package org.apache.cassandra.db.columniterator;
/*
*
* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
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import java.io.IOError;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.IColumn;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.io.sstable.IndexHelper;
import org.apache.cassandra.io.sstable.SSTableReader;
import org.apache.cassandra.io.util.FileDataInput;
import org.apache.cassandra.io.util.FileMark;
import org.apache.cassandra.io.util.FileUtils;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.Filter;
public class SSTableNamesIterator extends SimpleAbstractColumnIterator implements IColumnIterator
{
private static Logger logger = LoggerFactory.getLogger(SSTableNamesIterator.class);
private ColumnFamily cf;
private Iterator<IColumn> iter;
public final SortedSet<ByteBuffer> columns;
public final DecoratedKey key;
public SSTableNamesIterator(SSTableReader sstable, DecoratedKey key, SortedSet<ByteBuffer> columns)
{
assert columns != null;
this.columns = columns;
this.key = key;
FileDataInput file = sstable.getFileDataInput(key, DatabaseDescriptor.getIndexedReadBufferSizeInKB() * 1024);
if (file == null)
return;
try
{
DecoratedKey keyInDisk = SSTableReader.decodeKey(sstable.partitioner,
sstable.descriptor,
ByteBufferUtil.readWithShortLength(file));
assert keyInDisk.equals(key) : String.format("%s != %s in %s", keyInDisk, key, file.getPath());
SSTableReader.readRowSize(file, sstable.descriptor);
read(sstable, file);
}
catch (IOException e)
{
throw new IOError(e);
}
finally
{
FileUtils.closeQuietly(file);
}
}
public SSTableNamesIterator(SSTableReader sstable, FileDataInput file, DecoratedKey key, SortedSet<ByteBuffer> columns)
{
assert columns != null;
this.columns = columns;
this.key = key;
try
{
read(sstable, file);
}
catch (IOException ioe)
{
throw new IOError(ioe);
}
}
private void read(SSTableReader sstable, FileDataInput file)
throws IOException
{
// read the requested columns into `cf`
/* Read the bloom filter summarizing the columns */
Filter bf = IndexHelper.defreezeBloomFilter(file, sstable.descriptor.usesOldBloomFilter);
List<IndexHelper.IndexInfo> indexList = IndexHelper.deserializeIndex(file);
// we can stop early if bloom filter says none of the columns actually exist -- but,
// we can't stop before initializing the cf above, in case there's a relevant tombstone
cf = ColumnFamily.serializer().deserializeFromSSTableNoColumns(ColumnFamily.create(sstable.metadata), file);
List<ByteBuffer> filteredColumnNames = new ArrayList<ByteBuffer>(columns.size());
for (ByteBuffer name : columns)
{
if (bf.isPresent(name))
{
filteredColumnNames.add(name);
}
}
if (filteredColumnNames.isEmpty())
return;
if (indexList == null)
readSimpleColumns(file, columns, filteredColumnNames);
else
readIndexedColumns(sstable.metadata, file, columns, filteredColumnNames, indexList);
// create an iterator view of the columns we read
iter = cf.getSortedColumns().iterator();
}
private void readSimpleColumns(FileDataInput file, SortedSet<ByteBuffer> columnNames, List<ByteBuffer> filteredColumnNames) throws IOException
{
int columns = file.readInt();
int n = 0;
for (int i = 0; i < columns; i++)
{
IColumn column = cf.getColumnSerializer().deserialize(file);
if (columnNames.contains(column.name()))
{
cf.addColumn(column);
if (n++ > filteredColumnNames.size())
break;
}
}
}
private void readIndexedColumns(CFMetaData metadata, FileDataInput file, SortedSet<ByteBuffer> columnNames, List<ByteBuffer> filteredColumnNames, List<IndexHelper.IndexInfo> indexList)
throws IOException
{
file.readInt(); // column count
/* get the various column ranges we have to read */
AbstractType comparator = metadata.comparator;
SortedSet<IndexHelper.IndexInfo> ranges = new TreeSet<IndexHelper.IndexInfo>(IndexHelper.getComparator(comparator));
for (ByteBuffer name : filteredColumnNames)
{
int index = IndexHelper.indexFor(name, indexList, comparator, false);
if (index == indexList.size())
continue;
IndexHelper.IndexInfo indexInfo = indexList.get(index);
if (comparator.compare(name, indexInfo.firstName) < 0)
continue;
ranges.add(indexInfo);
}
FileMark mark = file.mark();
for (IndexHelper.IndexInfo indexInfo : ranges)
{
file.reset(mark);
long curOffsert = file.skipBytes((int) indexInfo.offset);
assert curOffsert == indexInfo.offset;
// TODO only completely deserialize columns we are interested in
while (file.bytesPastMark(mark) < indexInfo.offset + indexInfo.width)
{
IColumn column = cf.getColumnSerializer().deserialize(file);
// we check vs the original Set, not the filtered List, for efficiency
if (columnNames.contains(column.name()))
{
cf.addColumn(column);
}
}
}
}
public DecoratedKey getKey()
{
return key;
}
public ColumnFamily getColumnFamily()
{
return cf;
}
protected IColumn computeNext()
{
if (iter == null || !iter.hasNext())
return endOfData();
return iter.next();
}
}