org.uma.jmetal.util.pseudorandom

Interface RandomGenerator<Value>

Type Parameters:

Value - The type of value to generate

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface RandomGenerator<Value>

A RandomGenerator aims to provide a random value of a given type. Any value of this type can be generated.

A RandomGenerator is a FunctionalInterface. It is not intended to be directly implemented by a class, but instead to request a method for generating random values, usually by using lambda expressions.

Author:

Matthieu Vergne

Method Summary

Modifier and Type	Method and Description
static <T> RandomGenerator<T>	filter(RandomGenerator<T> generator, java.util.function.Predicate<T> filter) Reduce a RandomGenerator range.
static <T> RandomGenerator<T>	forArray(BoundedRandomGenerator<Integer> indexSelector, T... values) Create a RandomGenerator over an array based on a random selector.
static <T> RandomGenerator<T>	forCollection(BoundedRandomGenerator<Integer> indexSelector, Collection<T> values) Create a RandomGenerator over a Collection based on a random selector.
static <T extends Enum<T>> RandomGenerator<T>	forEnum(BoundedRandomGenerator<Integer> indexSelector, Class<T> enumClass) Create a RandomGenerator over Enum values based on a random selector.
Value	getRandomValue() Generate a random value.

Method Detail

getRandomValue

Value getRandomValue()

Generate a random value.

Returns:

the value generated

forCollection

static <T> RandomGenerator<T> forCollection(BoundedRandomGenerator<Integer> indexSelector,
                                            Collection<T> values)

Create a RandomGenerator over a Collection based on a random selector.

Parameters:

indexSelector - the random selector

values - the values to return

Returns:

a RandomGenerator on the provided values

forArray

@SafeVarargs
static <T> RandomGenerator<T> forArray(BoundedRandomGenerator<Integer> indexSelector,
                                                    T... values)

Create a RandomGenerator over an array based on a random selector.

Parameters:

indexSelector - the random selector

values - the values to return

Returns:

a RandomGenerator on the provided values

forEnum

static <T extends Enum<T>> RandomGenerator<T> forEnum(BoundedRandomGenerator<Integer> indexSelector,
                                                      Class<T> enumClass)

Create a RandomGenerator over Enum values based on a random selector.

Parameters:

indexSelector - the random selector

enumClass - the Enum to cover

Returns:

a RandomGenerator on the Enum values

filter

static <T> RandomGenerator<T> filter(RandomGenerator<T> generator,
                                     java.util.function.Predicate<T> filter)

Reduce a RandomGenerator range. The returned RandomGenerator uses the provided one to generate random values, but regenerate them if they do not pass the filter. Consequently, the initial RandomGenerator may be called several times o generate a single value. The impact on performance depends on the part of the distribution which is filtered out: if a significant part of the distribution is rejected, it might be more interesting to create a dedicated RandomGenerator.

Parameters:

generator - the RandomGenerator to filter

filter - the filter to pass to be an acceptable value

Returns:

a RandomGenerator which provides only acceptable values