Java ThreadLocalRandom getRandomElement(E[] array)

Description

get Random Element

License

Open Source License

Declaration

public static <E> E getRandomElement(E[] array) 

Method Source Code

//package com.java2s;
/**//from w  w w  .  j ava  2s.c  om
 * The MIT License (MIT)
 * <p>
 * Copyright (c) 2016 Caratacus
 * <p>
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * <p>
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * <p>
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

import java.util.List;

import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;

public class Main {

    public static <E> E getRandomElement(E[] array) {
        return array[getRandomInt(array.length)];
    }

    public static <E> E getRandomElement(List<E> list) {
        return list.get(getRandomInt(list.size()));
    }

    public static <E> E getRandomElement(Set<E> set) {
        int randomInt = getRandomInt(set.size());
        int i = 0;
        for (E e : set) {
            if (i == randomInt) {
                return e;
            }
            i++;
        }
        return null;
    }

    public static int getRandomInt(int max) {
        return getRandom().nextInt(max);
    }

    public static int getRandomInt(int min, int max) {
        return getRandom().nextInt(max - min + 1) + min;
    }

    public static ThreadLocalRandom getRandom() {
        return ThreadLocalRandom.current();
    }
}

Related

1. getRandom(int p)
2. getRandom8()
3. getRandomBetween(int min, int max)
4. getRandomBoundedInt(int bound)
5. getRandomDouble(double a, double b)
6. getRandomElement(List elements)
7. getRandomFloat()
8. getRandomId(@Nonnull Random random, int length)
9. getRandomInt()