| /* |
| * 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.lang3; |
| |
| import java.util.Random; |
| import java.util.concurrent.ThreadLocalRandom; |
| |
| /** |
| * <p>Generates random {@link String}s.</p> |
| * |
| * <p><b>Caveat: Instances of {@link Random}, upon which the implementation of this |
| * class relies, are not cryptographically secure.</b></p> |
| * |
| * <p>RandomStringUtils is intended for simple use cases. For more advanced |
| * use cases consider using Apache Commons Text's |
| * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/RandomStringGenerator.html"> |
| * RandomStringGenerator</a> instead.</p> |
| * |
| * <p>The Apache Commons project provides |
| * <a href="https://commons.apache.org/rng">Commons RNG</a> dedicated to pseudo-random number generation, that may be |
| * a better choice for applications with more stringent requirements |
| * (performance and/or correctness).</p> |
| * |
| * <p>Note that <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> |
| * |
| * <p>#ThreadSafe#</p> |
| * @since 1.0 |
| */ |
| public class RandomStringUtils { |
| |
| private static ThreadLocalRandom random() { |
| return ThreadLocalRandom.current(); |
| } |
| |
| // 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(final 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 alpha-numeric |
| * characters as indicated by the arguments.</p> |
| * |
| * @param count the length of random string to create |
| * @param letters if {@code true}, generated string may include |
| * alphabetic characters |
| * @param numbers if {@code true}, generated string may include |
| * numeric characters |
| * @return the random string |
| */ |
| public static String random(final int count, final boolean letters, final 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 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} < 0. |
| */ |
| public static String random(final int count, final char... chars) { |
| if (chars == null) { |
| return random(count, 0, 0, false, false, null, random()); |
| } |
| return random(count, 0, chars.length, false, false, chars, random()); |
| } |
| |
| /** |
| * <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}, generated string may include |
| * alphabetic characters |
| * @param numbers if {@code true}, generated string may include |
| * numeric characters |
| * @return the random string |
| */ |
| public static String random(final int count, final int start, final int end, final boolean letters, final 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 if {@code true}, generated string may include |
| * alphabetic characters |
| * @param numbers if {@code true}, generated string may include |
| * numeric characters |
| * @param chars the set of chars to choose randoms from. |
| * If {@code null}, then it will use the set of all chars. |
| * @return the random string |
| * @throws ArrayIndexOutOfBoundsException if there are not |
| * {@code (end - start) + 1} characters in the set array. |
| */ |
| public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers, final 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}, start and end are set |
| * to {@code ' '} and {@code 'z'}, the ASCII printable |
| * characters, will be used, unless letters and numbers are both |
| * {@code false}, in which case, start and end are set to |
| * {@code 0} and {@link Character#MAX_CODE_POINT}. |
| * |
| * <p>If set is not {@code null}, 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 (inclusive) |
| * @param end the position in set of chars to end before (exclusive) |
| * @param letters if {@code true}, generated string may include |
| * alphabetic characters |
| * @param numbers if {@code true}, generated string may include |
| * numeric characters |
| * @param chars the set of chars to choose randoms from, must not be empty. |
| * If {@code null}, 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} characters in the set array. |
| * @throws IllegalArgumentException if {@code count} < 0 or the provided chars array is empty. |
| * @since 2.0 |
| */ |
| public static String random(int count, int start, int end, final boolean letters, final boolean numbers, |
| final char[] chars, final Random random) { |
| if (count == 0) { |
| return StringUtils.EMPTY; |
| } |
| if (count < 0) { |
| throw new IllegalArgumentException("Requested random string length " + count + " is less than 0."); |
| } |
| if (chars != null && chars.length == 0) { |
| throw new IllegalArgumentException("The chars array must not be empty"); |
| } |
| |
| if (start == 0 && end == 0) { |
| if (chars != null) { |
| end = chars.length; |
| } else if (!letters && !numbers) { |
| end = Character.MAX_CODE_POINT; |
| } else { |
| end = 'z' + 1; |
| start = ' '; |
| } |
| } else if (end <= start) { |
| throw new IllegalArgumentException("Parameter end (" + end + ") must be greater than start (" + start + ")"); |
| } |
| |
| final int zero_digit_ascii = 48; |
| final int first_letter_ascii = 65; |
| |
| if (chars == null && (numbers && end <= zero_digit_ascii |
| || letters && end <= first_letter_ascii)) { |
| throw new IllegalArgumentException("Parameter end (" + end + ") must be greater then (" + zero_digit_ascii + ") for generating digits " + |
| "or greater then (" + first_letter_ascii + ") for generating letters."); |
