RandomStringUtils.java

  1. /*
  2.  * Licensed to the Apache Software Foundation (ASF) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * The ASF licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *      http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.apache.commons.lang3;

  19. import java.security.SecureRandom;
  20. import java.security.Security;
  21. import java.util.Random;
  22. import java.util.concurrent.ThreadLocalRandom;
  23. import java.util.function.Supplier;

  25. /**
  26.  * Generates random {@link String}s.
  27.  * <p>
  28.  * Use {@link #secure()} to get the singleton instance based on {@link SecureRandom#SecureRandom()} which uses a secure random number generator implementing the
  29.  * default random number algorithm.
  30.  * </p>
  31.  * <p>
  32.  * Use {@link #secureStrong()} to get the singleton instance based on {@link SecureRandom#getInstanceStrong()} which uses an instance that was selected by using
  33.  * the algorithms/providers specified in the {@code securerandom.strongAlgorithms} {@link Security} property.
  34.  * </p>
  35.  * <p>
  36.  * Use {@link #insecure()} to get the singleton instance based on {@link ThreadLocalRandom#current()} <b>which is not cryptographically secure</b>. In addition,
  37.  * instances do not use a cryptographically random seed unless the {@linkplain System#getProperty system property} {@code java.util.secureRandomSeed} is set to
  38.  * {@code true}.
  39.  * </p>
  40.  * <p>
  41.  * Starting in version 3.17.0, the method {@link #secure()} uses {@link SecureRandom#SecureRandom()} instead of {@link SecureRandom#getInstanceStrong()}, and
  42.  * adds {@link #secureStrong()}.
  43.  * </p>
  44.  * <p>
  45.  * Starting in version 3.16.0, this class uses {@link #secure()} for static methods and adds {@link #insecure()}.
  46.  * </p>
  47.  * <p>
  48.  * Starting in version 3.15.0, this class uses {@link SecureRandom#getInstanceStrong()} for static methods.
  49.  * </p>
  50.  * <p>
  51.  * Before version 3.15.0, this class used {@link ThreadLocalRandom#current()} for static methods, which is not cryptographically secure.
  52.  * </p>
  53.  * <p>
  54.  * RandomStringUtils is intended for simple use cases. For more advanced use cases consider using Apache Commons Text's
  55.  * <a href= "https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/RandomStringGenerator.html"> RandomStringGenerator</a>
  56.  * instead.
  57.  * </p>
  58.  * <p>
  59.  * The Apache Commons project provides <a href="https://commons.apache.org/proper/commons-rng/">Commons RNG</a> dedicated to pseudo-random number generation,
  60.  * that may be a better choice for applications with more stringent requirements (performance and/or correctness).
  61.  * </p>
  62.  * <p>
  63.  * 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
  64.  * 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
  65.  * (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
  66.  * surrogate.
  67.  * </p>
  68.  * <p>
  69.  * #ThreadSafe#
  70.  * </p>
  71.  *
  72.  * @see #secure()
  73.  * @see #secureStrong()
  74.  * @see #insecure()
  75.  * @see SecureRandom#SecureRandom()
  76.  * @see SecureRandom#getInstanceStrong()
  77.  * @see ThreadLocalRandom#current()
  78.  * @see RandomUtils
  79.  * @since 1.0
  80.  */
  81. public class RandomStringUtils {

  83.     private static final Supplier<RandomUtils> SECURE_SUPPLIER = RandomUtils::secure;

  85.     private static RandomStringUtils INSECURE = new RandomStringUtils(RandomUtils::insecure);

  87.     private static RandomStringUtils SECURE = new RandomStringUtils(SECURE_SUPPLIER);

  89.     private static RandomStringUtils SECURE_STRONG = new RandomStringUtils(RandomUtils::secureStrong);

  91.     private static final char[] ALPHANUMERICAL_CHARS = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',
  92.             'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
  93.             'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1',
  94.             '2', '3', '4', '5', '6', '7', '8', '9' };

  96.     /**
  97.      * Gets the singleton instance based on {@link ThreadLocalRandom#current()}; <b>which is not cryptographically
  98.      * secure</b>; use {@link #secure()} to use an algorithms/providers specified in the
  99.      * {@code securerandom.strongAlgorithms} {@link Security} property.
  100.      * <p>
  101.      * The method {@link ThreadLocalRandom#current()} is called on-demand.
  102.      * </p>
  103.      *
  104.      * @return the singleton instance based on {@link ThreadLocalRandom#current()}.
  105.      * @see ThreadLocalRandom#current()
  106.      * @see #secure()
  107.      * @since 3.16.0
  108.      */
  109.     public static RandomStringUtils insecure() {
  110.         return INSECURE;
  111.     }

