Java ThreadLocalRandom randomElement(Collection c, int n, boolean unique)

Description

Selects pseudo-random elements from a collection

License

Open Source License

Parameter

Parameter	Description
c	Collection to select from
n	Number of elements to select
unique	Whether the selection should be unique

Return

Random element(s) from collection

Declaration

public static <E> Collection<E> randomElement(Collection<E> c, int n, boolean unique) 

Method Source Code

//package com.java2s;
/*//from  w  w w.  j  av a  2  s  .c  o  m
 * Copyright (c) 2016.
 * This file is part of OFlib.
 *
 * OFlib is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * OFlib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with OFlib.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.util.*;
import java.util.concurrent.ThreadLocalRandom;

public class Main {
    /**
     * Selects pseudo-random elements from a collection
     *
     * @param c      Collection to select from
     * @param n      Number of elements to select
     * @param unique Whether the selection should be unique
     * @return Random element(s) from collection
     */
    public static <E> Collection<E> randomElement(Collection<E> c, int n, boolean unique) {
        List<E> out = new ArrayList<>();
        List<E> l = new ArrayList<>(c);

        while (out.size() < n) {
            E e = l.get(ThreadLocalRandom.current().nextInt(0, l.size()));
            out.add(e);
            if (unique)
                l.remove(e);
        }
        return out;
    }
}

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2. randomCase(String input)
3. randomChar()
4. randomDelay()
5. randomDouble(final double min, final double max)
6. randomEnum(Class clazz)
7. randomFishType()
8. randomFixedChars(int size, List pool)
9. randomIndexs(int count, int bound)