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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 }