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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.dao;
    17
    18  import org.acegisecurity.userdetails.User;
    19  import org.acegisecurity.userdetails.UserDetails;
    20
    21
    22  /***
    23   * Provides a cache of {@link User} objects.
    24   *
    25   * <P>
    26   * Implementations should provide appropriate methods to set their cache
    27   * parameters (eg time-to-live) and/or force removal of entities before their
    28   * normal expiration. These are not part of the <code>UserCache</code>
    29   * interface contract because they vary depending on the type of caching
    30   * system used (eg in-memory vs disk vs cluster vs hybrid).
    31   * </p>
    32   *
    33   * @author Ben Alex
    34   * @version $Id: UserCache.java,v 1.6 2005/11/29 13:10:08 benalex Exp $
    35   */
    36  public interface UserCache {
    37      //~ Methods ================================================================
    38
    39      /***
    40       * Obtains a {@link UserDetails} from the cache.
    41       *
    42       * @param username the {@link User#getUsername()} used to place the user in
    43       *        the cache
    44       *
    45       * @return the populated <code>UserDetails</code> or <code>null</code> if
    46       *         the user could not be found or if the cache entry has expired
    47       */
    48      public UserDetails getUserFromCache(String username);
    49
    50      /***
    51       * Places a {@link UserDetails} in the cache. The <code>username</code> is
    52       * the key used to subsequently retrieve the <code>UserDetails</code>.
    53       *
    54       * @param user the fully populated <code>UserDetails</code> to place in the
    55       *        cache
    56       */
    57      public void putUserInCache(UserDetails user);
    58
    59      /***
    60       * Removes the specified user from the cache. The <code>username</code> is
    61       * the key used to remove the user. If the user is not found, the method
    62       * should simply return (not thrown an exception).
    63       *
    64       * <P>
    65       * Some cache implementations may not support eviction from the cache,  in
    66       * which case they should provide appropriate behaviour to alter the user
    67       * in either its documentation, via an exception, or through a log
    68       * message.
    69       * </p>
    70       *
    71       * @param username to be evicted from the cache
    72       */
    73      public void removeUserFromCache(String username);
    74  }