  113.     /**
  114.      * Creates a random string whose length is the number of characters specified.
  115.      *
  116.      * <p>
  117.      * Characters will be chosen from the set of all characters.
  118.      * </p>
  119.      *
  120.      * @param count the length of random string to create
  121.      * @return the random string
  122.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  123.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  124.      */
  125.     @Deprecated
  126.     public static String random(final int count) {
  127.         return secure().next(count);
  128.     }

  130.     /**
  131.      * Creates a random string whose length is the number of characters specified.
  132.      *
  133.      * <p>
  134.      * Characters will be chosen from the set of alpha-numeric characters as indicated by the arguments.
  135.      * </p>
  136.      *
  137.      * @param count   the length of random string to create
  138.      * @param letters if {@code true}, generated string may include alphabetic characters
  139.      * @param numbers if {@code true}, generated string may include numeric characters
  140.      * @return the random string
  141.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  142.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  143.      */
  144.     @Deprecated
  145.     public static String random(final int count, final boolean letters, final boolean numbers) {
  146.         return secure().next(count, letters, numbers);
  147.     }

  149.     /**
  150.      * Creates a random string whose length is the number of characters specified.
  151.      *
  152.      * <p>
  153.      * Characters will be chosen from the set of characters specified.
  154.      * </p>
  155.      *
  156.      * @param count the length of random string to create
  157.      * @param chars the character array containing the set of characters to use, may be null
  158.      * @return the random string
  159.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  160.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  161.      */
  162.     @Deprecated
  163.     public static String random(final int count, final char... chars) {
  164.         return secure().next(count, chars);
  165.     }

  167.     /**
  168.      * Creates a random string whose length is the number of characters specified.
  169.      *
  170.      * <p>
  171.      * Characters will be chosen from the set of alpha-numeric characters as indicated by the arguments.
  172.      * </p>
  173.      *
  174.      * @param count   the length of random string to create
  175.      * @param start   the position in set of chars to start at
  176.      * @param end     the position in set of chars to end before
  177.      * @param letters if {@code true}, generated string may include alphabetic characters
  178.      * @param numbers if {@code true}, generated string may include numeric characters
  179.      * @return the random string
  180.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  181.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  182.      */
  183.     @Deprecated
  184.     public static String random(final int count, final int start, final int end, final boolean letters,
  185.             final boolean numbers) {
  186.         return secure().next(count, start, end, letters, numbers);
  187.     }

  189.     /**
  190.      * Creates a random string based on a variety of options, using default source of randomness.
  191.      *
  192.      * <p>
  193.      * This method has exactly the same semantics as {@link #random(int,int,int,boolean,boolean,char[],Random)}, but
  194.      * instead of using an externally supplied source of randomness, it uses the internal static {@link Random}
  195.      * instance.
  196.      * </p>
  197.      *
  198.      * @param count   the length of random string to create
  199.      * @param start   the position in set of chars to start at
  200.      * @param end     the position in set of chars to end before
  201.      * @param letters if {@code true}, generated string may include alphabetic characters
  202.      * @param numbers if {@code true}, generated string may include numeric characters
  203.      * @param chars   the set of chars to choose randoms from. If {@code null}, then it will use the set of all chars.
  204.      * @return the random string
  205.      * @throws ArrayIndexOutOfBoundsException if there are not {@code (end - start) + 1} characters in the set array.
  206.      * @throws IllegalArgumentException       if {@code count} &lt; 0.
  207.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  208.      */
  209.     @Deprecated
  210.     public static String random(final int count, final int start, final int end, final boolean letters,
  211.             final boolean numbers, final char... chars) {
  212.         return secure().next(count, start, end, letters, numbers, chars);
  213.     }

