org.apache.cassandra.index.sai.disk.v1.postings.FilteringPostingList Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of cassandra-all Show documentation
Show all versions of cassandra-all Show documentation
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.
The newest version!
/*
* 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.index.sai.disk.v1.postings;
import java.io.IOException;
import org.apache.cassandra.index.sai.postings.OrdinalPostingList;
import org.apache.cassandra.index.sai.postings.PostingList;
import org.apache.lucene.util.FixedBitSet;
/**
* A wrapper that iterates over a delegate {@link PostingList}, filtering out postings at
* positions that are not present in a provided filter.
*/
public class FilteringPostingList implements PostingList
{
private final FixedBitSet filter;
private final OrdinalPostingList delegate;
private final int cardinality;
private int position = 0;
public FilteringPostingList(FixedBitSet filter, OrdinalPostingList delegate)
{
cardinality = filter.cardinality();
this.filter = filter;
this.delegate = delegate;
}
@Override
public void close()
{
delegate.close();
}
/**
*
* @return the segment row ID of the next match
*/
@Override
public long nextPosting() throws IOException
{
while (true)
{
long segmentRowId = delegate.nextPosting();
if (segmentRowId == PostingList.END_OF_STREAM)
{
return PostingList.END_OF_STREAM;
}
if (filter.get(position++))
{
return segmentRowId;
}
}
}
@Override
public long size()
{
return cardinality;
}
@Override
public long advance(long targetRowID) throws IOException
{
long segmentRowId = delegate.advance(targetRowID);
if (segmentRowId == PostingList.END_OF_STREAM)
{
return PostingList.END_OF_STREAM;
}
// these are always for leaf balanced tree postings so the max is 1024
position = (int)delegate.getOrdinal();
// If the ordinal of the ID we just read satisfies the filter, just return it...
if (filter.get(position - 1))
{
return segmentRowId;
}
// ...but if the ID doesn't satisfy the filter, get the next match.
return nextPosting();
}
}