Coverage Report - org.apache.commons.lang3.RandomStringUtils
 
Classes in this File Line Coverage Branch Coverage Complexity
RandomStringUtils
96%
57/59
96%
54/56
3,429
 
 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;
 18  
 
 19  
 import java.util.Random;
 20  
 
 21  
 /**
 22  
  * <p>Operations for random {@code String}s.</p>
 23  
  * <p>Currently <em>private high surrogate</em> characters are ignored. 
 24  
  * These are Unicode characters that fall between the values 56192 (db80)
 25  
  * and 56319 (dbff) as we don't know how to handle them. 
 26  
  * High and low surrogates are correctly dealt with - that is if a 
 27  
  * high surrogate is randomly chosen, 55296 (d800) to 56191 (db7f) 
 28  
  * then it is followed by a low surrogate. If a low surrogate is chosen, 
 29  
  * 56320 (dc00) to 57343 (dfff) then it is placed after a randomly 
 30  
  * chosen high surrogate. </p>
 31  
  *
 32  
  * <p>#ThreadSafe#</p>
 33  
  * @since 1.0
 34  
  */
 35  
 public class RandomStringUtils {
 36  
 
 37  
     /**
 38  
      * <p>Random object used by random method. This has to be not local
 39  
      * to the random method so as to not return the same value in the 
 40  
      * same millisecond.</p>
 41  
      */
 42  2
     private static final Random RANDOM = new Random();
 43  
 
 44  
     /**
 45  
      * <p>{@code RandomStringUtils} instances should NOT be constructed in
 46  
      * standard programming. Instead, the class should be used as
 47  
      * {@code RandomStringUtils.random(5);}.</p>
 48  
      *
 49  
      * <p>This constructor is public to permit tools that require a JavaBean instance
 50  
      * to operate.</p>
 51  
      */
 52  
     public RandomStringUtils() {
 53  2
       super();
 54  2
     }
 55  
 
 56  
     // Random
 57  
     //-----------------------------------------------------------------------
 58  
     /**
 59  
      * <p>Creates a random string whose length is the number of characters
 60  
      * specified.</p>
 61  
      *
 62  
      * <p>Characters will be chosen from the set of all characters.</p>
 63  
      *
 64  
      * @param count  the length of random string to create
 65  
      * @return the random string
 66  
      */
 67  
     public static String random(final int count) {
 68  10
         return random(count, false, false);
 69  
     }
 70  
 
 71  
     /**
 72  
      * <p>Creates a random string whose length is the number of characters
 73  
      * specified.</p>
 74  
      *
 75  
      * <p>Characters will be chosen from the set of characters whose
 76  
      * ASCII value is between {@code 32} and {@code 126} (inclusive).</p>
 77  
      *
 78  
      * @param count  the length of random string to create
 79  
      * @return the random string
 80  
      */
 81  
     public static String randomAscii(final int count) {
 82  204
         return random(count, 32, 127, false, false);
 83  
     }
 84  
     
 85  
     /**
 86  
      * <p>Creates a random string whose length is the number of characters
 87  
      * specified.</p>
 88  
      *
 89  
      * <p>Characters will be chosen from the set of alphabetic
 90  
      * characters.</p>
 91  
      *
 92  
      * @param count  the length of random string to create
 93  
      * @return the random string
 94  
      */
 95  
     public static String randomAlphabetic(final int count) {
 96  206
         return random(count, true, false);
 97  
     }
 98  
     
 99  
     /**
 100  
      * <p>Creates a random string whose length is the number of characters
 101  
      * specified.</p>
 102  
      *
 103  
      * <p>Characters will be chosen from the set of alpha-numeric
 104  
      * characters.</p>
 105  
      *
 106  
      * @param count  the length of random string to create
 107  
      * @return the random string
 108  
      */
 109  
     public static String randomAlphanumeric(final int count) {
 110  202
         return random(count, true, true);
 111  
     }
 112  
     
 113  
     /**
 114  
      * <p>Creates a random string whose length is the number of characters specified.</p>
 115  
      *
 116  
      * <p>Characters will be chosen from the set of characters which match the POSIX [:graph:]
 117  
      * regular expression character class. This class contains all visible ASCII characters 
 118  
      * (i.e. anything except spaces and control characters).</p>
 119  
      *
 120  
      * @param count  the length of random string to create
 121  
      * @return the random string
 122  
      * @since 3.5
 123  
      */
 124  
     public static String randomGraph(final int count) {
 125  4
         return random(count, 33, 126, false, false);
 126  
     }
 127  
     
 128  
     /**
 129  
      * <p>Creates a random string whose length is the number of characters
 130  
      * specified.</p>
 131  
      *
 132  
      * <p>Characters will be chosen from the set of numeric
 133  
      * characters.</p>
 134  
      *
 135  
      * @param count  the length of random string to create
 136  
      * @return the random string
 137  
      */
 138  
     public static String randomNumeric(final int count) {
 139  204
         return random(count, false, true);
 140  
     }
 141  
 
