Java ThreadLocalRandom rand(final Collection items)

Description

rand

License

Open Source License

Parameter

Parameter	Description
items	items, from which one is to be randed
E	class of the provided items and the desired returned one

Return

a random item of the provided ones

Declaration

public static <E> E rand(final Collection<E> items) 

Method Source Code

//package com.java2s;
/*/* ww w  .j  a  v a  2  s. c  om*/
 * Copyright (C) 2017 Dennis Neufeld
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.util.Collection;

import java.util.concurrent.ThreadLocalRandom;

public class Main {
    /**
     * @param items items, from which one is to be randed
     * @param <E>   class of the provided items and the desired returned one
     * @return a random item of the provided ones
     */
    public static <E> E rand(final Collection<E> items) {
        if (items.isEmpty()) {
            throw new IllegalArgumentException("Can't pick an item from zero items.");
        }
        final int rand = ThreadLocalRandom.current().nextInt(items.size());
        int i = 0;
        E result = null;
        for (final E item : items) {
            if (i == rand) {
                result = item;
                break;
            }
            i++;
        }
        return result;
    }
}

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5. parseSeed(String seedString)
6. randInt(int min, int max)
7. random()
8. random()
9. random()