org.oimutils.PasswordUtils.java Source code

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Here is the source code for org.oimutils.PasswordUtils.java

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/*
 * Copyright 2014 Jeremy Waters.
 * 
 * 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.
 */

package org.oimutils;

import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Utilities for working with OIM Passwords
 * 
 * @author WatersJeremy
 * 
 */
public class PasswordUtils {
    private static Log log = LogFactory.getLog(PasswordUtils.class);

    /**
     * Generates a random alphanumeric password that contains at least 1 upper, 1 lower, 1 digit; and excludes ambiguous
     * characters (e.g. 0/O, I/1/l)
     * 
     * @return password
     */
    public static String generatePassword() {
        int passwordLength = 8;
        char[] password = new char[passwordLength];

        // password chars with ambiguous characters removed (e.g. 0/O, I/1/l)
        String upper = "ABCDEFGHJKLMNPQRSTUVWXYZ";
        String lower = "abcdefghijkmnopqrstuvwxyz";
        String digit = "23456789";

        // set 1 of each upper/lower/digit
        fillPasswordChar(passwordLength, password, upper);
        fillPasswordChar(passwordLength, password, lower);
        fillPasswordChar(passwordLength, password, digit);

        // fill the remainder of the blanks in the password
        for (int i = 0; i < passwordLength; i++) {
            if (password[i] == '\0') {
                password[i] = getRandomChar(upper + lower + digit);
            }
        }

        return new String(password);
    }

    /**
     * fills one random character within the password with a random character chosen from the input set
     * 
     * @param passwordLength
     * @param password
     * @param upper
     */
    private static void fillPasswordChar(int passwordLength, char[] password, String string) {
        int pos;
        do {
            pos = (int) (Math.random() * passwordLength);
        } while (password[pos] != '\0');

        password[pos] = getRandomChar(string);
    }

    /**
     * gets a random character from the input set
     * 
     * @param string
     * @return
     */
    private static char getRandomChar(String string) {
        int pos = (int) (Math.random() * StringUtils.length(string));
        return CharUtils.toChar(StringUtils.substring(string, pos, pos + 1));
    }
}