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