RandomStrg


1   /*
2    * Copyright 1999,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.apache.taglibs.random;
18  
19  import java.security.NoSuchAlgorithmException  ;
20  import java.security.NoSuchProviderException  ;
21  import java.security.SecureRandom  ;
22  import java.util.ArrayList  ;
23  import java.util.HashMap  ;
24  import java.util.Random  ;
25  
26  import javax.servlet.jsp.JspException  ;
27  
28  /**
29   * RandomStrg class will produce a variable set of random characters.
30   *
31   * @author Rich Catlett
32   *
33   * @version 1.0
34   *
35   */
36  
37  public class RandomStrg {
38  
39      /**
40       * generated password
41       */
42      private String   randomstr;
43      /**
44       * flag determines if all chars ar to be used
45       */
46      private boolean allchars = false;
47      /**
48       * length of random string defaults to 8
49       */
50      private Integer   length = new Integer  (8);
51      /**
52       * list of all generated strings, list is stored at the application level
53       */
54      private HashMap   hmap;
55      /**
56       * ArrayList for the lowerbound of the char sets
57       */
58      private ArrayList   lower = null;
59      /**
60       * ArrayList for the upperbound of the char sets
61       */
62      private ArrayList   upper = null;
63      /**
64       * Array for the set of chars that aren't part of a range
65       */
66      private char[] single = null;
67      /**
68       * counter for position in the array single
69       */
70      private int singlecount = 0;
71      /**
72       * boolean flat that tells the random char generator if there is a list of
73       * single chars
74       */
75      private boolean singles = false;
76      /**
77       * the algorithm to use for a SecureRandom object
78       */
79      private String   algorithm = null;
80      /**
81       * the provider package to check for the algorithm
82       */
83      private String   provider = null;
84      /**
85       * boolean value that marks if a Random or SecureRandom object is to be used,
86       * default value of false says that a Random object will be used
87       */
88      private boolean secure = false;
89      /**
90       * random object that could be used
91       */
92      private Random   random = null;
93      /**
94       * SecureRandom object that could be used
95       */
96      private SecureRandom   secrandom = null;
97  
98      /**
99       * nethod determines if a Random or SecureRandom object is to be used to
100      * generate the random number
101      *
102      */
103     private final float getFloat() {
104     if (random == null)
105         return secrandom.nextFloat();
106     else
107         return random.nextFloat();
108     }
109 
110     /**
111      * generate the Random object that will be used for this random number 
112      * generator
113      *
114      */
115     public final void generateRandomObject() throws JspException   {
116 
117     // check to see if the object is a SecureRandom object
118     if (secure) {
119         try {
120         // get an instance of a SecureRandom object
121         if (provider != null)
122             // search for algorithm in package provider
123             random = SecureRandom.getInstance(algorithm, provider);
124         else
125             random = SecureRandom.getInstance(algorithm);
126         } catch (NoSuchAlgorithmException   ne) {
127         throw new JspException  (ne.getMessage());
128         } catch (NoSuchProviderException   pe) {
129         throw new JspException  (pe.getMessage());
130         }
131     } else
132         random = new Random  ();
133     }
134 
135     /**
136      * generate the random string
137      *
138      */
139     private final void generaterandom() {
140 
141     // use all chars in the string
142     if (allchars)
143         for (int i = 0; i < length.intValue(); i++)
144         randomstr = randomstr + new Character  ((char)((int) 34 + 
145                      ((int)(getFloat() * 93)))).toString();
146     else if (singles) {
147         // check if there are single chars to be included
148 
149         if (upper.size() == 3) {
150         // check for the number of ranges max 3 uppercase lowercase digits
151 
152         // build the random string
153         for (int i = 0; i < length.intValue(); i++) {
154             // you have four groups to choose a random number from, to make
155             // the choice a little more random select a number out of 100
156 
157             // get a random number even or odd
158             if (((int) (getFloat() * 100)) % 2 == 0) {
159 
160             // the number was even get another number even or odd
161             if (((int) (getFloat() * 100)) % 2 == 0)
162                 // choose a random char from the single char group
163                 randomstr = randomstr + randomSingle().toString();
164             else
165                 // get a random char from the first range
166                 randomstr = randomstr + randomChar((Character  )lower.get(2),
167                         (Character  )upper.get(2)).toString();
168             } else {
169             // the number was odd
170 
171             if (((int) (getFloat() * 100)) % 2 == 0)
172                 // choose a random char from the second range
173                 randomstr = randomstr + randomChar((Character  )lower.get(1),
174                            (Character  )upper.get(1)).toString();
175             else
176                 // choose a random char from the third range
177                 randomstr = randomstr + randomChar((Character  )lower.get(0),  
178                            (Character  )upper.get(0)).toString();
179             }
180         }
181         } else if (upper.size() == 2) {
182         // single chars are to be included choose a random char from
183         // two different ranges
184 
185         // build the random char from single chars and two ranges
186         for (int i = 0; i < length.intValue(); i++) {
187             // select the single chars or a range to get each random char
188             // from
189 
190             if (((int)(getFloat() * 100)) % 2 == 0) {
191 
192             // get random char from the single chars
193             randomstr = randomstr + randomSingle().toString();
194             } else if (((int) (getFloat() * 100)) % 2 == 0) {
195 
196             // get the random char from the first range
197             randomstr = randomstr + randomChar((Character  )lower.get(1),
198                            (Character  )upper.get(1)).toString();
199             } else {
200 
201             // get the random char from the second range
202             randomstr = randomstr + randomChar((Character  )lower.get(0),
203                            (Character  )upper.get(0)).toString();
204             }
