Coverage Report - org.apache.commons.lang3.RandomStringUtils
 
Classes in this File Line Coverage Branch Coverage Complexity
RandomStringUtils
96%
55/57
96%
54/56
3,833
 
 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  1
     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  1
       super();
 54  1
     }
 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  5
         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  102
         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  103
         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  101
         return random(count, true, true);
 111  
     }
 112  
     
 113  
     /**
 114  
      * <p>Creates a random string whose length is the number of characters
 115  
      * specified.</p>
 116  
      *
 117  
      * <p>Characters will be chosen from the set of numeric
 118  
      * characters.</p>
 119  
      *
 120  
      * @param count  the length of random string to create
 121  
      * @return the random string
 122  
      */
 123  
     public static String randomNumeric(final int count) {
 124  102
         return random(count, false, true);
 125  
     }
 126  
 
 127  
     /**
 128  
      * <p>Creates a random string whose length is the number of characters
 129  
      * specified.</p>
 130  
      *
 131  
      * <p>Characters will be chosen from the set of alpha-numeric
 132  
      * characters as indicated by the arguments.</p>
 133  
      *
 134  
      * @param count  the length of random string to create
 135  
      * @param letters  if {@code true}, generated string may include
 136  
      *  alphabetic characters
 137  
      * @param numbers  if {@code true}, generated string may include
 138  
      *  numeric characters
 139  
      * @return the random string
 140  
      */
 141  
     public static String random(final int count, final boolean letters, final boolean numbers) {
 142  312
         return random(count, 0, 0, letters, numbers);
 143  
     }
 144  
     
 145  
     /**
 146  
      * <p>Creates a random string whose length is the number of characters
 147  
      * specified.</p>
 148  
      *
 149  
      * <p>Characters will be chosen from the set of alpha-numeric
 150  
      * characters as indicated by the arguments.</p>
 151  
      *
 152  
      * @param count  the length of random string to create
 153  
      * @param start  the position in set of chars to start at
 154  
      * @param end  the position in set of chars to end before
 155  
      * @param letters  if {@code true}, generated string may include
 156  
      *  alphabetic characters
 157  
      * @param numbers  if {@code true}, generated string may include
 158  
      *  numeric characters
 159  
      * @return the random string
 160  
      */
 161  
     public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers) {
 162  416
         return random(count, start, end, letters, numbers, null, RANDOM);
 163  
     }
 164  
 
 165  
     /**
 166  
      * <p>Creates a random string based on a variety of options, using
 167  
      * default source of randomness.</p>
 168  
      *
 169  
      * <p>This method has exactly the same semantics as
 170  
      * {@link #random(int,int,int,boolean,boolean,char[],Random)}, but
 171  
      * instead of using an externally supplied source of randomness, it uses
 172  
      * the internal static {@link Random} instance.</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  only allow letters?
 178  
      * @param numbers  only allow numbers?
 179  
      * @param chars  the set of chars to choose randoms from.
 180  
      *  If {@code null}, then it will use the set of all chars.
 181  
      * @return the random string
 182  
      * @throws ArrayIndexOutOfBoundsException if there are not
 183  
      *  {@code (end - start) + 1} characters in the set array.
 184  
      */
 185  
     public static String random(final int count, final int start, final int end, final boolean letters, final boolean numbers, final char... chars) {
 186  1
         return random(count, start, end, letters, numbers, chars, RANDOM);
 187  
     }
 188  
 
 189  
     /**
 190  
      * <p>Creates a random string based on a variety of options, using
 191  
      * supplied source of randomness.</p>
 192  
      *
 193  
      * <p>If start and end are both {@code 0}, start and end are set
 194  
      * to {@code ' '} and {@code 'z'}, the ASCII printable
 195  
      * characters, will be used, unless letters and numbers are both
 196  
      * {@code false}, in which case, start and end are set to
 197  
      * {@code 0} and {@code Integer.MAX_VALUE}.
 198  
      *
 199  
      * <p>If set is not {@code null}, characters between start and
 200  
      * end are chosen.</p>
 201  
      *
 202  
      * <p>This method accepts a user-supplied {@link Random}
 203  
      * instance to use as a source of randomness. By seeding a single 
 204  
      * {@link Random} instance with a fixed seed and using it for each call,
 205  
      * the same random sequence of strings can be generated repeatedly
 206  
      * and predictably.</p>
 207  
      *
 208  
      * @param count  the length of random string to create
 209  
      * @param start  the position in set of chars to start at
 210  
      * @param end  the position in set of chars to end before
 211  
      * @param letters  only allow letters?
 212  
      * @param numbers  only allow numbers?
 213  
      * @param chars  the set of chars to choose randoms from, must not be empty.
 214  
      *  If {@code null}, then it will use the set of all chars.
 215  
      * @param random  a source of randomness.
 216  
      * @return the random string
 217  
      * @throws ArrayIndexOutOfBoundsException if there are not
 218  
      *  {@code (end - start) + 1} characters in the set array.
 219  
      * @throws IllegalArgumentException if {@code count} &lt; 0 or the provided chars array is empty.
 220  
      * @since 2.0
 221  
      */
 222  
     public static String random(int count, int start, int end, final boolean letters, final boolean numbers,
 223  
                                 final char[] chars, final Random random) {
 224  533
         if (count == 0) {
 225  1
             return "";
 226  532
         } else if (count < 0) {
 227  8
             throw new IllegalArgumentException("Requested random string length " + count + " is less than 0.");
 228  
         }
 229  524
         if (chars != null && chars.length == 0) {
 230  1
             throw new IllegalArgumentException("The chars array must not be empty");
 231  
         }
 232  
 