| } |
| |
| final StringBuilder builder = new StringBuilder(count); |
| final int gap = end - start; |
| |
| while (count-- != 0) { |
| final int codePoint; |
| if (chars == null) { |
| codePoint = random.nextInt(gap) + start; |
| |
| switch (Character.getType(codePoint)) { |
| case Character.UNASSIGNED: |
| case Character.PRIVATE_USE: |
| case Character.SURROGATE: |
| count++; |
| continue; |
| } |
| |
| } else { |
| codePoint = chars[random.nextInt(gap) + start]; |
| } |
| |
| final int numberOfChars = Character.charCount(codePoint); |
| if (count == 0 && numberOfChars > 1) { |
| count++; |
| continue; |
| } |
| |
| if (letters && Character.isLetter(codePoint) |
| || numbers && Character.isDigit(codePoint) |
| || !letters && !numbers) { |
| builder.appendCodePoint(codePoint); |
| |
| if (numberOfChars == 2) { |
| count--; |
| } |
| |
| } else { |
| count++; |
| } |
| } |
| return builder.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 by the string, must not be empty. |
| * If null, the set of all characters is used.</p> |
| * |
| * @param count the length of random string to create |
| * @param chars the String containing the set of characters to use, |
| * may be null, but must not be empty |
| * @return the random string |
| * @throws IllegalArgumentException if {@code count} < 0 or the string is empty. |
| */ |
| public static String random(final int count, final 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 Latin alphabetic |
| * characters (a-z, A-Z).</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAlphabetic(final int count) { |
| return random(count, true, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z).</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomAlphabetic(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomAlphabetic(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of Latin alphabetic |
| * characters (a-z, A-Z) and the digits 0-9.</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAlphanumeric(final int count) { |
| return random(count, true, true); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of Latin alphabetic |
| * characters (a-z, A-Z) and the digits 0-9.</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomAlphanumeric(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomAlphanumeric(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <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} and {@code 126} (inclusive).</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAscii(final int count) { |
| return random(count, 32, 127, false, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of characters whose |
| * ASCII value is between {@code 32} and {@code 126} (inclusive).</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomAscii(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomAscii(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters specified.</p> |
| * |
| * <p>Characters will be chosen from the set of characters which match the POSIX [:graph:] |
| * regular expression character class. This class contains all visible ASCII characters |
| * (i.e. anything except spaces and control characters).</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomGraph(final int count) { |
| return random(count, 33, 126, false, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of \p{Graph} characters.</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomGraph(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomGraph(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <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(final int count) { |
| return random(count, false, true); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of \p{Digit} characters.</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomNumeric(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomNumeric(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters specified.</p> |
| * |
| * <p>Characters will be chosen from the set of characters which match the POSIX [:print:] |
| * regular expression character class. This class includes all visible ASCII characters and spaces |
| * (i.e. anything except control characters).</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomPrint(final int count) { |
| return random(count, 32, 126, false, false); |
| } |
| |
| |
| /** |
| * <p>Creates a random string whose length is between the inclusive minimum and |
| * the exclusive maximum.</p> |
| * |
| * <p>Characters will be chosen from the set of \p{Print} characters.</p> |
| * |
| * @param minLengthInclusive the inclusive minimum length of the string to generate |
| * @param maxLengthExclusive the exclusive maximum length of the string to generate |
| * @return the random string |
| * @since 3.5 |
| */ |
| public static String randomPrint(final int minLengthInclusive, final int maxLengthExclusive) { |
| return randomPrint(RandomUtils.nextInt(minLengthInclusive, maxLengthExclusive)); |
| } |
| |
| /** |
| * <p>{@link RandomStringUtils} instances should NOT be constructed in |
| * standard programming. Instead, the class should be used as |
| * {@code RandomStringUtils.random(5);}.</p> |
| * |
| * <p>This constructor is public to permit tools that require a JavaBean instance |
| * to operate.</p> |
| */ |
| public RandomStringUtils() { |
| } |
| |
| } |