OncePerRequestInterceptor


1   /* ***** BEGIN LICENSE BLOCK *****
2    * Version: MPL 1.1
3    * The contents of this file are subject to the Mozilla Public License Version
4    * 1.1 (the "License"); you may not use this file except in compliance with
5    * the License. You may obtain a copy of the License at
6    * http://www.mozilla.org/MPL/
7    * 
8    * Software distributed under the License is distributed on an "AS IS" basis,
9    * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
10   * for the specific language governing rights and limitations under the
11   * License.
12   * 
13   * The Original Code is Riot.
14   * 
15   * The Initial Developer of the Original Code is
16   * Neteye GmbH.
17   * Portions created by the Initial Developer are Copyright (C) 2006
18   * the Initial Developer. All Rights Reserved.
19   * 
20   * Contributor(s):
21   *   Felix Gnass [fgnass at neteye dot de]
22   * 
23   * ***** END LICENSE BLOCK ***** */
24  package org.riotfamily.common.web.util;
25  
26  import javax.servlet.http.HttpServletRequest  ;
27  import javax.servlet.http.HttpServletResponse  ;
28  
29  public abstract class OncePerRequestInterceptor extends PathMatchingInterceptor {
30  
31      private String   counterAttribute = getClass().getName() + ".interceptions";
32  
33      protected final boolean doPreHandle(HttpServletRequest   request,
34              HttpServletResponse   response, Object   handler) throws Exception   {
35  
36          int interceptions = 0;
37          Integer   counter = (Integer  ) request.getAttribute(counterAttribute);
38          if (counter != null) {
39              interceptions = counter.intValue();
40          }
41          interceptions++;
42          request.setAttribute(counterAttribute, new Integer  (interceptions));
43  
44          if (interceptions == 1) {
45              return preHandleOnce(request, response, handler);
46          }
47          
48          return true;
49      }
50  
51      protected boolean preHandleOnce(HttpServletRequest   request,
52              HttpServletResponse   response, Object   handler) throws Exception   {
53          
54          return true;
55      }
56      
57      public final void afterCompletion(HttpServletRequest   request,
58              HttpServletResponse   response, Object   handler, Exception   exception)
59              throws Exception   {
60          
61          Integer   counter = (Integer  ) request.getAttribute(counterAttribute);
62          if (counter != null) {
63              int interceptions = counter.intValue() - 1;
64              request.setAttribute(counterAttribute, new Integer  (interceptions));
65              if (interceptions == 0) {
66                  afterLastCompletion(request, response, handler, exception);
67              }
68          }
69      }
70  
71      protected void afterLastCompletion(HttpServletRequest   request,
72              HttpServletResponse   response, Object   handler, Exception   exception)
73              throws Exception   {
74      }
75  
76  }
77
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