/*
* Copyright (C) 2009 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.services.jcr.impl.core.query.jbosscache;
import org.exoplatform.services.jcr.impl.core.query.IndexerIoMode;
import org.exoplatform.services.jcr.impl.core.query.IndexerIoModeHandler;
import org.exoplatform.services.jcr.impl.core.query.IndexerIoModeListener;
import org.exoplatform.services.jcr.impl.core.query.lucene.IndexInfos;
import org.exoplatform.services.jcr.impl.core.query.lucene.MultiIndex;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.jboss.cache.Cache;
import org.jboss.cache.Fqn;
import org.jboss.cache.Node;
import org.jboss.cache.notifications.annotation.CacheListener;
import org.jboss.cache.notifications.annotation.NodeModified;
import org.jboss.cache.notifications.event.NodeModifiedEvent;
import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import java.util.Set;
/**
* List of indexes is stored in FS and all operations with it are wrapped by IndexInfos class. In
* standalone mode index and so the list of indexes are managed by indexer and can't be changed
* externally.
* But in cluster environment all JCR Indexers are reading from shared file system and only one
* cluster node is writing this index. So read-only cluster nodes should be notified when content
* of index (actually list of index segments) is changed.
* This class is responsible for storing list of segments (indexes) in distributed JBoss Cache
* instance.
*
* @author <a href="mailto:nikolazius@gmail.com">Nikolay Zamosenchuk</a>
* @version $Id: JbossCacheIndexInfos.java 34360 2009-07-22 23:58:59Z nzamosenchuk $
*
*/
@CacheListener
public class JBossCacheIndexInfos extends IndexInfos implements IndexerIoModeListener
{
private final Log log = ExoLogger.getLogger(this.getClass().getName());
private static final String INDEX_NAMES = "$names".intern();
private static final String SYSINDEX_NAMES = "$sysNames".intern();
private static final String LIST_KEY = "$listOfIndexes".intern();
private final Cache<Serializable, Object> cache;
/**
* Flag notifies if this IndexInfos is from system search manager or not.
*/
private boolean system;
/**
* Used to retrieve the current mode
*/
private final IndexerIoModeHandler modeHandler;
/**
* This FQN points to cache node, where list of indexes for this {@link IndexInfos} instance is stored.
*/
private final Fqn namesFqn;
/**
* @param cache instance of JbossCache that is used to deliver index names
*/
public JBossCacheIndexInfos(Cache<Serializable, Object> cache, boolean system, IndexerIoModeHandler modeHandler)
{
this(DEFALUT_NAME, cache, system, modeHandler);
}
/**
* @param fileName where index names are stored.
* @param cache instance of JbossCache that is used to deliver index names
*/
public JBossCacheIndexInfos(String fileName, Cache<Serializable, Object> cache, boolean system,
IndexerIoModeHandler modeHandler)
{
super(fileName);
this.cache = cache;
this.modeHandler = modeHandler;
modeHandler.addIndexerIoModeListener(this);
// store parsed FQN to avoid it's parsing each time cache event is generated
namesFqn = Fqn.fromString(system ? SYSINDEX_NAMES : INDEX_NAMES);
Node<Serializable, Object> cacheRoot = cache.getRoot();
// prepare cache structures
if (!cacheRoot.hasChild(namesFqn))
{
cache.getInvocationContext().getOptionOverrides().setCacheModeLocal(true);
cacheRoot.addChild(namesFqn).setResident(true);
}
else
{
cache.getNode(namesFqn).setResident(true);
}
if (modeHandler.getMode() == IndexerIoMode.READ_ONLY)
{
// Currently READ_ONLY is set, so new lists should be fired to multiIndex.
cache.addCacheListener(this);
}
}
/**
* @see org.exoplatform.services.jcr.impl.core.query.IndexerIoModeListener#onChangeMode(org.exoplatform.services.jcr.impl.core.query.IndexerIoMode)
*/
public void onChangeMode(IndexerIoMode mode)
{
if (mode == IndexerIoMode.READ_WRITE)
{
// Now is read-write. Index list is actual and shouldn't be refreshed.
// Remove listener to avoid asserting if ioMode is RO on each cache event
cache.removeCacheListener(this);
// re-read from FS current actual list.
try
{
super.read();
}
catch (IOException e)
{
log.error("Cannot read the list of indexe names", e);
}
}
else
{
// Currently READ_ONLY is set, so new lists should be fired to multiIndex.
cache.addCacheListener(this);
}
}
/**
* @see org.exoplatform.services.jcr.impl.core.query.lucene.IndexInfos#write()
*/
@Override
public void write() throws IOException
{
// if READ_WRITE and is dirty, then flush.
if (isDirty() && modeHandler.getMode() == IndexerIoMode.READ_WRITE)
{
// write to FS
super.write();
// write to cache
cache.put(namesFqn, LIST_KEY, getNames());
}
}
/**
* CacheListener method, that accepts event, when cache node changed. This class is registered as cache listener,
* only in READ_ONLY mode.
* @param event
*/
@NodeModified
public void cacheNodeModified(NodeModifiedEvent event)
{
if (!event.isPre() && event.getFqn().equals(namesFqn))
{
Set<String> set = null;
Map<?, ?> data = event.getData();
if (data == null)
{
log.warn("The data map is empty");
}
else
{
set = (Set<String>)data.get(LIST_KEY);
}
if (set == null)
{
log.warn("The data cannot be found, we will try to get it from the cache");
// read from cache to update lists
set = (Set<String>)cache.get(namesFqn, LIST_KEY);
}
if (set != null)
{
setNames(set);
// callback multiIndex to refresh lists
try
{
MultiIndex multiIndex = getMultiIndex();
if (multiIndex != null)
{
multiIndex.refreshIndexList();
}
}
catch (IOException e)
{
log.error("Failed to update indexes! " + e.getMessage(), e);
}
}
}
}
}