ExpiryHandler


1   // ========================================================================
2   // $Id: ExpiryHandler.java,v 1.11 2005/08/13 00:01:26 gregwilkins Exp $
3   // Copyright 2002-2004 Mort Bay Consulting Pty. Ltd.
4   // ------------------------------------------------------------------------
5   // Licensed under the Apache License, Version 2.0 (the "License");
6   // you may not use this file except in compliance with the License.
7   // You may obtain a copy of the License at 
8   // http://www.apache.org/licenses/LICENSE-2.0
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.mortbay.http.handler;
17  
18  import java.io.IOException  ;
19  
20  import org.apache.commons.logging.Log;
21  import org.mortbay.log.LogFactory;
22  import org.mortbay.http.HttpException;
23  import org.mortbay.http.HttpFields;
24  import org.mortbay.http.HttpRequest;
25  import org.mortbay.http.HttpResponse;
26  
27  /* ------------------------------------------------------------ */
28  /**
29   * Handler that allows the default Expiry of all content to be set.
30   *
31   * @version $Id: ExpiryHandler.java,v 1.11 2005/08/13 00:01:26 gregwilkins Exp $
32   * @author Brett Sealey
33   */
34  public class ExpiryHandler extends AbstractHttpHandler
35  {
36      private static Log log = LogFactory.getLog(ExpiryHandler.class);
37  
38      /**
39       * The default expiry time in seconds
40       */
41      private long _ttl=-1;
42  
43      /* ------------------------------------------------------------ */
44      /**
45       * Set the default expiry time in seconds.
46       *
47       * @param ttl The default time to live in seconds. If negative (the
48       * default) then all content will be set to expire 01Jan1970 by default.
49       */
50      public void setTimeToLive(long ttl)
51      {
52          _ttl=ttl;
53      }
54  
55      /* ------------------------------------------------------------ */
56      /** Handle a request by pre-populating the Expires header with a a value
57       * that corresponds to now + ttl. If ttl -s negative then
58       * HttpFields.__01Jan1970 is used.
59       *
60       * Settings made here can be overridden by subsequent handling of the
61       * request.
62       *
63       * @param pathInContext The context path
64       * @param pathParams Path parameters such as encoded Session ID
65       * @param request The HttpRequest request
66       * @param response The HttpResponse response
67       */
68      public void handle(String   pathInContext,
69                         String   pathParams,
70                         HttpRequest request,
71                         HttpResponse response)
72              throws HttpException,IOException  
73      {
74          log.debug("ExpiryHandler.handle()");
75          String   expires;
76          if (_ttl<0)
77              expires=HttpFields.__01Jan1970;
78          else
79              expires=HttpFields.formatDate
80                (System.currentTimeMillis()+1000L*_ttl,false);
81          response.setField(HttpFields.__Expires,expires);
82      }
83  }
84
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