1 /**
2 * This file Copyright (c) 2003-2011 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.cms.beans.config;
35
36 import info.magnolia.cms.core.Content;
37 import info.magnolia.cms.core.HierarchyManager;
38 import info.magnolia.cms.util.ObservationUtil;
39 import info.magnolia.cms.util.SystemContentWrapper;
40 import info.magnolia.context.MgnlContext;
41
42 import java.util.ArrayList;
43 import java.util.HashSet;
44 import java.util.Iterator;
45 import java.util.List;
46 import java.util.Set;
47
48 import javax.jcr.observation.EventIterator;
49 import javax.jcr.observation.EventListener;
50
51 import org.slf4j.Logger;
52 import org.slf4j.LoggerFactory;
53
54
55 /**
56 * A lot of "manager" objects are observed. Will mean that they reload the registered content after the content was changed. To
57 * centralize this code we use this abstract manager. A subclass will implement onRegister and onClear.
58 * @author philipp
59 */
60 public abstract class ObservedManager {
61 protected final Logger log = LoggerFactory.getLogger(getClass());
62
63 /**
64 * UUIDs of the registered main nodes. They will get registered again after a change.
65 */
66 protected Set<String> registeredUUIDs = new HashSet<String>();
67
68 /**
69 * Register a node. The uuid is cached and then onRegister() called.
70 * @param node the node to register
71 */
72 public synchronized void register(Content node) {
73 if (node == null) {
74 log.warn("Tried to register a non-existing node!");
75 return;
76 }
77
78 ObservationUtil.registerDeferredChangeListener(ContentRepository.CONFIG, node.getHandle(), new EventListener() {
79
80 public void onEvent(EventIterator events) {
81 reload();
82 }
83 }, 1000, 5000);
84
85 try {
86 registeredUUIDs.add(node.getUUID());
87 onRegister(new SystemContentWrapper(node));
88 }
89 catch (Exception e) {
90 log.warn("Was not able to register [" + node.getHandle() + "]", e);
91 }
92 }
93
94 /**
95 * Calls onClear and reregister the nodes by calling onRegister.
96 */
97 public synchronized void reload() {
98 // Call onClear and reregister the nodes by calling onRegister
99 onClear();
100
101 HierarchyManager hm = MgnlContext.getSystemContext().getHierarchyManager(ContentRepository.CONFIG);
102
103 // copy to avoid ConcurrentModificationException since the list get changed during iteration
104 List<String> uuids = new ArrayList<String>(registeredUUIDs);
105
106 for (Iterator<String> iter = uuids.iterator(); iter.hasNext();) {
107 String uuid = iter.next();
108 try {
109 Content node = hm.getContentByUUID(uuid);
110 reload(node);
111 }
112 catch (Exception e) {
113 registeredUUIDs.remove(uuid);
114 log.warn("Can't reload the the node [" + uuid + "]");
115 }
116 }
117 return;
118 }
119
120 /**
121 * Reload a specific node.
122 * @param node
123 */
124 protected void reload(Content node) {
125 onRegister(node);
126 }
127
128 /**
129 * Clears the registered UUIDs and calls onClear().
130 */
131 public void clear() {
132 this.registeredUUIDs.clear();
133 onClear();
134 }
135
136 /**
137 * Registers a node.
138 * @param node
139 */
140 protected abstract void onRegister(Content node);
141
142 /**
143 * The implementor should clear everything. If needed the nodes will get registered.
144 */
145 protected abstract void onClear();
146
147 }