 233  523
         if (start == 0 && end == 0) {
 234  316
             if (chars != null) {
 235  1
                 end = chars.length;
 236  
             } else {
 237  315
                 if (!letters && !numbers) {
 238  7
                     end = Integer.MAX_VALUE;
 239  
                 } else {
 240  308
                     end = 'z' + 1;
 241  308
                     start = ' ';                
 242  
                 }
 243  
             }
 244  
         } else {
 245  207
             if (end <= start) {
 246  1
                 throw new IllegalArgumentException("Parameter end (" + end + ") must be greater than start (" + start + ")");
 247  
             }
 248  
         }
 249  
 
 250  522
         final char[] buffer = new char[count];
 251  522
         final int gap = end - start;
 252  
 
 253  21391
         while (count-- != 0) {
 254  
             char ch;
 255  20869
             if (chars == null) {
 256  20066
                 ch = (char) (random.nextInt(gap) + start);
 257  
             } else {
 258  803
                 ch = chars[random.nextInt(gap) + start];
 259  
             }
 260  20869
             if (letters && Character.isLetter(ch)
 261  
                     || numbers && Character.isDigit(ch)
 262  
                     || !letters && !numbers) {
 263  10446
                 if(ch >= 56320 && ch <= 57343) {
 264  88
                     if(count == 0) {
 265  0
                         count++;
 266  
                     } else {
 267  
                         // low surrogate, insert high surrogate after putting it in
 268  88
                         buffer[count] = ch;
 269  88
                         count--;
 270  88
                         buffer[count] = (char) (55296 + random.nextInt(128));
 271  
                     }
 272  10358
                 } else if(ch >= 55296 && ch <= 56191) {
 273  81
                     if(count == 0) {
 274  0
                         count++;
 275  
                     } else {
 276  
                         // high surrogate, insert low surrogate before putting it in
 277  81
                         buffer[count] = (char) (56320 + random.nextInt(128));
 278  81
                         count--;
 279  81
                         buffer[count] = ch;
 280  
                     }
 281  10277
                 } else if(ch >= 56192 && ch <= 56319) {
 282  
                     // private high surrogate, no effing clue, so skip it
 283  12
                     count++;
 284  
                 } else {
 285  10265
                     buffer[count] = ch;
 286  
                 }
 287  
             } else {
 288  10423
                 count++;
 289  
             }
 290  20869
         }
 291  522
         return new String(buffer);
 292  
     }
 293  
 
 294  
     /**
 295  
      * <p>Creates a random string whose length is the number of characters
 296  
      * specified.</p>
 297  
      *
 298  
      * <p>Characters will be chosen from the set of characters
 299  
      * specified by the string, must not be empty. 
 300  
      * If null, the set of all characters is used.</p>
 301  
      *
 302  
      * @param count  the length of random string to create
 303  
      * @param chars  the String containing the set of characters to use,
 304  
      *  may be null, but must not be empty
 305  
      * @return the random string
 306  
      * @throws IllegalArgumentException if {@code count} &lt; 0 or the string is empty.
 307  
      */
 308  
     public static String random(final int count, final String chars) {
 309  7
         if (chars == null) {
 310  3
             return random(count, 0, 0, false, false, null, RANDOM);
 311  
         }
 312  4
         return random(count, chars.toCharArray());
 313  
     }
 314  
 
 315  
     /**
 316  
      * <p>Creates a random string whose length is the number of characters
 317  
      * specified.</p>
 318  
      *
 319  
      * <p>Characters will be chosen from the set of characters specified.</p>
 320  
      *
 321  
      * @param count  the length of random string to create
 322  
      * @param chars  the character array containing the set of characters to use,
 323  
      *  may be null
 324  
      * @return the random string
 325  
      * @throws IllegalArgumentException if {@code count} &lt; 0.
 326  
      */
 327  
     public static String random(final int count, final char... chars) {
 328  109
         if (chars == null) {
 329  2
             return random(count, 0, 0, false, false, null, RANDOM);
 330  
         }
 331  107
         return random(count, 0, chars.length, false, false, chars, RANDOM);
 332  
     }
 333  
     
 334  
 }