1   /**
2    * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
3    *
4    * This library is free software; you can redistribute it and/or modify it under
5    * the terms of the GNU Lesser General Public License as published by the Free
6    * Software Foundation; either version 2.1 of the License, or (at your option)
7    * any later version.
8    *
9    * This library is distributed in the hope that it will be useful, but WITHOUT
10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11   * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
12   * details.
13   */
14  
15  package com.liferay.portal.servlet.filters.etag;
16  
17  import com.liferay.portal.kernel.servlet.StringServletResponse;
18  import com.liferay.portal.kernel.util.ParamUtil;
19  import com.liferay.portal.servlet.filters.BasePortalFilter;
20  import com.liferay.util.servlet.ServletResponseUtil;
21  
22  import javax.servlet.FilterChain;
23  import javax.servlet.http.HttpServletRequest;
24  import javax.servlet.http.HttpServletResponse;
25  
26  /**
27   * <a href="ETagFilter.java.html"><b><i>View Source</i></b></a>
28   *
29   * @author Eduardo Lundgren
30   * @author Brian Wing Shun Chan
31   * @author Raymond Augé
32   * @author Shuyang Zhou
33   */
34  public class ETagFilter extends BasePortalFilter {
35  
36      protected void processFilter(
37              HttpServletRequest request, HttpServletResponse response,
38              FilterChain filterChain)
39          throws Exception {
40  
41          boolean etag = ParamUtil.getBoolean(request, _ETAG, true);
42  
43          if (etag) {
44              StringServletResponse stringResponse =
45                  new StringServletResponse(response);
46  
47              processFilter(
48                  ETagFilter.class, request, stringResponse, filterChain);
49  
50              if (!ETagUtil.processETag(request, response, stringResponse)) {
51                  ServletResponseUtil.write(response, stringResponse);
52              }
53          }
54          else {
55              processFilter(ETagFilter.class, request, response, filterChain);
56          }
57      }
58  
59      private static final String _ETAG = "etag";
60  
61  }