1 /**
2 * This file Copyright (c) 2008-2011 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.module.cache.executor;
35
36 import info.magnolia.module.cache.Cache;
37 import info.magnolia.module.cache.CachePolicyResult;
38 import info.magnolia.module.cache.filter.CachedEntry;
39 import info.magnolia.module.cache.filter.ContentCachedEntry;
40
41 import java.io.IOException;
42
43 import javax.servlet.FilterChain;
44 import javax.servlet.ServletException;
45 import javax.servlet.http.HttpServletRequest;
46 import javax.servlet.http.HttpServletResponse;
47
48 /**
49 * Serves the content from the cache.
50 *
51 * @author pbracher
52 * @version $Revision: $ ($Author: $)
53 */
54 public class UseCache extends AbstractExecutor {
55 private final static org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(UseCache.class);
56
57 public void processCacheRequest(HttpServletRequest request,
58 HttpServletResponse response, FilterChain chain, Cache cache,
59 CachePolicyResult cachePolicy) throws IOException, ServletException {
60 CachedEntry cached = (CachedEntry) cachePolicy.getCachedEntry();
61 processCachedEntry(cached, request, response, chain);
62 }
63
64 protected void processCachedEntry(CachedEntry cached, HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
65 log.debug("Serving {}", cached);
66 if (cached instanceof ContentCachedEntry) {
67 final ContentCachedEntry page = (ContentCachedEntry) cached;
68 if (!ifModifiedSince(request, page.getLastModificationTime())) {
69 if (response.isCommitted()) {
70 // this should not happen ... if it does, log it and _serve_the_data_ otherwise we will confuse client
71 log.warn("Unable to change status on already commited response {}.", response.getClass().getName());
72 } else {
73 response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
74 return;
75 }
76 }
77
78
79 }
80
81 if (cached != null) {
82 cached.replay(request, response, chain);
83 response.flushBuffer();
84 } else {
85 // not modified (304) or nothing to write to the output
86 }
87 }
88
89 }