| /* |
| * 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.commons.lang; |
| |
| import java.util.Random; |
| /** |
| * <p>Operations for random <code>String</code>s.</p> |
| * <p>Currently <em>private high surrogate</em> characters are ignored. |
| * These are unicode characters that fall between the values 56192 (db80) |
| * and 56319 (dbff) as we don't know how to handle them. |
| * High and low surrogates are correctly dealt with - that is if a |
| * high surrogate is randomly chosen, 55296 (d800) to 56191 (db7f) |
| * then it is followed by a low surrogate. If a low surrogate is chosen, |
| * 56320 (dc00) to 57343 (dfff) then it is placed after a randomly |
| * chosen high surrogate. </p> |
| * |
| * @author <a href="mailto:steven@caswell.name">Steven Caswell</a> |
| * @author Stephen Colebourne |
| * @author Gary Gregory |
| * @author Phil Steitz |
| * @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() { |
| super(); |
| } |
| |
| // 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> < 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; |
| } |
| } |
| |
| char[] buffer = new char[count]; |
| 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 && Character.isLetter(ch)) |
| || (numbers && Character.isDigit(ch)) |
| || (!letters && !numbers)) |
| { |
| if(ch >= 56320 && ch <= 57343) { |
| if(count == 0) { |
| count++; |
| } else { |
| // low surrogate, insert high surrogate after putting it in |
| buffer[count] = ch; |
| count--; |
| buffer[count] = (char) (55296 + random.nextInt(128)); |
| } |
| } else if(ch >= 55296 && ch <= 56191) { |
| if(count == 0) { |
| count++; |
| } else { |
| // high surrogate, insert low surrogate before putting it in |
| buffer[count] = (char) (56320 + random.nextInt(128)); |
| count--; |
| buffer[count] = ch; |
| } |
| } else if(ch >= 56192 && ch <= 56319) { |
| // private high surrogate, no effing clue, so skip it |
| count++; |
| } else { |
| buffer[count] = ch; |
| } |
| } else { |
| count++; |
| } |
| } |
| return new String(buffer); |
| } |
| |
| /** |
| * <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> < 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> < 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); |
| } |
| |
| } |