  215.     /**
  216.      * Creates a random string based on a variety of options, using supplied source of randomness.
  217.      *
  218.      * <p>
  219.      * If start and end are both {@code 0}, start and end are set to {@code ' '} and {@code 'z'}, the ASCII printable
  220.      * characters, will be used, unless letters and numbers are both {@code false}, in which case, start and end are set
  221.      * to {@code 0} and {@link Character#MAX_CODE_POINT}.
  222.      *
  223.      * <p>
  224.      * If set is not {@code null}, characters between start and end are chosen.
  225.      * </p>
  226.      *
  227.      * <p>
  228.      * This method accepts a user-supplied {@link Random} instance to use as a source of randomness. By seeding a single
  229.      * {@link Random} instance with a fixed seed and using it for each call, the same random sequence of strings can be
  230.      * generated repeatedly and predictably.
  231.      * </p>
  232.      *
  233.      * @param count   the length of random string to create
  234.      * @param start   the position in set of chars to start at (inclusive)
  235.      * @param end     the position in set of chars to end before (exclusive)
  236.      * @param letters if {@code true}, generated string may include alphabetic characters
  237.      * @param numbers if {@code true}, generated string may include numeric characters
  238.      * @param chars   the set of chars to choose randoms from, must not be empty. If {@code null}, then it will use the
  239.      *                set of all chars.
  240.      * @param random  a source of randomness.
  241.      * @return the random string
  242.      * @throws ArrayIndexOutOfBoundsException if there are not {@code (end - start) + 1} characters in the set array.
  243.      * @throws IllegalArgumentException       if {@code count} &lt; 0 or the provided chars array is empty.
  244.      * @since 2.0
  245.      */
  246.     public static String random(int count, int start, int end, final boolean letters, final boolean numbers,
  247.             final char[] chars, final Random random) {
  248.         if (count == 0) {
  249.             return StringUtils.EMPTY;
  250.         }
  251.         if (count < 0) {
  252.             throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");
  253.         }
  254.         if (chars != null && chars.length == 0) {
  255.             throw new IllegalArgumentException("The chars array must not be empty");
  256.         }

  258.         if (start == 0 && end == 0) {
  259.             if (chars != null) {
  260.                 end = chars.length;
  261.             } else if (!letters && !numbers) {
  262.                 end = Character.MAX_CODE_POINT;
  263.             } else {
  264.                 end = 'z' + 1;
  265.                 start = ' ';
  266.             }
  267.         } else if (end <= start) {
  268.             throw new IllegalArgumentException(
  269.                     "Parameter end (" + end + ") must be greater than start (" + start + ")");
  270.         } else if (start < 0 || end < 0) {
  271.             throw new IllegalArgumentException("Character positions MUST be >= 0");
  272.         }

  274.         if (end > Character.MAX_CODE_POINT) {
  275.             // Technically, it should be `Character.MAX_CODE_POINT+1` as `end` is excluded
  276.             // But the character `Character.MAX_CODE_POINT` is private use, so it would anyway be excluded
  277.             end = Character.MAX_CODE_POINT;
  278.         }

  280.         // Optimize generation of full alphanumerical characters
  281.         // Normally, we would need to pick a 7-bit integer, since gap = 'z' - '0' + 1 = 75 > 64
  282.         // In turn, this would make us reject the sampling with probability 1 - 62 / 2^7 > 1 / 2
  283.         // Instead we can pick directly from the right set of 62 characters, which requires
  284.         // picking a 6-bit integer and only rejecting with probability 2 / 64 = 1 / 32
  285.         if (chars == null && letters && numbers && start <= '0' && end >= 'z' + 1) {
  286.             return random(count, 0, 0, false, false, ALPHANUMERICAL_CHARS, random);
  287.         }

  289.         // Optimize start and end when filtering by letters and/or numbers:
  290.         // The range provided may be too large since we filter anyway afterward.
  291.         // Note the use of Math.min/max (as opposed to setting start to '0' for example),
  292.         // since it is possible the range start/end excludes some of the letters/numbers,
  293.         // e.g., it is possible that start already is '1' when numbers = true, and start
  294.         // needs to stay equal to '1' in that case.
  295.         if (chars == null) {
  296.             if (letters && numbers) {
  297.                 start = Math.max('0', start);
  298.                 end = Math.min('z' + 1, end);
  299.             } else if (numbers) {
  300.                 // just numbers, no letters
  301.                 start = Math.max('0', start);
  302.                 end = Math.min('9' + 1, end);
  303.             } else if (letters) {
  304.                 // just letters, no numbers
  305.                 start = Math.max('A', start);
  306.                 end = Math.min('z' + 1, end);
  307.             }
  308.         }

  310.         final int zeroDigitAscii = 48;
  311.         final int firstLetterAscii = 65;

