io.druid.query.aggregation.hyperloglog.HyperUniquesBufferAggregator Maven / Gradle / Ivy
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* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets 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 io.druid.query.aggregation.hyperloglog;
import io.druid.hll.HyperLogLogCollector;
import io.druid.query.aggregation.BufferAggregator;
import io.druid.query.monomorphicprocessing.RuntimeShapeInspector;
import io.druid.segment.ObjectColumnSelector;
import java.nio.ByteBuffer;
/**
*/
public class HyperUniquesBufferAggregator implements BufferAggregator
{
private static final byte[] EMPTY_BYTES = HyperLogLogCollector.makeEmptyVersionedByteArray();
private final ObjectColumnSelector selector;
public HyperUniquesBufferAggregator(
ObjectColumnSelector selector
)
{
this.selector = selector;
}
@Override
public void init(ByteBuffer buf, int position)
{
final ByteBuffer mutationBuffer = buf.duplicate();
mutationBuffer.position(position);
mutationBuffer.put(EMPTY_BYTES);
}
@Override
public void aggregate(ByteBuffer buf, int position)
{
HyperLogLogCollector collector = (HyperLogLogCollector) selector.getObject();
if (collector == null) {
return;
}
// Save position, limit and restore later instead of allocating a new ByteBuffer object
final int oldPosition = buf.position();
final int oldLimit = buf.limit();
buf.limit(position + HyperLogLogCollector.getLatestNumBytesForDenseStorage());
buf.position(position);
try {
HyperLogLogCollector.makeCollector(buf).fold(collector);
}
finally {
buf.limit(oldLimit);
buf.position(oldPosition);
}
}
@Override
public Object get(ByteBuffer buf, int position)
{
final int size = HyperLogLogCollector.getLatestNumBytesForDenseStorage();
ByteBuffer dataCopyBuffer = ByteBuffer.allocate(size);
ByteBuffer mutationBuffer = buf.duplicate();
mutationBuffer.position(position);
mutationBuffer.limit(position + size);
dataCopyBuffer.put(mutationBuffer);
dataCopyBuffer.rewind();
return HyperLogLogCollector.makeCollector(dataCopyBuffer);
}
@Override
public float getFloat(ByteBuffer buf, int position)
{
throw new UnsupportedOperationException("HyperUniquesBufferAggregator does not support getFloat()");
}
@Override
public long getLong(ByteBuffer buf, int position)
{
throw new UnsupportedOperationException("HyperUniquesBufferAggregator does not support getLong()");
}
@Override
public double getDouble(ByteBuffer buf, int position)
{
throw new UnsupportedOperationException("HyperUniquesBufferAggregator does not support getDouble()");
}
@Override
public void close()
{
// no resources to cleanup
}
@Override
public void inspectRuntimeShape(RuntimeShapeInspector inspector)
{
inspector.visit("selector", selector);
}
}