1 /**
2 * This file Copyright (c) 2003-2013 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.cms.beans.config;
35
36 import info.magnolia.cms.core.Content;
37 import info.magnolia.cms.core.DefaultContent;
38 import info.magnolia.cms.util.ObservationUtil;
39 import info.magnolia.cms.util.SystemContentWrapper;
40 import info.magnolia.context.MgnlContext;
41 import info.magnolia.repository.RepositoryConstants;
42
43 import java.util.ArrayList;
44 import java.util.HashSet;
45 import java.util.Iterator;
46 import java.util.List;
47 import java.util.Set;
48
49 import javax.jcr.Node;
50 import javax.jcr.RepositoryException;
51 import javax.jcr.Session;
52 import javax.jcr.observation.EventIterator;
53 import javax.jcr.observation.EventListener;
54
55 import org.slf4j.Logger;
56 import org.slf4j.LoggerFactory;
57
58
59 /**
60 * A lot of "manager" objects are observed. Will mean that they reload the registered content after the content was changed. To
61 * centralize this code we use this abstract manager. A subclass will implement onRegister and onClear.
62 * @author philipp
63 */
64 public abstract class ObservedManager {
65 protected final Logger log = LoggerFactory.getLogger(getClass());
66
67 /**
68 * UUIDs of the registered main nodes. They will get registered again after a change.
69 */
70 protected Set<String> registeredUUIDs = new HashSet<String>();
71
72 /**
73 * Register a node. The uuid is cached and then onRegister() called.
74 * @param node the node to register
75 */
76 public synchronized void register(Content node) {
77 if (node == null) {
78 log.warn("Tried to register a non-existing node!");
79 return;
80 }
81
82 ObservationUtil.registerDeferredChangeListener(RepositoryConstants.CONFIG, node.getHandle(), new EventListener() {
83
84 @Override
85 public void onEvent(EventIterator events) {
86 reload();
87 }
88 }, 1000, 5000);
89
90 try {
91 registeredUUIDs.add(node.getUUID());
92 onRegister(new SystemContentWrapper(node));
93 }
94 catch (Exception e) {
95 log.warn("Was not able to register [" + node.getHandle() + "]", e);
96 }
97 }
98
99 /**
100 * Calls onClear and reregister the nodes by calling onRegister.
101 */
102 public synchronized void reload() {
103 // Call onClear and reregister the nodes by calling onRegister
104 onClear();
105
106 Session session = null;
107 try {
108 session = MgnlContext.getSystemContext().getJCRSession(RepositoryConstants.CONFIG);
109 } catch (RepositoryException e) {
110 throw new RuntimeException(e);
111 }
112
113 // copy to avoid ConcurrentModificationException since the list get changed during iteration
114 List<String> uuids = new ArrayList<String>(registeredUUIDs);
115
116 for (Iterator<String> iter = uuids.iterator(); iter.hasNext();) {
117 String uuid = iter.next();
118 try {
119 Node node = session.getNodeByIdentifier(uuid);
120 reload(new DefaultContent(node));
121 }
122 catch (Exception e) {
123 registeredUUIDs.remove(uuid);
124 log.warn("Can't reload the the node [" + uuid + "]");
125 }
126 }
127 return;
128 }
129
130 /**
131 * Reload a specific node.
132 * @param node
133 */
134 protected void reload(Content node) {
135 onRegister(node);
136 }
137
138 /**
139 * Clears the registered UUIDs and calls onClear().
140 */
141 public void clear() {
142 this.registeredUUIDs.clear();
143 onClear();
144 }
145
146 /**
147 * Registers a node.
148 * @param node
149 */
150 protected abstract void onRegister(Content node);
151
152 /**
153 * The implementor should clear everthing. If needed the nodes will get registered.
154 */
155 protected abstract void onClear();
156
157 }