diff options
Diffstat (limited to 'src/main/java/org/apache/commons/lang3/RandomStringUtils.java')
| -rw-r--r-- | src/main/java/org/apache/commons/lang3/RandomStringUtils.java | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/lang3/RandomStringUtils.java b/src/main/java/org/apache/commons/lang3/RandomStringUtils.java new file mode 100644 index 000000000..798542034 --- /dev/null +++ b/src/main/java/org/apache/commons/lang3/RandomStringUtils.java @@ -0,0 +1,475 @@ +/* + * 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; + +/** + * Generates random {@link String}s. + * + * <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/proper/commons-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 + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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()); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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()); + } + + /** + * Creates a random string based on a variety of options, using + * default source of randomness. + * + * <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()); + } + + /** + * Creates a random string based on a variety of options, using + * supplied source of randomness. + * + * <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(); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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()); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * Creates a random string whose length is the number of characters specified. + * + * <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); + } + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * Creates a random string whose length is the number of characters + * specified. + * + * <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); + } + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * Creates a random string whose length is the number of characters specified. + * + * <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); + } + + + /** + * Creates a random string whose length is between the inclusive minimum and + * the exclusive maximum. + * + * <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)); + } + + /** + * {@link RandomStringUtils} instances should NOT be constructed in + * standard programming. Instead, the class should be used as + * {@code RandomStringUtils.random(5);}. + * + * <p>This constructor is public to permit tools that require a JavaBean instance + * to operate.</p> + */ + public RandomStringUtils() { + } + +} |