| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2002-2003 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, if |
| * any, must include the following acknowlegement: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowlegement may appear in the software itself, |
| * if and wherever such third-party acknowlegements normally appear. |
| * |
| * 4. The names "The Jakarta Project", "Commons", and "Apache Software |
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| * 5. Products derived from this software may not be called "Apache" |
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| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.commons.lang; |
| |
| import java.util.Random; |
| /** |
| * <p>Common random <code>String</code> manipulation routines.</p> |
| * |
| * <p>Originally from the GenerationJava Core library.</p> |
| * |
| * @author <a href="mailto:bayard@generationjava.com">Henri Yandell</a> |
| * @author <a href="mailto:steven@caswell.name">Steven Caswell</a> |
| * @author Stephen Colebourne |
| * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a> |
| * @author Phil Steitz |
| * @since 1.0 |
| * @version $Id: RandomStringUtils.java,v 1.16 2003/07/16 00:39:05 scolebourne Exp $ |
| */ |
| public class RandomStringUtils { |
| |
| /** |
| * <p>Random object used by random method. This has to be not local |
| * to the random method so as to not return the same value in the |
| * same millisecond.</p> |
| */ |
| private static final Random RANDOM = new Random(); |
| |
| /** |
| * <p><code>RandomStringUtils</code> instances should NOT be constructed in |
| * standard programming. Instead, the class should be used as |
| * <code>RandomStringUtils.random(5);</code>.</p> |
| * |
| * <p>This constructor is public to permit tools that require a JavaBean instance |
| * to operate.</p> |
| */ |
| public RandomStringUtils() { |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of all characters.</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String random(int count) { |
| return random(count, false, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of characters whose |
| * ASCII value is between <code>32</code> and <code>126</code> (inclusive).</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAscii(int count) { |
| return random(count, 32, 127, false, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of alphabetic |
| * characters.</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAlphabetic(int count) { |
| return random(count, true, false); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of alpha-numeric |
| * characters.</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomAlphanumeric(int count) { |
| return random(count, true, true); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of numeric |
| * characters.</p> |
| * |
| * @param count the length of random string to create |
| * @return the random string |
| */ |
| public static String randomNumeric(int count) { |
| return random(count, false, true); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of alpha-numeric |
| * characters as indicated by the arguments.</p> |
| * |
| * @param count the length of random string to create |
| * @param letters if <code>true</code>, generated string will include |
| * alphabetic characters |
| * @param numbers if <code>true</code>, generatd string will include |
| * numeric characters |
| * @return the random string |
| */ |
| public static String random(int count, boolean letters, boolean numbers) { |
| return random(count, 0, 0, letters, numbers); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of alpha-numeric |
| * characters as indicated by the arguments.</p> |
| * |
| * @param count the length of random string to create |
| * @param start the position in set of chars to start at |
| * @param end the position in set of chars to end before |
| * @param letters if <code>true</code>, generated string will include |
| * alphabetic characters |
| * @param numbers if <code>true</code>, generated string will include |
| * numeric characters |
| * @return the random string |
| */ |
| public static String random(int count, int start, int end, boolean letters, boolean numbers) { |
| return random(count, start, end, letters, numbers, null); |
| } |
| |
| /** |
| * <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 ({@link #RANDOM}).</p> |
| * |
| * @param count the length of random string to create |
| * @param start the position in set of chars to start at |
| * @param end the position in set of chars to end before |
| * @param letters only allow letters? |
| * @param numbers only allow numbers? |
| * @param set the set of chars to choose randoms from. |
| * If <code>null</code>, then it will use the set of all chars. |
| * @return the random string |
| * @throws ArrayIndexOutOfBoundsException if there are not |
| * <code>(end - start) + 1</code> characters in the set array. |
| */ |
| public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] set) { |
| return random(count,start,end,letters,numbers,set,RANDOM); |
| } |
| |
| /** |
| * <p>Creates a random string based on a variety of options, using |
| * supplied source of randomness.</p> |
| * |
| * <p>If start and end are both <code>0</code>, start and end are set |
| * to <code>' '</code> and <code>'z'</code>, the ASCII printable |
| * characters, will be used, unless letters and numbers are both |
| * <code>false</code>, in which case, start and end are set to |
| * <code>0</code> and <code>Integer.MAX_VALUE</code>. |
| * |
| * <p>If set is not <code>null</code>, characters between start and |
| * end are chosen.</p> |
| * |
| * <p>As a source of randomness is used supplied {@link Random} |
| * instance. This makes method behave predictively, and allows |
| * usage of <code>RandomStringUtils</code> in situations that need |
| * repetitive behaviour.</p> |
| * |
| * @param count the length of random string to create |
| * @param start the position in set of chars to start at |
| * @param end the position in set of chars to end before |
| * @param letters only allow letters? |
| * @param numbers only allow numbers? |
| * @param set the set of chars to choose randoms from. |
| * If <code>null</code>, then it will use the set of all chars. |
| * @param random a source of randomness. |
| * @return the random string |
| * @throws ArrayIndexOutOfBoundsException if there are not |
| * <code>(end - start) + 1</code> characters in the set array. |
| * @throws IllegalArgumentException if <code>count</code> < 0. |
| */ |
| public static String random(int count, int start, int end, boolean letters, boolean numbers, char[] set, Random random) { |
| if( count == 0 ) { |
| return ""; |
| } else if( count < 0 ) { |
| throw new IllegalArgumentException("Requested random string length " + count + " is less than 0."); |
| } |
| if( (start == 0) && (end == 0) ) { |
| end = (int)'z' + 1; |
| start = (int)' '; |
| if(!letters && !numbers) { |
| start = 0; |
| end = Integer.MAX_VALUE; |
| } |
| } |
| |
| StringBuffer buffer = new StringBuffer(); |
| int gap = end - start; |
| |
| while(count-- != 0) { |
| char ch; |
| if(set == null) { |
| ch = (char)(random.nextInt(gap) + start); |
| } else { |
| ch = set[random.nextInt(gap) + start]; |
| } |
| if( (letters && numbers && Character.isLetterOrDigit(ch)) || |
| (letters && Character.isLetter(ch)) || |
| (numbers && Character.isDigit(ch)) || |
| (!letters && !numbers) |
| ) |
| { |
| buffer.append( ch ); |
| } else { |
| count++; |
| } |
| } |
| return buffer.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.</p> |
| * |
| * @param count the length of random string to create |
| * @param set the String containing the set of characters to use, |
| * must not be <code>null</code> |
| * @return the random string |
| * @throws NullPointerException if the set is <code>null</code> |
| */ |
| public static String random(int count, String set) { |
| return random(count, set.toCharArray()); |
| } |
| |
| /** |
| * <p>Creates a random string whose length is the number of characters |
| * specified.</p> |
| * |
| * <p>Characters will be chosen from the set of characters specified.</p> |
| * |
| * @param count the length of random string to create |
| * @param set the character array containing the set of characters to use |
| * must not be <code>null</code> |
| * @return the random string |
| * @throws NullPointerException if the set is <code>null</code> |
| */ |
| public static String random(int count, char[] set) { |
| return random(count, 0, set.length, false, false, set); |
| } |
| } |