  313.         if (chars == null && (numbers && end <= zeroDigitAscii || letters && end <= firstLetterAscii)) {
  314.             throw new IllegalArgumentException(
  315.                     "Parameter end (" + end + ") must be greater then (" + zeroDigitAscii + ") for generating digits "
  316.                             + "or greater then (" + firstLetterAscii + ") for generating letters.");
  317.         }

  319.         final StringBuilder builder = new StringBuilder(count);
  320.         final int gap = end - start;
  321.         final int gapBits = Integer.SIZE - Integer.numberOfLeadingZeros(gap);
  322.         // The size of the cache we use is an heuristic:
  323.         // about twice the number of bytes required if no rejection
  324.         // Ideally the cache size depends on multiple factor, including the cost of generating x bytes
  325.         // of randomness as well as the probability of rejection. It is however not easy to know
  326.         // those values programmatically for the general case.
  327.         final CachedRandomBits arb = new CachedRandomBits((count * gapBits + 3) / 5 + 10, random);

  329.         while (count-- != 0) {
  330.             // Generate a random value between start (included) and end (excluded)
  331.             final int randomValue = arb.nextBits(gapBits) + start;
  332.             // Rejection sampling if value too large
  333.             if (randomValue >= end) {
  334.                 count++;
  335.                 continue;
  336.             }

  338.             final int codePoint;
  339.             if (chars == null) {
  340.                 codePoint = randomValue;

  342.                 switch (Character.getType(codePoint)) {
  343.                 case Character.UNASSIGNED:
  344.                 case Character.PRIVATE_USE:
  345.                 case Character.SURROGATE:
  346.                     count++;
  347.                     continue;
  348.                 }

  350.             } else {
  351.                 codePoint = chars[randomValue];
  352.             }

  354.             final int numberOfChars = Character.charCount(codePoint);
  355.             if (count == 0 && numberOfChars > 1) {
  356.                 count++;
  357.                 continue;
  358.             }

  360.             if (letters && Character.isLetter(codePoint) || numbers && Character.isDigit(codePoint)
  361.                     || !letters && !numbers) {
  362.                 builder.appendCodePoint(codePoint);

  364.                 if (numberOfChars == 2) {
  365.                     count--;
  366.                 }

  368.             } else {
  369.                 count++;
  370.             }
  371.         }
  372.         return builder.toString();
  373.     }

  375.     /**
  376.      * Creates a random string whose length is the number of characters specified.
  377.      *
  378.      * <p>
  379.      * Characters will be chosen from the set of characters specified by the string, must not be empty. If null, the set
  380.      * of all characters is used.
  381.      * </p>
  382.      *
  383.      * @param count the length of random string to create
  384.      * @param chars the String containing the set of characters to use, may be null, but must not be empty
  385.      * @return the random string
  386.      * @throws IllegalArgumentException if {@code count} &lt; 0 or the string is empty.
  387.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  388.      */
  389.     @Deprecated
  390.     public static String random(final int count, final String chars) {
  391.         return secure().next(count, chars);
  392.     }

  394.     /**
  395.      * Creates a random string whose length is the number of characters specified.
  396.      *
  397.      * <p>
  398.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z).
  399.      * </p>
  400.      *
  401.      * @param count the length of random string to create
  402.      * @return the random string
  403.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  404.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  405.      */
  406.     @Deprecated
  407.     public static String randomAlphabetic(final int count) {
  408.         return secure().nextAlphabetic(count);
  409.     }

  411.     /**
  412.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  413.      *
  414.      * <p>
  415.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z).
  416.      * </p>
  417.      *
  418.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  419.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  420.      * @return the random string
  421.      * @since 3.5
  422.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  423.      */
  424.     @Deprecated
  425.     public static String randomAlphabetic(final int minLengthInclusive, final int maxLengthExclusive) {
  426.         return secure().nextAlphabetic(minLengthInclusive, maxLengthExclusive);
  427.     }

  429.     /**
  430.      * Creates a random string whose length is the number of characters specified.
  431.      *
  432.      * <p>
  433.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z) and the digits 0-9.
  434.      * </p>
  435.      *
  436.      * @param count the length of random string to create
  437.      * @return the random string
  438.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  439.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  440.      */
  441.     @Deprecated
  442.     public static String randomAlphanumeric(final int count) {
  443.         return secure().nextAlphanumeric(count);
  444.     }

