91 lines
2.3 KiB
Java
91 lines
2.3 KiB
Java
package com.github.javafaker.service;
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import java.util.List;
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import java.util.Random;
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public class RandomService {
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private static final Random SHARED_RANDOM = new Random();
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private final Random random;
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/**
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* Uses a default shared random.
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*/
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public RandomService() {
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this(SHARED_RANDOM);
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}
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/**
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* @param random If null is passed in, a default Random is assigned
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*/
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public RandomService(Random random) {
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this.random = random != null ? random : SHARED_RANDOM;
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}
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public int nextInt(int n) {
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return random.nextInt(n);
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}
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public long nextLong() {
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return random.nextLong();
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}
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// lifted from http://stackoverflow.com/questions/2546078/java-random-long-number-in-0-x-n-range
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public long nextLong(long n) {
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if (n <= 0) {
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throw new IllegalArgumentException("bound must be positive");
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}
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long bits, val;
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do {
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long randomLong = random.nextLong();
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bits = (randomLong << 1) >>> 1;
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val = bits % n;
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} while (bits - val + (n - 1) < 0L);
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return val;
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}
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public double nextDouble() {
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return random.nextDouble();
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}
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public Boolean nextBoolean() {
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return random.nextBoolean();
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}
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/**
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* Returns a random element from an array.
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*
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* @param array The array to take a random element fom.
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* @param <E> The type of the elements in the array.
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* @return A randomly selected element from the array.
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*/
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public <E> E nextElement(E[] array)
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{
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return array[this.nextInt(array.length)];
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}
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/**
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* Returns a random element from a list.
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*
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* @param list The list to take a random element fom.
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* @param <E> The type of the elements in the list.
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* @return A randomly selected element from the list.
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*/
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public <E> E nextElement(List<E> list)
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{
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return list.get(this.nextInt(list.size()));
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}
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/**
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* Returns a random enumeration value
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*
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* @param enumeration The enumberation to take a random value from
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* @param <E> The type of the enumeration
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* @return A randomly selected emumeration value
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*/
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public <E extends Enum<E>> E nextEnumValue(Class<E> enumeration)
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{
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return nextElement(enumeration.getEnumConstants());
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}
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}
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