/**
* 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.IOException;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import org.apache.cassandra.db.columniterator.IColumnIterator;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.utils.Pair;
/**
* A SSTableScanner that only reads key in a given range (for validation compaction).
*/
public class SSTableBoundedScanner extends SSTableScanner
{
private final Iterator<Pair<Long, Long>> rangeIterator;
private Pair<Long, Long> currentRange;
SSTableBoundedScanner(SSTableReader sstable, int bufferSize, boolean skipCache, Range range)
{
super(sstable, bufferSize, skipCache);
this.rangeIterator = sstable.getPositionsForRanges(Collections.singletonList(range)).iterator();
if (rangeIterator.hasNext())
{
currentRange = rangeIterator.next();
try
{
file.seek(currentRange.left);
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
else
{
exhausted = true;
}
}
@Override
public boolean hasNext()
{
if (iterator == null)
iterator = exhausted ? Arrays.asList(new IColumnIterator[0]).iterator() : new BoundedKeyScanningIterator();
return iterator.hasNext();
}
@Override
public IColumnIterator next()
{
if (iterator == null)
iterator = exhausted ? Arrays.asList(new IColumnIterator[0]).iterator() : new BoundedKeyScanningIterator();
return iterator.next();
}
protected class BoundedKeyScanningIterator extends KeyScanningIterator
{
@Override
public boolean hasNext()
{
if (!super.hasNext())
return false;
if (finishedAt < currentRange.right)
return true;
if (rangeIterator.hasNext())
{
currentRange = rangeIterator.next();
finishedAt = currentRange.left; // next() will seek for us
return true;
}
else
{
return false;
}
}
}
}