/**
* 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.
*/
package org.apache.cassandra.io.sstable;
import java.io.IOError;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import org.apache.cassandra.db.columniterator.IColumnIteratorFactory;
import org.apache.cassandra.db.columniterator.LazyColumnIterator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.db.compaction.ICompactionScanner;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.RowPosition;
import org.apache.cassandra.db.columniterator.IColumnIterator;
import org.apache.cassandra.db.filter.QueryFilter;
import org.apache.cassandra.io.util.RandomAccessReader;
import org.apache.cassandra.utils.ByteBufferUtil;
public class SSTableScanner implements ICompactionScanner
{
private static Logger logger = LoggerFactory.getLogger(SSTableScanner.class);
protected final RandomAccessReader file;
public final SSTableReader sstable;
private IColumnIterator row;
protected boolean exhausted = false;
protected Iterator<IColumnIterator> iterator;
private QueryFilter filter;
/**
* @param sstable SSTable to scan.
*/
SSTableScanner(SSTableReader sstable, boolean skipCache)
{
try
{
this.file = sstable.openDataReader(skipCache);
}
catch (IOException e)
{
sstable.markSuspect();
throw new IOError(e);
}
this.sstable = sstable;
}
/**
* @param sstable SSTable to scan.
* @param filter filter to use when scanning the columns
*/
SSTableScanner(SSTableReader sstable, QueryFilter filter)
{
try
{
this.file = sstable.openDataReader(false);
}
catch (IOException e)
{
sstable.markSuspect();
throw new IOError(e);
}
this.sstable = sstable;
this.filter = filter;
}
public void close() throws IOException
{
file.close();
}
public void seekTo(RowPosition seekKey)
{
try
{
long position = sstable.getPosition(seekKey, SSTableReader.Operator.GE);
if (position < 0)
{
exhausted = true;
return;
}
file.seek(position);
row = null;
}
catch (IOException e)
{
sstable.markSuspect();
throw new RuntimeException("corrupt sstable", e);
}
}
public long getLengthInBytes()
{
try
{
return file.length();
}
catch (IOException e)
{
throw new IOError(e);
}
}
public long getCurrentPosition()
{
return file.getFilePointer();
}
public String getBackingFiles()
{
return sstable.toString();
}
public boolean hasNext()
{
if (iterator == null)
iterator = exhausted ? Arrays.asList(new IColumnIterator[0]).iterator() : new KeyScanningIterator();
return iterator.hasNext();
}
public IColumnIterator next()
{
if (iterator == null)
iterator = exhausted ? Arrays.asList(new IColumnIterator[0]).iterator() : new KeyScanningIterator();
return iterator.next();
}
public void remove()
{
throw new UnsupportedOperationException();
}
protected class KeyScanningIterator implements Iterator<IColumnIterator>
{
protected long finishedAt;
public boolean hasNext()
{
try
{
if (row == null)
return !file.isEOF();
return finishedAt < file.length();
}
catch (IOException e)
{
sstable.markSuspect();
throw new RuntimeException(e);
}
}
public IColumnIterator next()
{
try
{
if (row != null)
file.seek(finishedAt);
assert !file.isEOF();
final DecoratedKey<?> key = SSTableReader.decodeKey(sstable.partitioner,
sstable.descriptor,
ByteBufferUtil.readWithShortLength(file));
long dataSize = SSTableReader.readRowSize(file, sstable.descriptor);
long dataStart = file.getFilePointer();
finishedAt = dataStart + dataSize;
if (filter == null)
{
row = new SSTableIdentityIterator(sstable, file, key, dataStart, dataSize);
return row;
}
else
{
return row = new LazyColumnIterator(key, new IColumnIteratorFactory()
{
public IColumnIterator create()
{
return filter.getSSTableColumnIterator(sstable, file, key);
}
});
}
}
catch (IOException e)
{
sstable.markSuspect();
throw new RuntimeException(SSTableScanner.this + " failed to provide next columns from " + this, e);
}
}
public void remove()
{
throw new UnsupportedOperationException();
}
@Override
public String toString() {
return getClass().getSimpleName() + "(" +
"finishedAt:" + finishedAt +
")";
}
}
@Override
public String toString() {
return getClass().getSimpleName() + "(" +
"file=" + file +
" sstable=" + sstable +
" exhausted=" + exhausted +
")";
}
}