<string> dateValue, <string> dateFormat)`
Extension Type	Function
Description	Returns the time stamp of the specified `dateValue` in milliseconds. The date format can be specified in the `dateForma` t parameter.
Example	`timestampInMilliseconds('2007-11-30 10:30:19', 'yyyy-MM-dd HH:mm:ss')` returns `1196398819000`.

utcTimestamp

Syntax	`<string> utcTimestamp()`
Extension Type	Function
Description	Returns the system time in the `yyyy-MM-dd HH:mm:ss` date format.
Example	`utcTimestamp()` returns `2015-08-21 12:16:13`.

nlp

This extension provides Natural Language Processing capabilities to Siddhi. Functions of the NLP extension are as follows.

findNameEntityType

Syntax	`<string> findNameEntityType(<string> entityType, <bool> groupSuccessiveMatch, <string> string-variable )`
Extension Type	Function
Description	This function uses the following input parameters. `entityType`: This is a user-specified string constant. e.g., `PERSON`, `LOCATION`, `ORGANIZATION`, `MONEY`, `PERCENT`, `DATE` or `TIME` `groupSuccessiveMatch` : This is a user-specified boolean constant used to group successive matches of the specified `entityType` and a text stream. `streamAttribute`: A string or the stream attribute in which text stream is included. This function returns the entities in the text. If you specify group successive matches as `true`, the result aggregates successive words of the same entity type.
Example	`findNameEntityType("PERSON",true,text)` In the above example, if the text attribute contains "`Bill Gates donates £31million to fight Ebola"`, the result is `Bill Gates`. If the group successive match is set to `false`, two events are generated as `Bill` and `Gates`.

findNameEntityTypeViaDictionary

Syntax	`<string> findNameEntityTypeViaDictionary(<string> entityType, <string> dictionaryFilePath, <string> string-variable )`
Extension Type	Function
Description	This function uses the following input parameters. `entityType`: This is a user-specified string constant. e.g., `PERSON`, `LOCATION`, `ORGANIZATION`, `MONEY`, `PERCENT`, `DATE` or `TIME` `dictionaryFilePath`: The path to the dictionary in which the function searches for the specified entries. The relevant entries for the entity types should be available in the dictionary as shown in the example below. `streamAttribute`: A string or the stream attribute in which text stream is included. This function returns the entities in the text. If you specify group successive matches as `true` , the result aggregates successive words of the same entity type.
Example	`findNameEntityTypeViaDictionary("PERSON","dictionary.xml",text)` In the above example, if the text attribute contains `"Bill Gates donates £31million to fight Ebola"`, and the dictionary consists of the above entries (i.e. entries of the example in the Description), the result is `"Bill"`.

findRelationshipByVerb

Syntax	`<string > text, <string> subject, < string > object < string > verb findRelationshipByVerb (<string> verb, <string> string-variable )`
Extension Type	Function
Description	`findRelationshipByVerb` takes in a user specified string constant as a verb and a text stream, and returns the whole text, subject, object and the verb based on the specified verb. This information can be extracted only if the verb specified exists in the text stream. However, the tense of the verb does not have to match. The input parameters used are as follows. `verb` : This is a user specified string constant. `string-variable` : A string or the stream attribute which includes the text stream.
Examples	`findRelationshipByVerb("say", "Information just reaching us says another Liberian With Ebola Arrested At Lagos Airport")` returns the following. The whole text `Information` as the subject `Liberian` as the object. `says` as the verb.

findRelationshipByRegex

Syntax	`<string > text, <string> subject, < string > object < string > verb findRelationshipByRegex (<string> regex, <string> string-variable )`
Extension Type	Function
Description	This function returns the whole text, subject, object and verb from the text stream that matches the named nodes of the Semgrex pattern.
Example	`findRelationshpByRegex('{}=verb >/nsubj\|agent/ {}=subject >/dobj/ {}=object', "gates foundation donates $50M in support of #Ebola relief")` returns the following. The whole text `"foundation"` as the subject `"$"` as the object `"donates"` as the verb