  446.     /**
  447.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  448.      *
  449.      * <p>
  450.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z) and the digits 0-9.
  451.      * </p>
  452.      *
  453.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  454.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  455.      * @return the random string
  456.      * @since 3.5
  457.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  458.      */
  459.     @Deprecated
  460.     public static String randomAlphanumeric(final int minLengthInclusive, final int maxLengthExclusive) {
  461.         return secure().nextAlphanumeric(minLengthInclusive, maxLengthExclusive);
  462.     }

  464.     /**
  465.      * Creates a random string whose length is the number of characters specified.
  466.      *
  467.      * <p>
  468.      * Characters will be chosen from the set of characters whose ASCII value is between {@code 32} and {@code 126}
  469.      * (inclusive).
  470.      * </p>
  471.      *
  472.      * @param count the length of random string to create
  473.      * @return the random string
  474.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  475.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  476.      */
  477.     @Deprecated
  478.     public static String randomAscii(final int count) {
  479.         return secure().nextAscii(count);
  480.     }

  482.     /**
  483.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  484.      *
  485.      * <p>
  486.      * Characters will be chosen from the set of characters whose ASCII value is between {@code 32} and {@code 126}
  487.      * (inclusive).
  488.      * </p>
  489.      *
  490.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  491.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  492.      * @return the random string
  493.      * @since 3.5
  494.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  495.      */
  496.     @Deprecated
  497.     public static String randomAscii(final int minLengthInclusive, final int maxLengthExclusive) {
  498.         return secure().nextAscii(minLengthInclusive, maxLengthExclusive);
  499.     }

  501.     /**
  502.      * Creates a random string whose length is the number of characters specified.
  503.      *
  504.      * <p>
  505.      * Characters will be chosen from the set of characters which match the POSIX [:graph:] regular expression character
  506.      * class. This class contains all visible ASCII characters (i.e. anything except spaces and control characters).
  507.      * </p>
  508.      *
  509.      * @param count the length of random string to create
  510.      * @return the random string
  511.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  512.      * @since 3.5
  513.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  514.      */
  515.     @Deprecated
  516.     public static String randomGraph(final int count) {
  517.         return secure().nextGraph(count);
  518.     }

  520.     /**
  521.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  522.      *
  523.      * <p>
  524.      * Characters will be chosen from the set of \p{Graph} characters.
  525.      * </p>
  526.      *
  527.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  528.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  529.      * @return the random string
  530.      * @since 3.5
  531.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  532.      */
  533.     @Deprecated
  534.     public static String randomGraph(final int minLengthInclusive, final int maxLengthExclusive) {
  535.         return secure().nextGraph(minLengthInclusive, maxLengthExclusive);
  536.     }

  538.     /**
  539.      * Creates a random string whose length is the number of characters specified.
  540.      *
  541.      * <p>
  542.      * Characters will be chosen from the set of numeric characters.
  543.      * </p>
  544.      *
  545.      * @param count the length of random string to create
  546.      * @return the random string
  547.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  548.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  549.      */
  550.     @Deprecated
  551.     public static String randomNumeric(final int count) {
  552.         return secure().nextNumeric(count);
  553.     }

  555.     /**
  556.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  557.      *
  558.      * <p>
  559.      * Characters will be chosen from the set of \p{Digit} characters.
  560.      * </p>
  561.      *
  562.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  563.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  564.      * @return the random string
  565.      * @since 3.5
  566.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  567.      */
  568.     @Deprecated
  569.     public static String randomNumeric(final int minLengthInclusive, final int maxLengthExclusive) {
  570.         return secure().nextNumeric(minLengthInclusive, maxLengthExclusive);
  571.     }

  573.     /**
  574.      * Creates a random string whose length is the number of characters specified.
  575.      *
  576.      * <p>
  577.      * Characters will be chosen from the set of characters which match the POSIX [:print:] regular expression character
  578.      * class. This class includes all visible ASCII characters and spaces (i.e. anything except control characters).
  579.      * </p>
  580.      *
  581.      * @param count the length of random string to create
  582.      * @return the random string
  583.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  584.      * @since 3.5
  585.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  586.      */
  587.     @Deprecated
  588.     public static String randomPrint(final int count) {
  589.         return secure().nextPrint(count);
  590.     }