 142  
     /**
 143  
      * <p>Creates a random string whose length is the number of characters specified.</p>
 144  
      *
 145  
      * <p>Characters will be chosen from the set of characters which match the POSIX [:print:]
 146  
      * regular expression character class. This class includes all visible ASCII characters and spaces
 147  
      * (i.e. anything except control characters).</p>
 148  
      *
 149  
      * @param count  the length of random string to create
 150  
      * @return the random string
 151  
      * @since 3.5
 152  
      */
 153  
     public static String randomPrint(final int count) {
 154  4
         return random(count, 32, 126, false, false);
 155  
     }
 156  
 
 157  
     /**
 158  
      * <p>Creates a random string whose length is the number of characters
 159  
      * specified.</p>
 160  
      *
 161  
      * <p>Characters will be chosen from the set of alpha-numeric
 162  
      * characters as indicated by the arguments.</p>
 163  
      *
 164  
      * @param count  the length of random string to create
 165  
      * @param letters  if {@code true}, generated string may include
 166  
      *  alphabetic characters
 167  
      * @param numbers  if {@code true}, generated string may include
 168  
      *  numeric characters
 169  
      * @return the random string
 170  
      */
 171  
     public static String random(final int count, final boolean letters, final boolean numbers) {
 172  624
         return random(count, 0, 0, letters, numbers);
 173  
     }
 174  
     
 175  
     /**
 176  
      * <p>Creates a random string whose length is the number of characters
 177  
      * specified.</p>
 178  
      *
 179  
      * <p>Characters will be chosen from the set of alpha-numeric
 180  
      * characters as indicated by the arguments.</p>
 181  
      *
 182  
      * @param count  the length of random string to create
 183  
      * @param start  the position in set of chars to start at
 184  
      * @param end  the position in set of chars to end before
 185  
      * @param letters  if {@code true}, generated string may include
 186  
      *  alphabetic characters
 187  
      * @param numbers  if {@code true}, generated string may include
 188  
      *  numeric characters
 189  
      * @return the random string
 190  
      */
 191  
     public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers) {
 192  840
         return random(count, start, end, letters, numbers, null, RANDOM);
 193  
     }
 194  
 
 195  
     /**
 196  
      * <p>Creates a random string based on a variety of options, using
 197  
      * default source of randomness.</p>
 198  
      *
 199  
      * <p>This method has exactly the same semantics as
 200  
      * {@link #random(int,int,int,boolean,boolean,char[],Random)}, but
 201  
      * instead of using an externally supplied source of randomness, it uses
 202  
      * the internal static {@link Random} instance.</p>
 203  
      *
 204  
      * @param count  the length of random string to create
 205  
      * @param start  the position in set of chars to start at
 206  
      * @param end  the position in set of chars to end before
 207  
      * @param letters  only allow letters?
 208  
      * @param numbers  only allow numbers?
 209  
      * @param chars  the set of chars to choose randoms from.
 210  
      *  If {@code null}, then it will use the set of all chars.
 211  
      * @return the random string
 212  
      * @throws ArrayIndexOutOfBoundsException if there are not
 213  
      *  {@code (end - start) + 1} characters in the set array.
 214  
      */
 215  
     public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers, final char... chars) {
 216  2
         return random(count, start, end, letters, numbers, chars, RANDOM);
 217  
     }
 218  
 
 219  
     /**
 220  
      * <p>Creates a random string based on a variety of options, using
 221  
      * supplied source of randomness.</p>
 222  
      *
 223  
      * <p>If start and end are both {@code 0}, start and end are set
 224  
      * to {@code ' '} and {@code 'z'}, the ASCII printable
 225  
      * characters, will be used, unless letters and numbers are both
 226  
      * {@code false}, in which case, start and end are set to
 227  
      * {@code 0} and {@code Integer.MAX_VALUE}.
 228  
      *
 229  
      * <p>If set is not {@code null}, characters between start and
 230  
      * end are chosen.</p>
 231  
      *
 232  
      * <p>This method accepts a user-supplied {@link Random}
 233  
      * instance to use as a source of randomness. By seeding a single 
 234  
      * {@link Random} instance with a fixed seed and using it for each call,
 235  
      * the same random sequence of strings can be generated repeatedly
 236  
      * and predictably.</p>
 237  
      *
 238  
      * @param count  the length of random string to create
 239  
      * @param start  the position in set of chars to start at
 240  
      * @param end  the position in set of chars to end before
 241  
      * @param letters  only allow letters?
 242  
      * @param numbers  only allow numbers?
 243  
      * @param chars  the set of chars to choose randoms from, must not be empty.
 244  
      *  If {@code null}, then it will use the set of all chars.
 245  
      * @param random  a source of randomness.
 246  
      * @return the random string
 247  
      * @throws ArrayIndexOutOfBoundsException if there are not
 248  
      *  {@code (end - start) + 1} characters in the set array.
 249  
      * @throws IllegalArgumentException if {@code count} &lt; 0 or the provided chars array is empty.
 250  
      * @since 2.0
 251  
      */
 252  
     public static String random(int count, int start, int end, final boolean letters, final boolean numbers,
 253  
                                 final char[] chars, final Random random) {
 254  1074
         if (count == 0) {
 255  2
             return StringUtils.EMPTY;
 256  1072
         } else if (count < 0) {
 257  16
             throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");
 258  
         }
 259  1056
         if (chars != null && chars.length == 0) {
 260  2
             throw new IllegalArgumentException("The chars array must not be empty");
 261  
         }
 262  
 
