/*
* 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.db.columniterator;
import java.io.IOException;
import org.apache.cassandra.db.ColumnFamily;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.OnDiskAtom;
import org.apache.cassandra.db.RowIndexEntry;
import org.apache.cassandra.db.filter.ColumnSlice;
import org.apache.cassandra.io.sstable.SSTableReader;
import org.apache.cassandra.io.util.FileDataInput;
/**
* A Column Iterator over SSTable
*/
public class SSTableSliceIterator implements ISSTableColumnIterator
{
private final OnDiskAtomIterator reader;
private final DecoratedKey key;
private final SSTableReader sstable;
public SSTableSliceIterator(SSTableReader sstable, DecoratedKey key, ColumnSlice[] slices, boolean reversed)
{
this.sstable = sstable;
this.key = key;
RowIndexEntry indexEntry = sstable.getPosition(key, SSTableReader.Operator.EQ);
this.reader = indexEntry == null ? null : createReader(sstable, indexEntry, null, slices, reversed);
}
/**
* An iterator for a slice within an SSTable
* @param sstable Table for the CFS we are reading from
* @param file Optional parameter that input is read from. If null is passed, this class creates an appropriate one automatically.
* If this class creates, it will close the underlying file when #close() is called.
* If a caller passes a non-null argument, this class will NOT close the underlying file when the iterator is closed (i.e. the caller is responsible for closing the file)
* In all cases the caller should explicitly #close() this iterator.
* @param key The key the requested slice resides under
* @param slices the column slices
* @param reversed Results are returned in reverse order iff reversed is true.
* @param indexEntry position of the row
*/
public SSTableSliceIterator(SSTableReader sstable, FileDataInput file, DecoratedKey key, ColumnSlice[] slices, boolean reversed, RowIndexEntry indexEntry)
{
this.sstable = sstable;
this.key = key;
reader = createReader(sstable, indexEntry, file, slices, reversed);
}
private static OnDiskAtomIterator createReader(SSTableReader sstable, RowIndexEntry indexEntry, FileDataInput file, ColumnSlice[] slices, boolean reversed)
{
return slices.length == 1 && slices[0].start.remaining() == 0 && !reversed
? new SimpleSliceReader(sstable, indexEntry, file, slices[0].finish)
: new IndexedSliceReader(sstable, indexEntry, file, slices, reversed);
}
public SSTableReader getSStable()
{
return sstable;
}
public DecoratedKey getKey()
{
return key;
}
public ColumnFamily getColumnFamily()
{
return reader == null ? null : reader.getColumnFamily();
}
public boolean hasNext()
{
return reader != null && reader.hasNext();
}
public OnDiskAtom next()
{
return reader.next();
}
public void remove()
{
throw new UnsupportedOperationException();
}
public void close() throws IOException
{
if (reader != null)
reader.close();
}
}