  592.     /**
  593.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  594.      *
  595.      * <p>
  596.      * Characters will be chosen from the set of \p{Print} characters.
  597.      * </p>
  598.      *
  599.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  600.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  601.      * @return the random string
  602.      * @since 3.5
  603.      * @deprecated Use {@link #secure()}, {@link #secureStrong()},or {@link #insecure()}.
  604.      */
  605.     @Deprecated
  606.     public static String randomPrint(final int minLengthInclusive, final int maxLengthExclusive) {
  607.         return secure().nextPrint(minLengthInclusive, maxLengthExclusive);
  608.     }

  610.     /**
  611.      * Gets the singleton instance based on {@link SecureRandom#SecureRandom()} which uses a secure random number generator (RNG) implementing the default
  612.      * random number algorithm.
  613.      * <p>
  614.      * The method {@link SecureRandom#SecureRandom()} is called on-demand.
  615.      * </p>
  616.      *
  617.      * @return the singleton instance based on {@link SecureRandom#SecureRandom()}.
  618.      * @see SecureRandom#SecureRandom()
  619.      * @since 3.16.0
  620.      */
  621.     public static RandomStringUtils secure() {
  622.         return SECURE;
  623.     }

  625.     /**
  626.      * Gets the singleton instance based on {@link SecureRandom#getInstanceStrong()} which uses an algorithms/providers
  627.      * specified in the {@code securerandom.strongAlgorithms} {@link Security} property.
  628.      * <p>
  629.      * The method {@link SecureRandom#getInstanceStrong()} is called on-demand.
  630.      * </p>
  631.      *
  632.      * @return the singleton instance based on {@link SecureRandom#getInstanceStrong()}.
  633.      * @see SecureRandom#getInstanceStrong()
  634.      * @since 3.17.0
  635.      */
  636.     public static RandomStringUtils secureStrong() {
  637.         return SECURE_STRONG;
  638.     }

  640.     private final Supplier<RandomUtils> random;

  642.     /**
  643.      * {@link RandomStringUtils} instances should NOT be constructed in standard programming. Instead, the class should
  644.      * be used as {@code RandomStringUtils.random(5);}.
  645.      *
  646.      * <p>
  647.      * This constructor is public to permit tools that require a JavaBean instance to operate.
  648.      * </p>
  649.      *
  650.      * @deprecated TODO Make private in 4.0.
  651.      */
  652.     @Deprecated
  653.     public RandomStringUtils() {
  654.         this(SECURE_SUPPLIER);
  655.     }

  657.     private RandomStringUtils(final Supplier<RandomUtils> random) {
  658.         this.random = random;
  659.     }

  661.     /**
  662.      * Creates a random string whose length is the number of characters specified.
  663.      *
  664.      * <p>
  665.      * Characters will be chosen from the set of all characters.
  666.      * </p>
  667.      *
  668.      * @param count the length of random string to create
  669.      * @return the random string
  670.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  671.      * @since 3.16.0
  672.      */
  673.     public String next(final int count) {
  674.         return next(count, false, false);
  675.     }

  677.     /**
  678.      * Creates a random string whose length is the number of characters specified.
  679.      *
  680.      * <p>
  681.      * Characters will be chosen from the set of alpha-numeric characters as indicated by the arguments.
  682.      * </p>
  683.      *
  684.      * @param count   the length of random string to create
  685.      * @param letters if {@code true}, generated string may include alphabetic characters
  686.      * @param numbers if {@code true}, generated string may include numeric characters
  687.      * @return the random string
  688.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  689.      * @since 3.16.0
  690.      */
  691.     public String next(final int count, final boolean letters, final boolean numbers) {
  692.         return next(count, 0, 0, letters, numbers);
  693.     }

  695.     /**
  696.      * Creates a random string whose length is the number of characters specified.
  697.      *
  698.      * <p>
  699.      * Characters will be chosen from the set of characters specified.
  700.      * </p>
  701.      *
  702.      * @param count the length of random string to create
  703.      * @param chars the character array containing the set of characters to use, may be null
  704.      * @return the random string
  705.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  706.      * @since 3.16.0
  707.      */
  708.     public String next(final int count, final char... chars) {
  709.         if (chars == null) {
  710.             return random(count, 0, 0, false, false, null, random());
  711.         }
  712.         return random(count, 0, chars.length, false, false, chars, random());
  713.     }

