com.couchbase.lite

Class Function

java.lang.Object

com.couchbase.lite.Function

public final class Function
extends Object

Query functions.

Constructor Summary

Constructors

Constructor and Description
Function()

Method Summary

Modifier and Type	Method and Description
static Expression	abs(Expression operand) Creates an ABS(expr) function that returns the absolute value of the given numeric expression.
static Expression	acos(Expression operand) Creates an ACOS(expr) function that returns the inverse cosine of the given numeric expression.
static Expression	asin(Expression operand) Creates an ASIN(expr) function that returns the inverse sin of the given numeric expression.
static Expression	atan(Expression operand) Creates an ATAN(expr) function that returns the inverse tangent of the numeric expression.
static Expression	atan2(Expression y, Expression x) Returns the angle theta from the conversion of rectangular coordinates (x, y) to polar coordinates (r, theta).
static Expression	avg(Expression operand) Creates an AVG(expr) function expression that returns the average of all the number values in the group of the values expressed by the given expression.
static Expression	ceil(Expression operand) Creates a CEIL(expr) function that returns the ceiling value of the given numeric expression.
static Expression	contains(Expression operand, Expression substring) Creates a CONTAINS(expr, substr) function that evaluates whether the given string expression conatins the given substring expression or not.
static Expression	cos(Expression operand) Creates a COS(expr) function that returns the cosine of the given numeric expression.
static Expression	cosineDistance(Expression expression1, Expression expression2) ENTERPRISE EDITION API
static Expression	count(Expression operand) Creates a COUNT(expr) function expression that returns the count of all values in the group of the values expressed by the given expression.
static Expression	degrees(Expression operand) Creates a DEGREES(expr) function that returns the degrees value of the given radiants value expression.
static Expression	e() Creates a E() function that return the value of the mathematical constant 'e'.
static Expression	euclideanDistance(Expression expression1, Expression expression2) ENTERPRISE EDITION API
static Expression	exp(Expression operand) Creates a EXP(expr) function that returns the value of 'e' power by the given numeric expression.
static Expression	floor(Expression operand) Creates a FLOOR(expr) function that returns the floor value of the given numeric expression.
static Expression	length(Expression operand) Creates a LENGTH(expr) function that returns the length of the given string expression.
static Expression	ln(Expression operand) Creates a LN(expr) function that returns the natural log of the given numeric expression.
static Expression	log(Expression operand) Creates a LOG(expr) function that returns the base 10 log of the given numeric expression.
static Expression	lower(Expression operand) Creates a LOWER(expr) function that returns the lowercase string of the given string expression.
static Expression	ltrim(Expression operand) Creates a LTRIM(expr) function that removes the whitespace from the beginning of the given string expression.
static Expression	max(Expression operand) Creates a MAX(expr) function expression that returns the maximum value in the group of the values expressed by the given expression.
static Expression	millisToString(Expression operand) Creates a MILLIS_TO_STR(expr) function that will convert a numeric input representing milliseconds since the Unix epoch into a full ISO8601 date and time string in the device local time zone.
static Expression	millisToUTC(Expression operand) Creates a MILLIS_TO_UTC(expr) function that will convert a numeric input representing milliseconds since the Unix epoch into a full ISO8601 date and time string in UTC time.
static Expression	min(Expression operand) Creates a MIN(expr) function expression that returns the minimum value in the group of the values expressed by the given expression.
static Expression	pi() Creates a PI() function that returns the mathematical constant Pi.
static Expression	power(Expression base, Expression exp) Creates a POWER(base, exponent) function that returns the value of the given base expression power the given exponent expression.
static PredictionFunction	prediction(String model, Expression input) ENTERPRISE EDITION API
static Expression	radians(Expression operand) Creates a RADIANS(expr) function that returns the radians value of the given degrees value expression.
static Expression	round(Expression operand) Creates a ROUND(expr) function that returns the rounded value of the given numeric expression.
static Expression	round(Expression operand, Expression digits) Creates a ROUND(expr, digits) function that returns the rounded value to the given number of digits of the given numeric expression.
static Expression	rtrim(Expression operand) Creates a RTRIM(expr) function that removes the whitespace from the end of the given string expression.
static Expression	sign(Expression operand) Creates a SIGN(expr) function that returns the sign (1: positive, -1: negative, 0: zero) of the given numeric expression.
static Expression	sin(Expression operand) Creates a SIN(expr) function that returns the sin of the given numeric expression.
static Expression	sqrt(Expression operand) Creates a SQRT(expr) function that returns the square root of the given numeric expression.
static Expression	squaredEuclideanDistance(Expression expression1, Expression expression2) ENTERPRISE EDITION API
static Expression	stringToMillis(Expression operand) Creates a STR_TO_MILLIS(expr) that will convert an ISO8601 datetime string into the number of milliseconds since the unix epoch.
static Expression	stringToUTC(Expression operand) Creates a STR_TO_UTC(expr) that will convert an ISO8601 datetime string into a full ISO8601 UTC datetime string.
static Expression	sum(Expression operand) Creates a SUM(expr) function expression that return the sum of all number values in the group of the values expressed by the given expression.
static Expression	tan(Expression operand) Creates a TAN(expr) function that returns the tangent of the given numeric expression.
static Expression	trim(Expression operand) Creates a TRIM(expr) function that removes the whitespace from the beginning and the end of the given string expression.
static Expression	trunc(Expression operand) Creates a TRUNC(expr) function that truncates all of the digits after the decimal place of the given numeric expression.
static Expression	trunc(Expression operand, Expression digits) Creates a TRUNC(expr, digits) function that truncates the number of the digits after the decimal place of the given numeric expression.
static Expression	upper(Expression operand) Creates a UPPER(expr) function that returns the uppercase string of the given string expression.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Function