findSemgrexPattern

Syntax	`<string > text, <string> match, < string > object < string > verb findSemgrexPattern (<string> regex, <string> string-variable )`
Extension Type	Function
Description	The `findSemgrexPattern` function returns the whole text, subject, object and verb from the text stream that matches the named nodes of the Semgrex pattern. This function uses the following input parameters. `regex` : A user specified regular expression that matches the Semgrex pattern syntax. `string-variable` : A string or the stream attribute which includes the text stream.
Example	`findSemgrexPattern('{lemma:die} >/.subj\|num./=reln {}=diedsubject', "Sierra Leone doctor dies of Ebola after failed evacuation.")` In this example, the function searches for words with the lemmatization `die` that are governors on any subject or numeric relation. The dependent is marked as the `diedsubject`, and the relationship is marked as `reln`. Thus, the query returns an output stream that has the full match of this expression, i.e. the governing word with lemmatization for `die`. It also returns the name of the corresponding node for each match it finds. The following is the list of elements in the output stream. The whole text `dies` as the match `"nsubj"` as `reln` `doctor` asdiedsubject

findTokensRegexPattern

Syntax	`< string > text, <string> match, <string> group_1, etc. findTokensRegexPattern (<string> regex, <string> string-variable )`
Extension Type	Function
Description	`findTokensRegexPattern` returns the whole text, subject, object and verb from the text stream that matches the named nodes of the Semgrex pattern. The return also includes the corresponding node in the Semgrex pattern and the corresponding named relation defined in the regular expression for each word/phrase. This function uses the following input parameters. `regex` : A user specified regular expression that matches the Semgrex pattern syntax. `string-variable` : A string or the stream attribute which includes the text stream.
Example	`findTokensRegexPattern('([ner:/PERSON\|ORGANIZATION\|LOCATION/]+) (?:[]* [lemma:donate]) ([ner:MONEY]+)', text)` defines three groups: The first group looks for words that are entities of either `PERSON`, `ORGANIZATON` or `LOCATION` with one or more successive words matching same. The middle group is defined as the non capturing group. Third looks for one or more successive entities of type `MONEY`. This function returns the following. `The whole text` `" Paul Allen donates $ 9million "` as the match. `" Paul Allen"`, as group_1. `"$ 9million"` as group_2.

pmml

This extension adds PMML based predictive analytic model compliance to Siddhi. It allows you to make predictions based on a predictive analytic model. Supported functions of PMML extension are as follows.

predict

Syntax	`< double \| float\|long\|int\|string\|boolean > predict(<string> pathToPmmlFile)`
Extension Type	Stream Processor
Description	Processes the input stream attributes according to the defined PMML standard model and outputs the processed results together with the input stream attributes. This function uses the following input parameter. `pathToPmmlFile` : The path to the PMML model file. The function returns the outputs defined in the output fields. The number of outputs can vary.
Example	`predict('<DAS HOME>/samples/artifacts/0301/decision-tree.pmml')` This model is implemented to detect network intruders. The input event stream is processed by the execution plan that uses the pmml predictive model to detect whether a particular user is an intruder to the network or not. The output stream contains the processed query results that include the predicted responses together with the feature values extracted from the input event stream.

Syntax	`< double \| float\|long\|int\|string\|boolean > predict(<string> pathToPmmlFile, <double\|float\|long\|int\|string\|boolean> input )`
Extension Type	Stream Processor
Description	Processes the input stream attributes according to the defined PMML standards model and outputs the processed results. This function uses the following input parameters. `pathToPmmlFile` : The path to the PMML model file. `input` : An attribute of the input stream that is sent to the PMML standard model as a value to based on which the prediction is made. The `predict` function does not accept any constant values as input parameters. You can have multiple input parameters according to the input stream definition. This function returns the processed outputs defined in the query. The number of outputs can vary depending on the query definition.
Examples	`predict('<DAS_HOME>/samples/artifacts/0301/ decision-tree.pmml', root_shell, su_attempted, num_root, num_file_creations, num_shells, num_access_files, num_outbound_cmds, is_host_login, is_guest_login, count, srv_count, serror_rate, srv_serror_rate )` This model is implemented to detect network intruders. The input event stream is processed by the execution plan that uses the pmml predictive model to detect whether a particular user is an intruder to the network or not. The output stream contains the processed query results that include the predicted responses.

ml

This extension provides Siddhi the capability to make predictions based on Machine Learning models. Supported functions of the ML extension are as follows.

predict

Syntax	`<double\|float\|long\|int\|string\|boolean> predict(<string> pathToMLModel, <string> dataType)`
Extension Type	Stream Processor
Description	Returns an output event with the additional attribute that has the response variable name of the model, set with the predicted value, using the feature values extracted from the input event. This function uses the following input parameters. `pathToMLModel` : The file path or the registry path to the location of the ML model. If the model storage location is registry, the value of this parameter should have `registry` as the prefix. `dataType` : The data type of the predicted value (`double`, `float`, `long`, `integer/int`, `string`, `boolean`/`bool`).
Example	`predict(‘registry:/_system/governance/mlmodels/indian-diabetes-model’)`

