1   /**
2    * Copyright (c) 2000-2009 Liferay, Inc. All rights reserved.
3    *
4    * Permission is hereby granted, free of charge, to any person obtaining a copy
5    * of this software and associated documentation files (the "Software"), to deal
6    * in the Software without restriction, including without limitation the rights
7    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8    * copies of the Software, and to permit persons to whom the Software is
9    * furnished to do so, subject to the following conditions:
10   *
11   * The above copyright notice and this permission notice shall be included in
12   * all copies or substantial portions of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.portlet.words.util;
24  
25  import com.liferay.portlet.words.ScramblerException;
26  import com.liferay.portlet.words.util.comparator.WordComparator;
27  
28  import java.util.Set;
29  import java.util.TreeSet;
30  
31  /**
32   * <a href="Scrambler.java.html"><b><i>View Source</i></b></a>
33   *
34   * @author Brian Wing Shun Chan
35   *
36   */
37  public class Scrambler {
38  
39      public Scrambler(String word) throws ScramblerException {
40          if (word == null || word.length() < 3) {
41              throw new ScramblerException();
42          }
43  
44          _word = word;
45          _words = new TreeSet<String>(new WordComparator());
46      }
47  
48      public String[] scramble() {
49          if (_word == null) {
50              return new String[0];
51          }
52  
53          _scramble(0, _word.length(), _word.toCharArray());
54  
55          return _words.toArray(new String[_words.size()]);
56      }
57  
58      private void _rotate(char[] charArray, int start) {
59          char temp = charArray[start];
60  
61          for (int i = charArray.length - start -1; i > 0; i--) {
62              charArray[start] = charArray[++start];
63          }
64  
65          charArray[start] = temp;
66      }
67  
68      private void _scramble(int start, int length, char[] charArray) {
69          if (length == 0) {
70              String word = new String(charArray);
71  
72              for (int i = 3; i <= charArray.length; i++) {
73                  _words.add(word.substring(0, i));
74              }
75          }
76          else {
77              for (int i = 0; i < length; i++) {
78                  _scramble(start + 1, length - 1, charArray);
79                  _rotate(charArray, start);
80              }
81          }
82      }
83  
84      private String _word;
85      private Set<String> _words;
86  
87  }