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    1   /* Copyright 2004, 2005 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.captcha;
    17
    18  import org.springframework.util.Assert;
    19
    20
    21  /***
    22   * <p>
    23   * return false if thresold is lower than average time millis between any
    24   * CaptchaChannelProcessorTemplate mapped urls requests and is human;<br>
    25   * Default keyword : REQUIRES_CAPTCHA_AFTER_THRESOLD_IN_MILLIS <br>
    26   * Note : before first humanity check
    27   * </p>
    28   *
    29   * @author Marc-Antoine Garrigue
    30   * @version $Id: AlwaysTestBelowAverageTimeInMillisBetweenRequestsChannelProcessor.java,v 1.2 2005/11/17 00:55:49 benalex Exp $
    31   */
    32  public class AlwaysTestBelowAverageTimeInMillisBetweenRequestsChannelProcessor
    33      extends CaptchaChannelProcessorTemplate {
    34      //~ Static fields/initializers =============================================
    35
    36      /*** Keyword for this channelProcessor */
    37      public static final String DEFAULT_KEYWORD = "REQUIRES_CAPTCHA_BELOW_AVERAGE_TIME_IN_MILLIS_REQUESTS";
    38
    39      //~ Constructors ===========================================================
    40
    41      /***
    42       * Constructor
    43       */
    44      public AlwaysTestBelowAverageTimeInMillisBetweenRequestsChannelProcessor() {
    45          super();
    46          this.setKeyword(DEFAULT_KEYWORD);
    47      }
    48
    49      //~ Methods ================================================================
    50
    51      /***
    52       * Verify if thresold is &gt; 0
    53       *
    54       * @throws Exception if false
    55       */
    56      public void afterPropertiesSet() throws Exception {
    57          super.afterPropertiesSet();
    58          Assert.isTrue(getThresold() > 0, "thresold must be > 0");
    59      }
    60
    61      /***
    62       * Verify wheter the context is valid concerning humanity
    63       *
    64       * @param context
    65       *
    66       * @return true if valid, false otherwise
    67       */
    68      boolean isContextValidConcerningHumanity(CaptchaSecurityContext context) {
    69          int req = context.getHumanRestrictedResourcesRequestsCount();
    70          float thresold = getThresold();
    71          float duration = System.currentTimeMillis()
    72              - context.getLastPassedCaptchaDateInMillis();
    73          float average;
    74
    75          if (req == 0) {
    76              average = thresold + 1;
    77          } else {
    78              average = duration / req;
    79          }
    80
    81          if (context.isHuman() && (average > thresold)) {
    82              logger.debug(
    83                  "context is valid : average time between requests < thresold && is human");
    84
    85              return true;
    86          } else {
    87              logger.debug(
    88                  "context is not valid : request count > thresold or is not human");
    89
    90              return false;
    91          }
    92      }
    93  }