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1   /* Copyright 2004 Acegi Technology Pty Limited
2    *
3    * Licensed under the Apache License, Version 2.0 (the "License");
4    * you may not use this file except in compliance with the License.
5    * You may obtain a copy of the License at
6    *
7    *     http://www.apache.org/licenses/LICENSE-2.0
8    *
9    * Unless required by applicable law or agreed to in writing, software
10   * distributed under the License is distributed on an "AS IS" BASIS,
11   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12   * See the License for the specific language governing permissions and
13   * limitations under the License.
14   */
15  
16  package org.acegisecurity.providers.encoding;
17  
18  /***
19   * <p>
20   * Convenience base for all password encoders.
21   * </p>
22   *
23   * @author Ben Alex
24   * @version $Id: BasePasswordEncoder.java,v 1.2 2005/11/17 00:55:49 benalex Exp $
25   */
26  public abstract class BasePasswordEncoder implements PasswordEncoder {
27      //~ Methods ================================================================
28  
29      /***
30       * Used by subclasses to extract the password and salt from a merged
31       * <code>String</code> created using {@link
32       * #mergePasswordAndSalt(String,Object,boolean)}.
33       * 
34       * <P>
35       * The first element in the returned array is the password. The second
36       * element is the salt. The salt array element will always be present,
37       * even if no salt was found in the <code>mergedPasswordSalt</code>
38       * argument.
39       * </p>
40       *
41       * @param mergedPasswordSalt as generated by
42       *        <code>mergePasswordAndSalt</code>
43       *
44       * @return an array, in which the first element is the password and the
45       *         second the salt
46       *
47       * @throws IllegalArgumentException DOCUMENT ME!
48       */
49      protected String[] demergePasswordAndSalt(String mergedPasswordSalt) {
50          if ((mergedPasswordSalt == null) || "".equals(mergedPasswordSalt)) {
51              throw new IllegalArgumentException(
52                  "Cannot pass a null or empty String");
53          }
54  
55          String password = mergedPasswordSalt;
56          String salt = "";
57  
58          int saltBegins = mergedPasswordSalt.lastIndexOf("{");
59  
60          if ((saltBegins != -1)
61              && ((saltBegins + 1) < mergedPasswordSalt.length())) {
62              salt = mergedPasswordSalt.substring(saltBegins + 1,
63                      mergedPasswordSalt.length() - 1);
64              password = mergedPasswordSalt.substring(0, saltBegins);
65          }
66  
67          return new String[] {password, salt};
68      }
69  
70      /***
71       * Used by subclasses to generate a merged password and salt
72       * <code>String</code>.
73       * 
74       * <P>
75       * The generated password will be in the form of
76       * <code>password{salt}</code>.
77       * </p>
78       * 
79       * <P>
80       * A <code>null</code> can be passed to either method, and will be handled
81       * correctly. If the <code>salt</code> is <code>null</code> or empty, the
82       * resulting generated password will simply be the passed
83       * <code>password</code>. The <code>toString</code> method of the
84       * <code>salt</code> will be used to represent the salt.
85       * </p>
86       *
87       * @param password the password to be used (can be <code>null</code>)
88       * @param salt the salt to be used (can be <code>null</code>)
89       * @param strict ensures salt doesn't contain the delimiters
90       *
91       * @return a merged password and salt <code>String</code>
92       *
93       * @throws IllegalArgumentException DOCUMENT ME!
94       */
95      protected String mergePasswordAndSalt(String password, Object salt,
96          boolean strict) {
97          if (password == null) {
98              password = "";
99          }
100 
101         if (strict && (salt != null)) {
102             if ((salt.toString().lastIndexOf("{") != -1)
103                 || (salt.toString().lastIndexOf("}") != -1)) {
104                 throw new IllegalArgumentException(
105                     "Cannot use { or } in salt.toString()");
106             }
107         }
108 
109         if ((salt == null) || "".equals(salt)) {
110             return password;
111         } else {
112             return password + "{" + salt.toString() + "}";
113         }
114     }
115 }