Java ThreadLocalRandom base62Random()

Description

base Random

License

BSD License

Declaration

public static String base62Random() 

Method Source Code

//package com.java2s;
//License from project: BSD License 

import java.util.concurrent.ThreadLocalRandom;

public class Main {
    public static String base62Random() {
        return base62ToString(Math.abs(ThreadLocalRandom.current().nextLong()));
    }//from ww w  .ja  va2s . co  m

    private static String base62ToString(long value) {
        // Divides the number by 64, so how many 64s are in
        // 'value'. This number is stored in Y.
        // e.g #1
        // 1) 1000 / 62 = 16, plus 8 remainder (stored in x).
        // 2) 16 / 62 = 0, remainder 16
        // 3) 16, 8 or G8:
        // 4) 65 is A, add 6 to this = 71 or G.
        //
        // e.g #2:
        // 1) 10000 / 62 = 161, remainder 18
        // 2) 161 / 62 = 2, remainder 37
        // 3) 2 / 62 = 0, remainder 2
        // 4) 2, 37, 18, or 2,b,I:
        // 5) 65 is A, add 27 to this (minus 10 from 37 as these are digits) = 92.
        // Add 6 to 92, as 91-96 are symbols. 98 is b.
        // 6)
        long x = value % 62L;
        long y = value / 62L;
        if (y > 0) {
            return base62ToString(y) + valToChar(x);
        }
        return new Character(valToChar(x)).toString();
    }

    private static char valToChar(long value) {
        if (value > 9) {
            int ascii = (65 + ((int) value - 10));
            if (ascii > 90)
                ascii += 6;
            return (char) ascii;
        } else {
            return String.valueOf(value).charAt(0);
        }
    }
}

Related

1. createNewPin()
2. createRandom(int number)
3. createRandomName()
4. createRandomNumbers(int length)