Syntax	`<double\|float\|long\|int\|string\|boolean> predict(<string> pathToMLModel, <string> dataType, <double> input)`
Extension Type	Stream Processor
Description	Returns an output event with the additional attribute that has the response variable name of the model, set with the predicted value, using the feature values extracted from the input event. This function uses the following input parameters. `pathToMLModel` : The file path or the registry path to the location of the ML model. If the model storage location is registry, the value of this parameter should have `registry` as the prefix. `dataType` : The data type of the predicted value (`double`, `float`, `long`, `integer/int`, `string`, `boolean`/`bool`). `input` : An attribute of the input stream that is sent to the ML model as a value to based on which the prediction is made. The `predict` function does not accept any constant values as input parameters. You can have multiple input parameters.
Example	`predict(‘registry:/_system/governance/mlmodels/indian-diabetes-model’, NumPregnancies, TSFT, DPF, BMI, DBP, PG2, Age, SI2)`

timeseries

See Time Series Extension.

kf (Kalman Filter)

This extension provides Kalman filtering capabilities to Siddhi. This allows you to detect outliers of input data. Following are the functions of the Kalman Filter extension.

Kalman Filter function

This function uses measurements observed over time containing noise and other inaccuracies, and produces estimated values for the current measurement using Kalman algorithms.

The parameters used in this function are as follows.

measuredValue : The sequential change in the observed measurement. e.g., 40.695881
measuredChangingRate: The rate at which the measured change is taking place. e.g., The velocity with which the measured value is changed can be 0.003 meters per second.
measurementNoiseSD: The standard deviation of the noise. e.g., 0.01
timestamp : The time stamp of the time at which the measurement was carried out.

Syntax	`<double, double> kf:kalmanFilter(<double> measuredValue)`
Extension Type	Function
Example	1st round: `kf:kalmanFilter(-74.178444)` returns an estimated value of `-74.178444`. 2nd round: `kf:kalmanFilter(-74.175703)` returns an estimated value of `-74.1770735006853`. 3rd round: `kf:kalmanFilter(-74.177872)` returns an estimated value of `-74.1773396670348`.

Syntax	`<double, double> kf: kalmanFilter(<double> measuredValue, <double> measurementNoiseSD)`
Extension Type	Function
Example	1st round: `kf:kalmanFilter(-74.178444, 0.003)` returns an estimated value of `-74.178444`. 2nd round: `kf:kalmanFilter(-74.175703, 0.003)` returns an estimated value of `-74.17707350205573`. 3rd round: `kf:kalmanFilter(-74.177872, 0.003)` returns an estimated value of `-74.177339667771`.

Syntax	`<double, double> kf: kalmanFilter(<double> measuredValue, <double> measuredChangingRate, <double> measurementNoiseSD, <long> timestamp)`
Extension Type	Function
Example	1st round: `kf:kalmanFilter(-74.178444, 0.003, 0.01, time:timestampInMilliseconds() )` returns an estimated value of `-74.1784439700006`. 2nd round: `kf:kalmanFilter(-74.178444, 0.003, 0.01, time:timestampInMilliseconds() )` returns an estimated value of `-74.1784439700006`. 3rd round: `kf:kalmanFilter(-74.177872, 0.003, 0.01, time:timestampInMilliseconds())` returns an estimated value of `-74.17697314316393`.

map

This extension provides the capability to send a map object inside Siddhi stream definitions and use it inside queries. The following are the functions of the map extension.

create

Syntax	`<Object> create()` or `<Object> create(<Object> key1, <Object> value1,<Object> key2, <Object> value2,...<Object> keyN, <Object> valueN)`
Extension Type	Function
Description	Returns the created map object.
Examples	`create()` returns an empty map. `create(1 , ”one” , 2 , ”two” , 3 , ”three”)` returns a map with keys `1, 2, 3` and corresponding values `"one", "two", "three"`.

get

Syntax	`<Object> get(<Map> map, <Object> key)`
Extension Type	Function
Description	Returns the value object from the map that is related to the given key.
Example	`get(company,1)` returns the value that is related to the key `1` from the map named `company`.

isMap

Syntax	`<bool> isMap(<Object> object)`
Extension Type	Function
Description	Returns `true` if the object is a map or `false` otherwise.
Example	`isMap(students)` returns `true` if the students object is a map. It returns `false` if the `students` object is not a map.

