com.codelanx.commons.util

Class RNG

java.lang.Object

com.codelanx.commons.util.RNG

public final class RNG
extends Object

A class of random number generators that can be used instead of instantiating new Random classes all about the program

Since:

0.1.0

Version:

0.1.0

Author:

1Rogue

Field Summary

Fields

Modifier and Type	Field and Description
static Random	RAND A simple Random instance, should only be used on the program's main thread
static SecureRandom	SECURE_RAND Represents a SecureRandom with a new, randomly generated seed of a pseudo-random bitlength every 10 minutes.

Method Summary

Modifier and Type	Method and Description
static <T> T	get(Collection<T> collection) Returns a random element from a collection
static <T> List<T>	get(Collection<T> collection, int amount) Returns a list of random, unique elements from a collection
static <T> T	getFromWeightedMap(Map<T,Double> weights) Returns a random variable from a weighted map, which is a map of objects to their respective probabilities.
static ThreadLocalRandom	THREAD_LOCAL() Returns the ThreadLocalRandom specific to the calling thread

Methods inherited from class java.lang.Object

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

Field Detail

RAND

public static final Random RAND

A simple Random instance, should only be used on the program's main thread

Since:

0.1.0

SECURE_RAND

public static final SecureRandom SECURE_RAND

Represents a SecureRandom with a new, randomly generated seed of a pseudo-random bitlength every 10 minutes.

Since:

0.1.0

Method Detail

THREAD_LOCAL

public static final ThreadLocalRandom THREAD_LOCAL()

Returns the ThreadLocalRandom specific to the calling thread

Returns:

The ThreadLocalRandom for the current thread context

Since:

0.1.0

get

public static <T> T get(Collection<T> collection)

Returns a random element from a collection

Type Parameters:

T - The type of the collection and returned element

Parameters:

collection - The Collection to get an element from

Returns:

A random element

Since:

0.2.0

get

public static <T> List<T> get(Collection<T> collection,
                              int amount)

Returns a list of random, unique elements from a collection

Type Parameters:

T - The type of the elements in the collection, and what's returned

Parameters:

collection - The Collection to get elements from

amount - The amount of elements to retrieve

Returns:

A List of unique, random elements

Throws:

IllegalArgumentException - If amount > collection#size

IllegalArgumentException - If collection is null

Since:

0.2.0

getFromWeightedMap

public static <T> T getFromWeightedMap(Map<T,Double> weights)

Returns a random variable from a weighted map, which is a map of objects to their respective probabilities. An example would be a map of 5 objects, all mapped to 1, 2, 3, 4 and 5. Their respective probabilities would be weight/map weight, where map weight is the sum of all the weights in the map. The weights do not have to add up to 1 or 100 or any arbitrary number.

Type Parameters:

T - The type of the objects being weighted in the Map

Parameters:

weights - A Map<T, Double> of weighted objects

Returns:

A randomly selected variable, based on the probabilities from the provided Map

Since:

0.3.1