water.util.fp

Class Functions

java.lang.Object

water.util.fp.Functions

Direct Known Subclasses:

PureFunctions

public class Functions
extends java.lang.Object

Operations on functions

Constructor Summary

Constructors

Constructor and Description
Functions()

Method Summary

Modifier and Type	Method and Description
static <X,Y,Z> Function<X,Z>	compose(Function<Y,Z> g, Function<X,Y> f)
static <X,Y> Function<X,Y>	constant(Y y)
static <X> Function<X,X>	identity()
static double	integrate(Function<java.lang.Integer,java.lang.Double> x, Function<java.lang.Integer,java.lang.Double> y, int from, int to) Integrates "area under curve" (assuming it exists), that is, for a parametric curve specified by functions x and y, defined on integer domain [from, to], calculate the area between x[from], x[to], horizontal axis, and the curve.
static <X,Y> java.lang.Iterable<Y>	map(java.lang.Iterable<X> xs, Function<X,Y> f)
static <T> Function<java.lang.Long,T>	onList(java.util.List<T> list)
static Unfoldable<java.lang.String,java.lang.String>	splitBy(java.lang.String separator)

Methods inherited from class java.lang.Object

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

Constructor Detail

Functions

public Functions()

Method Detail

compose

public static <X,Y,Z> Function<X,Z> compose(Function<Y,Z> g,
                                            Function<X,Y> f)

identity

public static <X> Function<X,X> identity()

onList

public static <T> Function<java.lang.Long,T> onList(java.util.List<T> list)

map

public static <X,Y> java.lang.Iterable<Y> map(java.lang.Iterable<X> xs,
                                              Function<X,Y> f)

constant

public static <X,Y> Function<X,Y> constant(Y y)

splitBy

public static Unfoldable<java.lang.String,java.lang.String> splitBy(java.lang.String separator)

integrate

public static double integrate(Function<java.lang.Integer,java.lang.Double> x,
                               Function<java.lang.Integer,java.lang.Double> y,
                               int from,
                               int to)

Integrates "area under curve" (assuming it exists), that is, for a parametric curve specified by functions x and y, defined on integer domain [from, to], calculate the area between x[from], x[to], horizontal axis, and the curve.

Parameters:

x - x-component of the curve

y - y-component of the curve

from - min value of the curve range

to - max value of the curve range

Returns:

the area under curve, the result of integrating x*y' over [from,to].