/**
* This file Copyright (c) 2003-2012 Magnolia International
* Ltd. (http://www.magnolia-cms.com). All rights reserved.
*
*
* This file is dual-licensed under both the Magnolia
* Network Agreement and the GNU General Public License.
* You may elect to use one or the other of these licenses.
*
* This file is distributed in the hope that it will be
* useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
* implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
* Redistribution, except as permitted by whichever of the GPL
* or MNA you select, is prohibited.
*
* 1. For the GPL license (GPL), you can redistribute and/or
* modify this file under the terms of the GNU General
* Public License, Version 3, as published by the Free Software
* Foundation. You should have received a copy of the GNU
* General Public License, Version 3 along with this program;
* if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* 2. For the Magnolia Network Agreement (MNA), this file
* and the accompanying materials are made available under the
* terms of the MNA which accompanies this distribution, and
* is available at http://www.magnolia-cms.com/mna.html
*
* Any modifications to this file must keep this entire header
* intact.
*
*/
package info.magnolia.cms.beans.config;
import info.magnolia.cms.core.Content;
import info.magnolia.cms.core.DefaultContent;
import info.magnolia.cms.util.ObservationUtil;
import info.magnolia.cms.util.SystemContentWrapper;
import info.magnolia.context.MgnlContext;
import info.magnolia.repository.RepositoryConstants;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import javax.jcr.Node;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.observation.EventIterator;
import javax.jcr.observation.EventListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A lot of "manager" objects are observed. Will mean that they reload the registered content after the content was changed. To
* centralize this code we use this abstract manager. A subclass will implement onRegister and onClear.
* @author philipp
*/
public abstract class ObservedManager {
protected final Logger log = LoggerFactory.getLogger(getClass());
/**
* UUIDs of the registered main nodes. They will get registered again after a change.
*/
protected Set<String> registeredUUIDs = new HashSet<String>();
/**
* Register a node. The uuid is cached and then onRegister() called.
* @param node the node to register
*/
public synchronized void register(Content node) {
if (node == null) {
log.warn("Tried to register a non-existing node!");
return;
}
ObservationUtil.registerDeferredChangeListener(RepositoryConstants.CONFIG, node.getHandle(), new EventListener() {
@Override
public void onEvent(EventIterator events) {
reload();
}
}, 1000, 5000);
try {
registeredUUIDs.add(node.getUUID());
onRegister(new SystemContentWrapper(node));
}
catch (Exception e) {
log.warn("Was not able to register [" + node.getHandle() + "]", e);
}
}
/**
* Calls onClear and reregister the nodes by calling onRegister.
*/
public synchronized void reload() {
// Call onClear and reregister the nodes by calling onRegister
onClear();
Session session = null;
try {
session = MgnlContext.getSystemContext().getJCRSession(RepositoryConstants.CONFIG);
} catch (RepositoryException e) {
throw new RuntimeException(e);
}
// copy to avoid ConcurrentModificationException since the list get changed during iteration
List<String> uuids = new ArrayList<String>(registeredUUIDs);
for (Iterator<String> iter = uuids.iterator(); iter.hasNext();) {
String uuid = iter.next();
try {
Node node = session.getNodeByIdentifier(uuid);
reload(new DefaultContent(node));
}
catch (Exception e) {
registeredUUIDs.remove(uuid);
log.warn("Can't reload the the node [" + uuid + "]");
}
}
return;
}
/**
* Reload a specific node.
* @param node
*/
protected void reload(Content node) {
onRegister(node);
}
/**
* Clears the registered UUIDs and calls onClear().
*/
public void clear() {
this.registeredUUIDs.clear();
onClear();
}
/**
* Registers a node.
* @param node
*/
protected abstract void onRegister(Content node);
/**
* The implementor should clear everthing. If needed the nodes will get registered.
*/
protected abstract void onClear();
}