/**
* Copyright (C) 2011 the original author or authors.
* See the notice.md file distributed with this work for additional
* information regarding copyright ownership.
*
* Licensed 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.
*/
package org.iq80.leveldb.impl;
import com.google.common.base.Preconditions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import org.iq80.leveldb.util.Closeables;
import org.iq80.leveldb.table.FileChannelTable;
import org.iq80.leveldb.table.MMapTable;
import org.iq80.leveldb.table.Table;
import org.iq80.leveldb.table.UserComparator;
import org.iq80.leveldb.util.Finalizer;
import org.iq80.leveldb.util.InternalTableIterator;
import org.iq80.leveldb.util.Slice;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.util.concurrent.ExecutionException;
public class TableCache
{
private final LoadingCache<Long, TableAndFile> cache;
private final Finalizer<Table> finalizer = new Finalizer<Table>(1);
public TableCache(final File databaseDir, int tableCacheSize, final UserComparator userComparator, final boolean verifyChecksums)
{
Preconditions.checkNotNull(databaseDir, "databaseName is null");
cache = CacheBuilder.newBuilder()
.maximumSize(tableCacheSize)
.removalListener(new RemovalListener<Long, TableAndFile>() {
public void onRemoval(RemovalNotification<Long, TableAndFile> notification) {
Table table = notification.getValue().getTable();
finalizer.addCleanup(table, table.closer());
}
})
.build(new CacheLoader<Long, TableAndFile>() {
public TableAndFile load(Long fileNumber)
throws IOException {
return new TableAndFile(databaseDir, fileNumber, userComparator, verifyChecksums);
}
});
}
public InternalTableIterator newIterator(FileMetaData file)
{
return newIterator(file.getNumber());
}
public InternalTableIterator newIterator(long number)
{
return new InternalTableIterator(getTable(number).iterator());
}
public long getApproximateOffsetOf(FileMetaData file, Slice key) {
return getTable(file.getNumber()).getApproximateOffsetOf(key);
}
private Table getTable(long number)
{
Table table;
try {
table = cache.get(number).getTable();
}
catch (ExecutionException e) {
Throwable cause = e;
if (e.getCause() != null) {
cause = e.getCause();
}
throw new RuntimeException("Could not open table " + number, cause);
}
return table;
}
public void close() {
cache.invalidateAll();
finalizer.destroy();
}
public void evict(long number)
{
cache.invalidate(number);
}
private static final class TableAndFile
{
private final Table table;
private final FileChannel fileChannel;
private TableAndFile(File databaseDir, long fileNumber, UserComparator userComparator, boolean verifyChecksums)
throws IOException
{
String tableFileName = Filename.tableFileName(fileNumber);
File tableFile = new File(databaseDir, tableFileName);
fileChannel = new FileInputStream(tableFile).getChannel();
try {
if( Iq80DBFactory.USE_MMAP ) {
table = new MMapTable(tableFile.getAbsolutePath(), fileChannel, userComparator, verifyChecksums);
} else {
table = new FileChannelTable(tableFile.getAbsolutePath(), fileChannel, userComparator, verifyChecksums);
}
}
catch (IOException e) {
Closeables.closeQuietly(fileChannel);
throw e;
}
}
public Table getTable()
{
return table;
}
}
}