put

Syntax	`Object> put(<Object> map, <Object> key,<Object> value)`
Extension Type	Function
Description	Returns the updated map after adding the given key-value pair.
Example	`put(students , 1234 , ”sam”)` returns the updated map named `students` after adding the object `"sam"` with key `1234`.

remove

Syntax	`<Object> remove(<Object> map, <Object> key)`
Extension Type	Function
Description	Returns the updated map after removing the element with key.
Example	`remove(students , 1234)` returns the updated map `students` after removing the element with the key `1234`.

createFromJSON

Syntax	`<Object> createFromJSON(<string> JSONstring)`
Extension Type	Function
Description	Returns the map created with the key values pairs given in the `JSONstring`.
Example	`createFromJSON(“{‘symbol' : 'IBM' , 'price' : 200, 'volume' : 100}”)` returns a map with the keys "`symbol"`, `"price", "volume"`, and with the values `"IBM"`, `200` and `100` respectively.

createFromXML

Syntax	`<Object> createFromXML(<string> XMLstring)`
Extension Type	Function
Description	Returns the map created with the key values pairs given in the XMLstring.
Example	`createFromXML(“<company> <symbol> wso2 </symbol> <price> <100> </price> <volume> 200 </volume> </company>”)` returns a map with the keys `"symbol"`, `"price"`, `"volume"`, and with the values `WSO2`, `100` and `200` respectively.

toJSON

Syntax	`<string> toJSON(<Object> map)`
Extension Type	Function
Description	Converts a map into a JSON object and returns the definition of that JSON object as a string.
Example	If `"company"` is a map with key value pairs `("symbol" : wso2)`, `("volume" : 100)`, and `("price",200)`, `toJSON(company)` returns the string `“{“symbol” : “wso2” , “volume” : 100 , “price” : 200}”`.

toXML

Syntax	<string> toXML(<Object> map)
Extension Type	Function
Description	Returns the map as an XML string.
Example	If `"company"` is a map with key value pairs `(“symbol” : wso2)`, `(“volume” : 100)`, and `(“price” : 200)`, `toXML(map)` returns the string `“<symbol>wso2</symbol><volume><100></volume><price>200</price>`.

reorder

Reorder extension is implemented using the K-Slack algorithm. The K-Slack Siddhi extension is used for reordering events from an unordered event stream. The following is an example of a query with the reorder extension.

@info(name = 'query1') 
from inputStream#reorder:kslack(eventTimestamp) 
select eventTimestamp, price, volume 
insert into outputStream;

There are several important variations of the K-slack API of which the details are described below.

kslack

Syntax	`<bool> kslack(<long> timestamp)`
Extension Type	StreamProcessor
Description	This is the most basic version. The events are sorted by the `timestamp` parameter.

Syntax	`<bool> kslack(<long> timestamp, <long> timeOut )`
Extension Type	StreamProcessor
Description	The second argument shown in the above syntax corresponds to a fixed time-out value set at the beginning of the process. Once the time-out value expires, the extension drains all the events that are buffered within the reorder extension to outside. The time out has been implemented internally using a timer. The events buffered within the extension are released each time the timer ticks.

Syntax	<bool> kslack(<long> timestamp, <long> timeOut, <long> maxValue )
Extension Type	StreamProcessor
Description	The third argument in the above syntax is the maximum value for K. This is the amount to which the K value of the K-Slack algorithm will be increased.
Example	`kslack(timestamp, -1l, 1000000)` In the above example, the algorithm execution starts when K=0 and it gets increased up to 1000000. The value of the `K-slack` does not increase from that point onwards. Hence, this leads to lower latency compared to the version shown in the first (i.e., single parameter) example of this list. Note that the second argument is set to `-1l` which effectively disables the timer based draining of the internal buffer. `kslack(timestamp, 1000l, 1000000)` The above is another variation of the third category. Here, a time-out value is specified for the second argument (i.e. 1000 ms). In this case, the K-slack algorithm buffers events until the 1000ms time period expires. The maximum K value is 1000000. The K-value cannot exceed the specified amount.

Syntax	`<bool> kslack(<long> timestamp, <long> timeOut, <bool> expireFlag )`
Extension Type	StreamProcessor
Description	The fourth argument in the above syntax is a flag that indicates whether the out-of order events that appear after the expiration of the K-slack window should be discarded or not.
Example	`kslack(timestamp, -1l, -1l, true)`