  715.     /**
  716.      * Creates a random string whose length is the number of characters specified.
  717.      *
  718.      * <p>
  719.      * Characters will be chosen from the set of alpha-numeric characters as indicated by the arguments.
  720.      * </p>
  721.      *
  722.      * @param count   the length of random string to create
  723.      * @param start   the position in set of chars to start at
  724.      * @param end     the position in set of chars to end before
  725.      * @param letters if {@code true}, generated string may include alphabetic characters
  726.      * @param numbers if {@code true}, generated string may include numeric characters
  727.      * @return the random string
  728.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  729.      * @since 3.16.0
  730.      */
  731.     public String next(final int count, final int start, final int end, final boolean letters, final boolean numbers) {
  732.         return random(count, start, end, letters, numbers, null, random());
  733.     }

  735.     /**
  736.      * Creates a random string based on a variety of options, using default source of randomness.
  737.      *
  738.      * <p>
  739.      * This method has exactly the same semantics as {@link #random(int,int,int,boolean,boolean,char[],Random)}, but
  740.      * instead of using an externally supplied source of randomness, it uses the internal static {@link Random}
  741.      * instance.
  742.      * </p>
  743.      *
  744.      * @param count   the length of random string to create
  745.      * @param start   the position in set of chars to start at
  746.      * @param end     the position in set of chars to end before
  747.      * @param letters if {@code true}, generated string may include alphabetic characters
  748.      * @param numbers if {@code true}, generated string may include numeric characters
  749.      * @param chars   the set of chars to choose randoms from. If {@code null}, then it will use the set of all chars.
  750.      * @return the random string
  751.      * @throws ArrayIndexOutOfBoundsException if there are not {@code (end - start) + 1} characters in the set array.
  752.      * @throws IllegalArgumentException       if {@code count} &lt; 0.
  753.      */
  754.     public String next(final int count, final int start, final int end, final boolean letters, final boolean numbers,
  755.             final char... chars) {
  756.         return random(count, start, end, letters, numbers, chars, random());
  757.     }

  759.     /**
  760.      * Creates a random string whose length is the number of characters specified.
  761.      *
  762.      * <p>
  763.      * Characters will be chosen from the set of characters specified by the string, must not be empty. If null, the set
  764.      * of all characters is used.
  765.      * </p>
  766.      *
  767.      * @param count the length of random string to create
  768.      * @param chars the String containing the set of characters to use, may be null, but must not be empty
  769.      * @return the random string
  770.      * @throws IllegalArgumentException if {@code count} &lt; 0 or the string is empty.
  771.      * @since 3.16.0
  772.      */
  773.     public String next(final int count, final String chars) {
  774.         if (chars == null) {
  775.             return random(count, 0, 0, false, false, null, random());
  776.         }
  777.         return next(count, chars.toCharArray());
  778.     }

  780.     /**
  781.      * Creates a random string whose length is the number of characters specified.
  782.      *
  783.      * <p>
  784.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z).
  785.      * </p>
  786.      *
  787.      * @param count the length of random string to create
  788.      * @return the random string
  789.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  790.      */
  791.     public String nextAlphabetic(final int count) {
  792.         return next(count, true, false);
  793.     }

  795.     /**
  796.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  797.      *
  798.      * <p>
  799.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z).
  800.      * </p>
  801.      *
  802.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  803.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  804.      * @return the random string
  805.      * @since 3.5
  806.      */
  807.     public String nextAlphabetic(final int minLengthInclusive, final int maxLengthExclusive) {
  808.         return nextAlphabetic(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  809.     }

  811.     /**
  812.      * Creates a random string whose length is the number of characters specified.
  813.      *
  814.      * <p>
  815.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z) and the digits 0-9.
  816.      * </p>
  817.      *
  818.      * @param count the length of random string to create
  819.      * @return the random string
  820.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  821.      */
  822.     public String nextAlphanumeric(final int count) {
  823.         return next(count, true, true);
  824.     }

  826.     /**
  827.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  828.      *
  829.      * <p>
  830.      * Characters will be chosen from the set of Latin alphabetic characters (a-z, A-Z) and the digits 0-9.
  831.      * </p>
  832.      *
  833.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  834.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  835.      * @return the random string
  836.      * @since 3.5
  837.      */
  838.     public String nextAlphanumeric(final int minLengthInclusive, final int maxLengthExclusive) {
  839.         return nextAlphanumeric(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  840.     }

  842.     /**
  843.      * Creates a random string whose length is the number of characters specified.
  844.      *
  845.      * <p>
  846.      * Characters will be chosen from the set of characters whose ASCII value is between {@code 32} and {@code 126}
  847.      * (inclusive).
  848.      * </p>
  849.      *
  850.      * @param count the length of random string to create
  851.      * @return the random string
  852.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  853.      */
  854.     public String nextAscii(final int count) {
  855.         return next(count, 32, 127, false, false);
  856.     }

