package proj.zoie.impl.indexing.internal;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import org.apache.lucene.index.IndexCommit;
import org.apache.lucene.index.IndexDeletionPolicy;
/**
* @author ymatsuda
*
*/
public class ZoieIndexDeletionPolicy implements IndexDeletionPolicy
{
private IndexCommit _lastCommit;
private HashMap<String,Snapshot> _currentSnapshots = new HashMap<String,Snapshot>();
public ZoieIndexDeletionPolicy()
{
_lastCommit = null;
}
public void onInit(List commits) throws IOException
{
processCommits(commits);
}
public void onCommit(List commits) throws IOException
{
processCommits(commits);
}
private synchronized void processCommits(List commits)
{
int size = commits.size();
if(size == 0) return;
IndexCommit indexCommit = null;
for(Object commit : commits)
{
indexCommit = (IndexCommit)commit;
if(--size > 0 && !_currentSnapshots.containsKey(indexCommit.getSegmentsFileName()))
{
indexCommit.delete();
}
}
_lastCommit = indexCommit;
}
public synchronized Snapshot getSnapshot()
{
if(_lastCommit == null) return null; // no commit yet
Snapshot snapshot;
synchronized(_currentSnapshots)
{
String name = _lastCommit.getSegmentsFileName();
snapshot = _currentSnapshots.get(name);
if(snapshot == null)
{
snapshot = new Snapshot(_lastCommit);
_currentSnapshots.put(name, snapshot);
}
else
{
snapshot.incRef();
}
}
return snapshot;
}
public class Snapshot
{
private final IndexCommit _commit;
private int _refcount;
public Snapshot(IndexCommit commit)
{
_commit = commit;
_refcount = 1;
}
public Collection<String> getFileNames() throws IOException
{
return (Collection<String>)_commit.getFileNames();
}
public void close()
{
decRef();
}
private synchronized void incRef()
{
_refcount++;
}
private synchronized void decRef()
{
if(--_refcount <= 0)
{
synchronized(_currentSnapshots)
{
_currentSnapshots.remove(_commit.getSegmentsFileName());
}
}
}
public void finalize()
{
_refcount = 0;
close();
}
}
}