src/main/java/org/apache/commons/lang3/RandomStringUtils.java - commons-lang - Git at Google

 /*
  * 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 {@code 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} &lt; 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} &lt; 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} &lt; 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>{@code 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() {
     }

 }
	/*
	* 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 {@code 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>{@code 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() {
	}

	}