public Function()

Method Detail

prediction

@NonNull
public static PredictionFunction prediction(@NonNull
                                                     String model,
                                                     @NonNull
                                                     Expression input)

ENTERPRISE EDITION API

Creates prediction function with the given model name and input. When running a query with the prediction function, the corresponding predictive model registered to CouchbaseLite Database class will be called with the given input to predict the result.

The prediction result returned by the predictive model will be in a form dictionary object. To create an expression that refers to a property in the prediction result, the propertyPath(path) method of the created PredictionFunction object can be used.

Parameters:

model - The predictive model name registered to the CouchbaseLite Database.

input - The expression evaluated to a dictionary.

Returns:

A PredictionFunction object.

euclideanDistance

@NonNull
public static Expression euclideanDistance(@NonNull
                                                    Expression expression1,
                                                    @NonNull
                                                    Expression expression2)

ENTERPRISE EDITION API

Creates a function that returns the euclidean distance between the two input vectors. The result is a non-negative floating-point number. The expression1 and expression2 must be arrays of numbers, and must be the same length.

Parameters:

expression1 - The expression evaluated to an arrays of numbers.

expression2 - The expression evaluated to an arrays of numbers.

Returns:

The euclidean distance between two given input vectors.

squaredEuclideanDistance

@NonNull
public static Expression squaredEuclideanDistance(@NonNull
                                                           Expression expression1,
                                                           @NonNull
                                                           Expression expression2)

ENTERPRISE EDITION API

Creates a function that returns the squared euclidean distance between the two input vectors. The result is a non-negative floating-point number. The expression1 and expression2 must be arrays of numbers, and must be the same length.

Parameters:

expression1 - The expression evaluated to an arrays of numbers.

expression2 - The expression evaluated to an arrays of numbers.

Returns:

The squared euclidean distance between two given input vectors.

cosineDistance

@NonNull
public static Expression cosineDistance(@NonNull
                                                 Expression expression1,
                                                 @NonNull
                                                 Expression expression2)

ENTERPRISE EDITION API

Creates a function that returns the cosine distance which one minus the cosine similarity between the two input vectors. The result is a floating-point number ranges from −1.0 to 1.0. The expression1 and expression2 must be arrays of numbers, and must be the same length.

Parameters:

expression1 - The expression evaluated to an arrays of numbers.

expression2 - The expression evaluated to an arrays of numbers.

Returns:

The cosine distance between two given input vectors.

avg

@NonNull
public static Expression avg(@NonNull
                                      Expression operand)

Creates an AVG(expr) function expression that returns the average of all the number values in the group of the values expressed by the given expression.

The expression.

Returns:

The AVG(expr) function.

count

@NonNull
public static Expression count(@Nullable
                                        Expression operand)

Creates a COUNT(expr) function expression that returns the count of all values in the group of the values expressed by the given expression. Null expression is count *

Parameters:

operand - The expression.

Returns:

The COUNT(expr) function.

min

@NonNull
public static Expression min(@NonNull
                                      Expression operand)

Creates a MIN(expr) function expression that returns the minimum value in the group of the values expressed by the given expression.

Parameters:

operand - The expression.

Returns:

The MIN(expr) function.

max

@NonNull
public static Expression max(@NonNull
                                      Expression operand)

Creates a MAX(expr) function expression that returns the maximum value in the group of the values expressed by the given expression.

Parameters:

operand - The expression.

Returns:

The MAX(expr) function.

sum

@NonNull
public static Expression sum(@NonNull
                                      Expression operand)

Creates a SUM(expr) function expression that return the sum of all number values in the group of the values expressed by the given expression.

Parameters:

operand - The expression.

