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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.File;
import java.io.IOException;
import org.apache.cassandra.utils.AbstractIterator;
import org.apache.cassandra.config.CFMetaData;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.RowIndexEntry;
import org.apache.cassandra.dht.IPartitioner;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.RandomAccessReader;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.CloseableIterator;
public class KeyIterator extends AbstractIterator implements CloseableIterator
{
private final static class In
{
private final File path;
private RandomAccessReader in;
public In(File path)
{
this.path = path;
}
private void maybeInit()
{
if (in == null)
in = RandomAccessReader.open(path);
}
public DataInputPlus get()
{
maybeInit();
return in;
}
public boolean isEOF()
{
maybeInit();
return in.isEOF();
}
public void close()
{
if (in != null)
in.close();
}
public long getFilePointer()
{
maybeInit();
return in.getFilePointer();
}
public long length()
{
maybeInit();
return in.length();
}
}
private final Descriptor desc;
private final In in;
private final IPartitioner partitioner;
private long keyPosition;
public KeyIterator(Descriptor desc, CFMetaData metadata)
{
this.desc = desc;
in = new In(new File(desc.filenameFor(Component.PRIMARY_INDEX)));
partitioner = metadata.partitioner;
}
protected DecoratedKey computeNext()
{
try
{
if (in.isEOF())
return endOfData();
keyPosition = in.getFilePointer();
DecoratedKey key = partitioner.decorateKey(ByteBufferUtil.readWithShortLength(in.get()));
RowIndexEntry.Serializer.skip(in.get(), desc.version); // skip remainder of the entry
return key;
}
catch (IOException e)
{
throw new RuntimeException(e);
}
}
public void close()
{
in.close();
}
public long getBytesRead()
{
return in.getFilePointer();
}
public long getTotalBytes()
{
return in.length();
}
public long getKeyPosition()
{
return keyPosition;
}
}