  858.     /**
  859.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  860.      *
  861.      * <p>
  862.      * Characters will be chosen from the set of characters whose ASCII value is between {@code 32} and {@code 126}
  863.      * (inclusive).
  864.      * </p>
  865.      *
  866.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  867.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  868.      * @return the random string
  869.      * @since 3.5
  870.      */
  871.     public String nextAscii(final int minLengthInclusive, final int maxLengthExclusive) {
  872.         return nextAscii(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  873.     }

  875.     /**
  876.      * Creates a random string whose length is the number of characters specified.
  877.      *
  878.      * <p>
  879.      * Characters will be chosen from the set of characters which match the POSIX [:graph:] regular expression character
  880.      * class. This class contains all visible ASCII characters (i.e. anything except spaces and control characters).
  881.      * </p>
  882.      *
  883.      * @param count the length of random string to create
  884.      * @return the random string
  885.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  886.      * @since 3.5
  887.      */
  888.     public String nextGraph(final int count) {
  889.         return next(count, 33, 126, false, false);
  890.     }

  892.     /**
  893.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  894.      *
  895.      * <p>
  896.      * Characters will be chosen from the set of \p{Graph} characters.
  897.      * </p>
  898.      *
  899.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  900.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  901.      * @return the random string
  902.      * @since 3.5
  903.      */
  904.     public String nextGraph(final int minLengthInclusive, final int maxLengthExclusive) {
  905.         return nextGraph(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  906.     }

  908.     /**
  909.      * Creates a random string whose length is the number of characters specified.
  910.      *
  911.      * <p>
  912.      * Characters will be chosen from the set of numeric characters.
  913.      * </p>
  914.      *
  915.      * @param count the length of random string to create
  916.      * @return the random string
  917.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  918.      */
  919.     public String nextNumeric(final int count) {
  920.         return next(count, false, true);
  921.     }

  923.     /**
  924.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  925.      *
  926.      * <p>
  927.      * Characters will be chosen from the set of \p{Digit} characters.
  928.      * </p>
  929.      *
  930.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  931.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  932.      * @return the random string
  933.      * @since 3.5
  934.      */
  935.     public String nextNumeric(final int minLengthInclusive, final int maxLengthExclusive) {
  936.         return nextNumeric(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  937.     }

  939.     /**
  940.      * Creates a random string whose length is the number of characters specified.
  941.      *
  942.      * <p>
  943.      * Characters will be chosen from the set of characters which match the POSIX [:print:] regular expression character
  944.      * class. This class includes all visible ASCII characters and spaces (i.e. anything except control characters).
  945.      * </p>
  946.      *
  947.      * @param count the length of random string to create
  948.      * @return the random string
  949.      * @throws IllegalArgumentException if {@code count} &lt; 0.
  950.      * @since 3.5
  951.      * @since 3.16.0
  952.      */
  953.     public String nextPrint(final int count) {
  954.         return next(count, 32, 126, false, false);
  955.     }

  957.     /**
  958.      * Creates a random string whose length is between the inclusive minimum and the exclusive maximum.
  959.      *
  960.      * <p>
  961.      * Characters will be chosen from the set of \p{Print} characters.
  962.      * </p>
  963.      *
  964.      * @param minLengthInclusive the inclusive minimum length of the string to generate
  965.      * @param maxLengthExclusive the exclusive maximum length of the string to generate
  966.      * @return the random string
  967.      * @since 3.16.0
  968.      */
  969.     public String nextPrint(final int minLengthInclusive, final int maxLengthExclusive) {
  970.         return nextPrint(randomUtils().randomInt(minLengthInclusive, maxLengthExclusive));
  971.     }

  973.     /**
  974.      * Gets the Random.
  975.      *
  976.      * @return the Random.
  977.      */
  978.     private Random random() {
  979.         return randomUtils().random();
  980.     }

  982.     /**
  983.      * Gets the RandomUtils.
  984.      *
  985.      * @return the RandomUtils.
  986.      */
  987.     private RandomUtils randomUtils() {
  988.         return random.get();
  989.     }

  991.     @Override
  992.     public String toString() {
  993.         return "RandomStringUtils [random=" + random() + "]";
  994.     }

  996. }
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