Returns:

The SUM(expr) function.

abs

@NonNull
public static Expression abs(@NonNull
                                      Expression operand)

Creates an ABS(expr) function that returns the absolute value of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The ABS(expr) function.

acos

@NonNull
public static Expression acos(@NonNull
                                       Expression operand)

Creates an ACOS(expr) function that returns the inverse cosine of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The ACOS(expr) function.

asin

@NonNull
public static Expression asin(@NonNull
                                       Expression operand)

Creates an ASIN(expr) function that returns the inverse sin of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The ASIN(expr) function.

atan

@NonNull
public static Expression atan(@NonNull
                                       Expression operand)

Creates an ATAN(expr) function that returns the inverse tangent of the numeric expression.

Parameters:

operand - The expression.

Returns:

The ATAN(expr) function.

atan2

@NonNull
public static Expression atan2(@NonNull
                                        Expression y,
                                        @NonNull
                                        Expression x)

Returns the angle theta from the conversion of rectangular coordinates (x, y) to polar coordinates (r, theta).

Parameters:

x - the abscissa coordinate

y - the ordinate coordinate

Returns:

the theta component of the point (r, theta) in polar coordinates that corresponds to the point (x, y) in Cartesian coordinates.

ceil

@NonNull
public static Expression ceil(@NonNull
                                       Expression operand)

Creates a CEIL(expr) function that returns the ceiling value of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The CEIL(expr) function.

cos

@NonNull
public static Expression cos(@NonNull
                                      Expression operand)

Creates a COS(expr) function that returns the cosine of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The COS(expr) function.

degrees

@NonNull
public static Expression degrees(@NonNull
                                          Expression operand)

Creates a DEGREES(expr) function that returns the degrees value of the given radiants value expression.

Parameters:

operand - The expression.

Returns:

The DEGREES(expr) function.

e

@NonNull
public static Expression e()

Creates a E() function that return the value of the mathematical constant 'e'.

Returns:

The E() constant function.

exp

@NonNull
public static Expression exp(@NonNull
                                      Expression operand)

Creates a EXP(expr) function that returns the value of 'e' power by the given numeric expression.

Parameters:

operand - The expression.

Returns:

The EXP(expr) function.

floor

@NonNull
public static Expression floor(@NonNull
                                        Expression operand)

Creates a FLOOR(expr) function that returns the floor value of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The FLOOR(expr) function.

ln

@NonNull
public static Expression ln(@NonNull
                                     Expression operand)

Creates a LN(expr) function that returns the natural log of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The LN(expr) function.

log

@NonNull
public static Expression log(@NonNull
                                      Expression operand)

Creates a LOG(expr) function that returns the base 10 log of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The LOG(expr) function.

pi

@NonNull
public static Expression pi()

Creates a PI() function that returns the mathematical constant Pi.

Returns:

The PI() constant function.

power

@NonNull
public static Expression power(@NonNull
                                        Expression base,
                                        @NonNull
                                        Expression exp)

Creates a POWER(base, exponent) function that returns the value of the given base expression power the given exponent expression.

Parameters:

base - The base expression.

exp - The exponent expression.

Returns:

The POWER(base, exponent) function.

radians

@NonNull
public static Expression radians(@NonNull
                                          Expression operand)

Creates a RADIANS(expr) function that returns the radians value of the given degrees value expression.

Parameters:

operand - The expression.

Returns:

The RADIANS(expr) function.

round

@NonNull
public static Expression round(@NonNull
                                        Expression operand)

Creates a ROUND(expr) function that returns the rounded value of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The ROUND(expr) function.

round

@NonNull
public static Expression round(@NonNull
                                        Expression operand,
                                        @NonNull
                                        Expression digits)

Creates a ROUND(expr, digits) function that returns the rounded value to the given number of digits of the given numeric expression.

Parameters:

operand - The numeric expression.

digits - The number of digits.

Returns:

The ROUND(expr, digits) function.

sign

@NonNull
public static Expression sign(@NonNull
                                       Expression operand)

Creates a SIGN(expr) function that returns the sign (1: positive, -1: negative, 0: zero) of the given numeric expression.

Parameters:

operand - The expression.

Returns:

The SIGN(expr) function.

sin

@NonNull
public static Expression sin(@NonNull
                                      Expression operand)

Creates a SIN(expr) function that returns the sin of the given numeric expression.

Parameters:

operand - The numeric expression.

Returns:

The SIN(expr) function.

sqrt

@NonNull
public static Expression sqrt(@NonNull
                                       Expression operand)

Creates a SQRT(expr) function that returns the square root of the given numeric expression.

Parameters:

operand - The numeric expression.

Returns:

The SQRT(expr) function.

tan

@NonNull
public static Expression tan(@NonNull
                                      Expression operand)

Creates a TAN(expr) function that returns the tangent of the given numeric expression.

Parameters:

operand - The numeric expression.

