/*/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements.  See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.apache.pluto.internal.impl;import java.util.Random;/** * <strong>Copied from commons-lang. No need for dependency.</strong> * * <p>Operations for random <code>String</code>s.</p> * * @since 1.0 * @version $Id$ */public class RandomStringUtils {    /**     * <p>Random object used by random method. This has to be not local     * to the random method so as to not return the same value in the     * same millisecond.</p>     */    private static final Random RANDOM = new Random();    /**     * <p><code>RandomStringUtils</code> instances should NOT be constructed in     * standard programming. Instead, the class should be used as     * <code>RandomStringUtils.random(5);</code>.</p>     *     * <p>This constructor is public to permit tools that require a JavaBean instance     * to operate.</p>     */    public RandomStringUtils() {    }    // Random    //-----------------------------------------------------------------------    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of all characters.</p>     *     * @param count  the length of random string to create     * @return the random string     */    public static String random(int count) {        return random(count, false, false);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of characters whose     * ASCII value is between <code>32</code> and <code>126</code> (inclusive).</p>     *     * @param count  the length of random string to create     * @return the random string     */    public static String randomAscii(int count) {        return random(count, 32, 127, false, false);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of alphabetic     * characters.</p>     *     * @param count  the length of random string to create     * @return the random string     */    public static String randomAlphabetic(int count) {        return random(count, true, false);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of alpha-numeric     * characters.</p>     *     * @param count  the length of random string to create     * @return the random string     */    public static String randomAlphanumeric(int count) {        return random(count, true, true);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of numeric     * characters.</p>     *     * @param count  the length of random string to create     * @return the random string     */    public static String randomNumeric(int count) {        return random(count, false, true);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of alpha-numeric     * characters as indicated by the arguments.</p>     *     * @param count  the length of random string to create     * @param letters  if <code>true</code>, generated string will include     *  alphabetic characters     * @param numbers  if <code>true</code>, generated string will include     *  numeric characters     * @return the random string     */    public static String random(int count, boolean letters, boolean numbers) {        return random(count, 0, 0, letters, numbers);    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of alpha-numeric     * characters as indicated by the arguments.</p>     *     * @param count  the length of random string to create     * @param start  the position in set of chars to start at     * @param end  the position in set of chars to end before     * @param letters  if <code>true</code>, generated string will include     *  alphabetic characters     * @param numbers  if <code>true</code>, generated string will include     *  numeric characters     * @return the random string     */    public static String random(int count, int start, int end, boolean letters, boolean numbers) {        return random(count, start, end, letters, numbers, null, RANDOM);    }    /**     * <p>Creates a random string based on a variety of options, using     * default source of randomness.</p>     *     * <p>This method has exactly the same semantics as     * {@link #random(int,int,int,boolean,boolean,char[],Random)}, but     * instead of using an externally supplied source of randomness, it uses     * the internal static {@link Random} instance.</p>     *     * @param count  the length of random string to create     * @param start  the position in set of chars to start at     * @param end  the position in set of chars to end before     * @param letters  only allow letters?     * @param numbers  only allow numbers?     * @param chars  the set of chars to choose randoms from.     *  If <code>null</code>, then it will use the set of all chars.     * @return the random string     * @throws ArrayIndexOutOfBoundsException if there are not     *  <code>(end - start) + 1</code> characters in the set array.     */    public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] chars) {        return random(count, start, end, letters, numbers, chars, RANDOM);    }    /**     * <p>Creates a random string based on a variety of options, using     * supplied source of randomness.</p>     *     * <p>If start and end are both <code>0</code>, start and end are set     * to <code>' '</code> and <code>'z'</code>, the ASCII printable     * characters, will be used, unless letters and numbers are both     * <code>false</code>, in which case, start and end are set to     * <code>0</code> and <code>Integer.MAX_VALUE</code>.     *     * <p>If set is not <code>null</code>, characters between start and     * end are chosen.</p>     *     * <p>This method accepts a user-supplied {@link Random}     * instance to use as a source of randomness. By seeding a single     * {@link Random} instance with a fixed seed and using it for each call,     * the same random sequence of strings can be generated repeatedly     * and predictably.</p>     *     * @param count  the length of random string to create     * @param start  the position in set of chars to start at     * @param end  the position in set of chars to end before     * @param letters  only allow letters?     * @param numbers  only allow numbers?     * @param chars  the set of chars to choose randoms from.     *  If <code>null</code>, then it will use the set of all chars.     * @param random  a source of randomness.     * @return the random string     * @throws ArrayIndexOutOfBoundsException if there are not     *  <code>(end - start) + 1</code> characters in the set array.     * @throws IllegalArgumentException if <code>count</code> &lt; 0.     * @since 2.0     */    public static String random(int count, int start, int end, boolean letters, boolean numbers,                                char[] chars, Random random) {        if (count == 0) {            return "";        } else if (count < 0) {            throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");        }        if ((start == 0) && (end == 0)) {            end = 'z' + 1;            start = ' ';            if (!letters && !numbers) {                start = 0;                end = Integer.MAX_VALUE;            }        }        StringBuffer buffer = new StringBuffer();        int gap = end - start;        while (count-- != 0) {            char ch;            if (chars == null) {                ch = (char) (random.nextInt(gap) + start);            } else {                ch = chars[random.nextInt(gap) + start];            }            if ((letters && numbers && Character.isLetterOrDigit(ch))                || (letters && Character.isLetter(ch))                || (numbers && Character.isDigit(ch))                || (!letters && !numbers)) {                buffer.append(ch);            } else {                count++;            }        }        return buffer.toString();    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of characters     * specified.</p>     *     * @param count  the length of random string to create     * @param chars  the String containing the set of characters to use,     *  may be null     * @return the random string     * @throws IllegalArgumentException if <code>count</code> &lt; 0.     */    public static String random(int count, String chars) {        if (chars == null) {            return random(count, 0, 0, false, false, null, RANDOM);        }        return random(count, chars.toCharArray());    }    /**     * <p>Creates a random string whose length is the number of characters     * specified.</p>     *     * <p>Characters will be chosen from the set of characters specified.</p>     *     * @param count  the length of random string to create     * @param chars  the character array containing the set of characters to use,     *  may be null     * @return the random string     * @throws IllegalArgumentException if <code>count</code> &lt; 0.     */    public static String random(int count, char[] chars) {        if (chars == null) {            return random(count, 0, 0, false, false, null, RANDOM);        }        return random(count, 0, chars.length, false, false, chars, RANDOM);    }}