Java Random random(final char[] chars)

Description

Returns a random character from a sequence of characters.

License

Apache License

Parameter

Parameter	Description
chars	the sequence of characters

Return

the random character

Declaration

public static char random(final char[] chars) 

Method Source Code

//package com.java2s;
/**// ww w.j a v  a 2 s  .  c om
 *    Copyright 2013-2016 PayStax, LLC
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

import java.util.*;

public class Main {
    private static Random rand = new Random();
    public static char[] alphaNumeric = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
            .toCharArray();

    /**
     * Returns a random character from a sequence of characters.
     *
     * @param chars the sequence of characters
     * @return the random character
     */
    public static char random(final char[] chars) {
        int idx = rand.nextInt(chars.length);
        return chars[idx];
    }

    /**
     * Chooses a random number between min inclusive and max inclusive.
     *
     * @param min the minimim number
     * @param max the maximum number
     * @return the randon number
     */
    public static int random(int min, int max) {
        if (min == max) {
            return 1;
        }
        if (min > max) {
            throw new IllegalArgumentException("max must be greater than or equal to min");
        }
        return rand.nextInt(max - min) + min;
    }

    /**
     * Generates a random string.
     *
     * @param min the minimum number of characters allowed
     * @param max the maximum number of characters allowed
     * @param chars the characters to choose from or null
     * @return the random string
     */
    public static String random(final int min, final int max, char[] chars) {
        if (chars == null) {
            chars = alphaNumeric;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i <= random(min, max); i++) {
            sb.append(random(chars));
        }
        return sb.toString();
    }
}

Related

1. random()
2. random()
3. random()
4. random()
5. random(E[] elements)
6. random(float min, float max)
7. random(float theStart, float theEnd)
8. random(int min, int max)
9. random(List list, Random random)