205         }
206         } else if (upper.size() == 1) {
207 
208         // build the random string from single chars and one range
209         for (int i = 0; i < length.intValue(); i++) {
210             if (((int) getFloat() * 100) % 2 == 0)
211             // get a random single char
212             randomstr = randomstr + randomSingle().toString();
213             else
214             // get a random char from the range
215             randomstr = randomstr + randomChar((Character  )lower.get(0),
216                            (Character  )upper.get(0)).toString();
217         }
218         } else {
219         // build the rand string from single chars
220         for (int i = 0; i < length.intValue(); i++)
221             randomstr = randomstr + randomSingle().toString();
222         }
223     } else {
224 
225         // no single chars are to be included in the random string
226         if (upper.size() == 3) {
227 
228         // build random strng from three ranges
229         for (int i = 0; i < length.intValue(); i++) {
230 
231             if (((int) (getFloat() * 100)) % 2 == 0) {
232 
233             // get random char from first range
234             randomstr = randomstr + randomChar((Character  )lower.get(2),
235                            (Character  )upper.get(2)).toString();
236             } else if (((int) (getFloat() * 100)) % 2 == 0) {
237 
238             // get random char form second range
239             randomstr = randomstr + randomChar((Character  )lower.get(1),
240                            (Character  )upper.get(1)).toString();
241             } else {
242 
243             // get random char from third range
244             randomstr = randomstr + randomChar((Character  )lower.get(0),
245                            (Character  )upper.get(0)).toString();
246             }
247         }
248         } else if (upper.size() == 2) {
249 
250         // build random string from two ranges
251         for (int i = 0; i < length.intValue(); i++) {
252             if (((int) (getFloat() * 100)) % 2 == 0)
253             // get random char from first range
254             randomstr = randomstr + randomChar((Character  )lower.get(1),
255                            (Character  )upper.get(1)).toString();
256             else
257             // get random char from second range
258             randomstr = randomstr + randomChar((Character  )lower.get(0),
259                          (Character  )upper.get(0)).toString();
260         }
261         } else
262 
263         // build random string
264         for (int i = 0; i < length.intValue(); i++)
265             // get random char from only range
266             randomstr = randomstr + randomChar((Character  )lower.get(0), 
267                            (Character  )upper.get(0)).toString();
268     }
269     }
270 
271     /**
272      * generate a random char from the single char list
273      *
274      * @returns - a randomly selscted character from the single char list
275      *
276      */
277     private final Character   randomSingle() {
278 
279     return (new Character  (single[(int)((getFloat() * singlecount) - 1)]));
280     }
281 
282     /**
283      * generate a random character
284      *
285      * @param lower  lower bound from which to get a random char
286      * @param upper  upper bound from which to get a random char
287      *
288      * @returns - a randomly generated character
289      *
290      */
291     private final Character   randomChar(Character   lower, Character   upper) {
292     int tempval;
293     char low = lower.charValue();
294     char up = upper.charValue();
295 
296     // get a random number in the range lowlow - lowup
297     tempval = (int)((int)low + (getFloat() * ((int)(up - low))));
298 
299     // return the random char
300     return (new Character  ((char) tempval));
301     }
302 
303     /**
304      * get the randomly created string for use with the 
305      * &lt;jsp:getProperty name=<i>"id"</i> property="randomstr"/&gt;
306      *
307      * @return - randomly created string
308      *
309      */
310     public final String   getRandom() {
311 
312     randomstr = new String  ();
313 
314     generaterandom(); // generate the first random string
315 
316     if (hmap != null) {
317 
318         while (hmap.containsKey(randomstr)) {
319         // random string has already been created generate a different one
320         generaterandom();
321         }
322 
323         hmap.put(randomstr, null);  // add the new random string
324     }
325 
326     return randomstr;
327     }
328 
329     /**
330      * set the ranges from which to choose the characters for the random string
331      *
332      * @param low  set of lower ranges
333      * @param up  set of upper ranges
334      *
335      */
336     public final void setRanges(ArrayList   low, ArrayList   up) {
337     lower = low;
338     upper = up;
339     }
340 
341 
342     /**
343      * set the hashmap that is used to check the uniqueness of random strings
344      *
345      * @param map  hashmap whose keys are used to insure uniqueness of random strgs
346      *
347      */
348     public final void setHmap(HashMap   map) {
349     hmap = map;
350     }
351 
352     /**
353      * set the length of the random string
354      *
355      * @param value  length of the random string
356      *
357      */
358     public final void setLength(Integer   value) {
359     length = value;
360     }
361 
362     /**
363      * set the algorithm name
364      *
365      * @param value  name of the algorithm to use for a SecureRandom object
366      *
367      */
368     public final void setAlgorithm(String   value) {
369     algorithm = value;
370     secure = true;  // a SecureRandom object is to be used
371     }
372 
373     /**
374      * set the provider name
375      *
376      * @param value  name of the package to check for the algorithm
377      *
378      */
379     public final void setProvider(String   value) {
380     provider = value;
381     }
382 
383     /**
384      * set the allchars flag
385      *
386      * @param value  boolean value of the allchars flag
387      *
388      */
389     public final void setAllchars(boolean value) {
390     allchars = value;
391     }
392 
393     /**
394      * set the array of single chars to choose from for this random string and the
395      * number of chars in the array
396      *
397      * @param chars  the array of single chars
398      * @param value  the number of single chars
399      *
400      */
401     public final void setSingle(char[] chars, int value) {
402     single = chars;  // set the array of chars
403     singlecount = value;  // set the number of chars in array single
404     singles = true;  // set flag that single chars are in use
405     }
406 }
407
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