1 /**
2 * This file Copyright (c) 2003-2010 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 * A lot of "manager" objects are observed. Will mean that they reload the
56 * registered content after the content was changed. To centralize this code we
57 * use this abstract manager. A subclass will implement onRegister and onClear.
58 *
59 * @author philipp
60 */
61 public abstract class ObservedManager {
62 protected final Logger log = LoggerFactory.getLogger(getClass());
63
64 /**
65 * UUIDs of the registered main nodes. They will get registered again after
66 * a change.
67 */
68 protected Set registeredUUIDs = new HashSet();
69
70 /**
71 * Register a node. The uuid is cached and then onRegister() called.
72 *
73 * @param node
74 * 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(ContentRepository.CONFIG, node.getHandle(), new EventListener() {
83
84 public void onEvent(EventIterator events) {
85 reload();
86 }
87 }, 1000, 5000);
88
89 try {
90 registeredUUIDs.add(node.getUUID());
91 onRegister(new SystemContentWrapper(node));
92 } catch (Exception e) {
93 log.warn("Was not able to register [" + node.getHandle() + "]", e);
94 }
95 }
96
97 /**
98 * Calls onClear and reregister the nodes by calling onRegister.
99 */
100 public synchronized void reload() {
101 // Call onClear and reregister the nodes by calling onRegister
102 onClear();
103
104 HierarchyManager hm = MgnlContext.getSystemContext().getHierarchyManager(ContentRepository.CONFIG);
105
106 // copy to avoid ConcurrentModificationException since the list get
107 // changed during iteration
108 List uuids = new ArrayList(registeredUUIDs);
109
110 for (Iterator iter = uuids.iterator(); iter.hasNext();) {
111 String uuid = (String) iter.next();
112 try {
113 Content node = hm.getContentByUUID(uuid);
114 reload(node);
115 } catch (Exception e) {
116 registeredUUIDs.remove(uuid);
117 log.warn("Can't reload the node [" + uuid + "]");
118 }
119 }
120 return;
121 }
122
123 /**
124 * Reload a specific node.
125 *
126 * @param node
127 */
128 protected void reload(Content node) {
129 onRegister(node);
130 }
131
132 /**
133 * Clears the registered UUIDs and calls onClear().
134 */
135 public void clear() {
136 this.registeredUUIDs.clear();
137 onClear();
138 }
139
140 /**
141 * Registers a node.
142 *
143 * @param node
144 */
145 protected abstract void onRegister(Content node);
146
147 /**
148 * The implementor should clear everthing. If needed the nodes will get
149 * registered.
150 */
151 protected abstract void onClear();
152
153 }