Returns:

The TAN(expr) function.

trunc

@NonNull
public static Expression trunc(@NonNull
                                        Expression operand)

Creates a TRUNC(expr) function that truncates all of the digits after the decimal place of the given numeric expression.

Parameters:

operand - The numeric expression.

Returns:

The trunc function.

trunc

@NonNull
public static Expression trunc(@NonNull
                                        Expression operand,
                                        @NonNull
                                        Expression digits)

Creates a TRUNC(expr, digits) function that truncates the number of the digits after the decimal place of the given numeric expression.

Parameters:

operand - The numeric expression.

digits - The number of digits to truncate.

Returns:

The TRUNC(expr, digits) function.

contains

@NonNull
public static Expression contains(@NonNull
                                           Expression operand,
                                           @NonNull
                                           Expression substring)

Creates a CONTAINS(expr, substr) function that evaluates whether the given string expression conatins the given substring expression or not.

Parameters:

operand - The string expression.

substring - The substring expression.

Returns:

The CONTAINS(expr, substr) function.

length

@NonNull
public static Expression length(@NonNull
                                         Expression operand)

Creates a LENGTH(expr) function that returns the length of the given string expression.

Parameters:

operand - The string expression.

Returns:

The LENGTH(expr) function.

lower

@NonNull
public static Expression lower(@NonNull
                                        Expression operand)

Creates a LOWER(expr) function that returns the lowercase string of the given string expression.

Parameters:

operand - The string expression.

Returns:

The LOWER(expr) function.

ltrim

@NonNull
public static Expression ltrim(@NonNull
                                        Expression operand)

Creates a LTRIM(expr) function that removes the whitespace from the beginning of the given string expression.

Parameters:

operand - The string expression.

Returns:

The LTRIM(expr) function.

rtrim

@NonNull
public static Expression rtrim(@NonNull
                                        Expression operand)

Creates a RTRIM(expr) function that removes the whitespace from the end of the given string expression.

Parameters:

operand - The string expression.

Returns:

The RTRIM(expr) function.

trim

@NonNull
public static Expression trim(@NonNull
                                       Expression operand)

Creates a TRIM(expr) function that removes the whitespace from the beginning and the end of the given string expression.

Parameters:

operand - The string expression.

Returns:

The TRIM(expr) function.

upper

@NonNull
public static Expression upper(@NonNull
                                        Expression operand)

Creates a UPPER(expr) function that returns the uppercase string of the given string expression.

Parameters:

operand - The string expression.

Returns:

The UPPER(expr) function.

millisToString

@NonNull
public static Expression millisToString(@NonNull
                                                 Expression operand)

Creates a MILLIS_TO_STR(expr) function that will convert a numeric input representing milliseconds since the Unix epoch into a full ISO8601 date and time string in the device local time zone.

Parameters:

operand - The string expression.

Returns:

The MILLIS_TO_STR(expr) function.

millisToUTC

@NonNull
public static Expression millisToUTC(@NonNull
                                              Expression operand)

Creates a MILLIS_TO_UTC(expr) function that will convert a numeric input representing milliseconds since the Unix epoch into a full ISO8601 date and time string in UTC time.

Parameters:

operand - The string expression.

Returns:

The MILLIS_TO_UTC(expr) function.

stringToMillis

@NonNull
public static Expression stringToMillis(@NonNull
                                                 Expression operand)

Creates a STR_TO_MILLIS(expr) that will convert an ISO8601 datetime string into the number of milliseconds since the unix epoch. Valid date strings must start with a date in the form YYYY-MM-DD (time only strings are not supported).

Times can be of the form HH:MM, HH:MM:SS, or HH:MM:SS.FFF. Leading zero is not optional (i.e. 02 is ok, 2 is not). Hours are in 24-hour format. FFF represents milliseconds, and *trailing* zeros are optional (i.e. 5 == 500).

Time zones can be in one of three forms: (+/-)HH:MM (+/-)HHMM Z (which represents UTC)

Parameters:

operand - The string expression.

Returns:

The STR_TO_MILLIS(expr) function.

stringToUTC

@NonNull
public static Expression stringToUTC(@NonNull
                                              Expression operand)

Creates a STR_TO_UTC(expr) that will convert an ISO8601 datetime string into a full ISO8601 UTC datetime string. Valid date strings must start with a date in the form YYYY-MM-DD (time only strings are not supported).

Times can be of the form HH:MM, HH:MM:SS, or HH:MM:SS.FFF. Leading zero is not optional (i.e. 02 is ok, 2 is not). Hours are in 24-hour format. FFF represents milliseconds, and *trailing* zeros are optional (i.e. 5 == 500).

Time zones can be in one of three forms: (+/-)HH:MM (+/-)HHMM Z (which represents UTC)

Parameters:

operand - The string expression.

Returns:

The STR_TO_UTC(expr) function.