1 /**
2 * This file Copyright (c) 2015 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.entry;
35
36 import info.magnolia.module.cache.filter.CachedEntry;
37
38 import java.io.IOException;
39
40 import javax.servlet.FilterChain;
41 import javax.servlet.ServletException;
42 import javax.servlet.http.HttpServletRequest;
43 import javax.servlet.http.HttpServletResponse;
44
45 /**
46 * An implementation of CachedEntry which simply delegates once and only once to the "super" cachedEntry, for the sake of calling replay() after the entry was added.
47 * Can be replayed only once after creation (for satisfying of the first request).
48 */
49 public class SingleReplayCacheEntryWrapper implements CachedEntry {
50
51 private CachedEntry delegate;
52 private final long lastModificationTime;
53 private final String originalURL;
54
55 public SingleReplayCacheEntryWrapper(CachedEntry delegate) {
56 this.delegate = delegate;
57 //these fields has to be set at this point since delegate=null after replay and these fields are used later e.g. in advanced cache policies
58 this.lastModificationTime = delegate.getLastModificationTime();
59 this.originalURL = delegate.getOriginalURL();
60 }
61
62 @Override
63 public int getTimeToLiveInSeconds() {
64 return -1; //since we can replay the delegate only once, we can cache forever
65 }
66
67 @Override
68 public void replay(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws IOException, ServletException {
69 // First time a page is hit through the cache, concurrent requests are locked.
70 // Once the entry is in the cache entry however, concurrent requests won't be locked anymore.
71 synchronized (this) {
72 if (delegate != null) {
73 delegate.replay(request, response, chain);
74 delegate = null;
75 return;
76 }
77 }
78 throw new IllegalStateException("Already replayed !");
79 }
80
81 @Override
82 public String getOriginalURL() {
83 return originalURL;
84 }
85
86 @Override
87 public long getLastModificationTime() {
88 return lastModificationTime;
89 }
90 }