 263  1054
         if (start == 0 && end == 0) {
 264  632
             if (chars != null) {
 265  2
                 end = chars.length;
 266  
             } else {
 267  630
                 if (!letters && !numbers) {
 268  14
                     end = Integer.MAX_VALUE;
 269  
                 } else {
 270  616
                     end = 'z' + 1;
 271  616
                     start = ' ';                
 272  
                 }
 273  
             }
 274  
         } else {
 275  422
             if (end <= start) {
 276  2
                 throw new IllegalArgumentException("Parameter end (" + end + ") must be greater than start (" + start + ")");
 277  
             }
 278  
         }
 279  
 
 280  1052
         final char[] buffer = new char[count];
 281  1052
         final int gap = end - start;
 282  
 
 283  42313
         while (count-- != 0) {
 284  
             char ch;
 285  41261
             if (chars == null) {
 286  39655
                 ch = (char) (random.nextInt(gap) + start);
 287  
             } else {
 288  1606
                 ch = chars[random.nextInt(gap) + start];
 289  
             }
 290  41261
             if (letters && Character.isLetter(ch)
 291  
                     || numbers && Character.isDigit(ch)
 292  
                     || !letters && !numbers) {
 293  21349
                 if(ch >= 56320 && ch <= 57343) {
 294  147
                     if(count == 0) {
 295  0
                         count++;
 296  
                     } else {
 297  
                         // low surrogate, insert high surrogate after putting it in
 298  147
                         buffer[count] = ch;
 299  147
                         count--;
 300  147
                         buffer[count] = (char) (55296 + random.nextInt(128));
 301  
                     }
 302  21202
                 } else if(ch >= 55296 && ch <= 56191) {
 303  135
                     if(count == 0) {
 304  0
                         count++;
 305  
                     } else {
 306  
                         // high surrogate, insert low surrogate before putting it in
 307  135
                         buffer[count] = (char) (56320 + random.nextInt(128));
 308  135
                         count--;
 309  135
                         buffer[count] = ch;
 310  
                     }
 311  21067
                 } else if(ch >= 56192 && ch <= 56319) {
 312  
                     // private high surrogate, no effing clue, so skip it
 313  25
                     count++;
 314  
                 } else {
 315  21042
                     buffer[count] = ch;
 316  
                 }
 317  
             } else {
 318  19912
                 count++;
 319  
             }
 320  41261
         }
 321  1052
         return new String(buffer);
 322  
     }
 323  
 
 324  
     /**
 325  
      * <p>Creates a random string whose length is the number of characters
 326  
      * specified.</p>
 327  
      *
 328  
      * <p>Characters will be chosen from the set of characters
 329  
      * specified by the string, must not be empty. 
 330  
      * If null, the set of all characters is used.</p>
 331  
      *
 332  
      * @param count  the length of random string to create
 333  
      * @param chars  the String containing the set of characters to use,
 334  
      *  may be null, but must not be empty
 335  
      * @return the random string
 336  
      * @throws IllegalArgumentException if {@code count} &lt; 0 or the string is empty.
 337  
      */
 338  
     public static String random(final int count, final String chars) {
 339  14
         if (chars == null) {
 340  6
             return random(count, 0, 0, false, false, null, RANDOM);
 341  
         }
 342  8
         return random(count, chars.toCharArray());
 343  
     }
 344  
 
 345  
     /**
 346  
      * <p>Creates a random string whose length is the number of characters
 347  
      * specified.</p>
 348  
      *
 349  
      * <p>Characters will be chosen from the set of characters specified.</p>
 350  
      *
 351  
      * @param count  the length of random string to create
 352  
      * @param chars  the character array containing the set of characters to use,
 353  
      *  may be null
 354  
      * @return the random string
 355  
      * @throws IllegalArgumentException if {@code count} &lt; 0.
 356  
      */
 357  
     public static String random(final int count, final char... chars) {
 358  218
         if (chars == null) {
 359  4
             return random(count, 0, 0, false, false, null, RANDOM);
 360  
         }
 361  214
         return random(count, 0, chars.length, false, false, chars, RANDOM);
 362  
     }
 363  
     
 364  
 }