org.apache.cassandra.index.sai.disk.v1.bbtree.BlockBalancedTreeIterator Maven / Gradle / Ivy
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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.index.sai.disk.v1.bbtree;
import java.util.Iterator;
import java.util.Map;
import org.apache.cassandra.index.sai.postings.PostingList;
import org.apache.cassandra.index.sai.utils.IndexTermType;
import org.apache.cassandra.index.sai.utils.TermsIterator;
import org.apache.cassandra.utils.Pair;
import org.apache.cassandra.utils.bytecomparable.ByteComparable;
import org.apache.cassandra.utils.bytecomparable.ByteSourceInverse;
import org.apache.lucene.util.packed.PackedLongValues;
/**
* A helper class for mapping disparate iterators to a single iterator for consumption by the
* {@link BlockBalancedTreeWriter}
*/
public interface BlockBalancedTreeIterator extends Iterator>
{
static BlockBalancedTreeIterator fromTermsIterator(final TermsIterator termsIterator, IndexTermType indexTermType)
{
return new BlockBalancedTreeIterator()
{
final byte[] scratch = new byte[indexTermType.fixedSizeOf()];
@Override
public boolean hasNext()
{
return termsIterator.hasNext();
}
@Override
public Pair next()
{
ByteComparable term = termsIterator.next();
ByteSourceInverse.copyBytes(term.asComparableBytes(ByteComparable.Version.OSS50), scratch);
return Pair.create(scratch, termsIterator.postings());
}
};
}
static BlockBalancedTreeIterator fromTrieIterator(Iterator> iterator, int bytesPerValue)
{
return new BlockBalancedTreeIterator()
{
final byte[] scratch = new byte[bytesPerValue];
@Override
public boolean hasNext()
{
return iterator.hasNext();
}
@Override
public Pair next()
{
Map.Entry entry = iterator.next();
ByteSourceInverse.copyBytes(entry.getKey().asComparableBytes(ByteComparable.Version.OSS50), scratch);
PackedLongValues postings = entry.getValue().build();
PackedLongValues.Iterator postingsIterator = postings.iterator();
return Pair.create(scratch, new PostingList() {
@Override
public long nextPosting()
{
if (postingsIterator.hasNext())
return postingsIterator.next();
return END_OF_STREAM;
}
@Override
public long size()
{
return postings.size();
}
@Override
public long advance(long targetRowID)
{
throw new UnsupportedOperationException();
}
});
}
};
}
}