org.apache.druid.query.rowsandcols.semantic.FramedOnHeapAggregatable Maven / Gradle / Ivy
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/*
* 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.druid.query.rowsandcols.semantic;
import org.apache.druid.query.aggregation.AggregatorFactory;
import org.apache.druid.query.operator.window.WindowFrame;
import org.apache.druid.query.rowsandcols.RowsAndColumns;
import javax.annotation.Nonnull;
/**
* A semantic interface used to aggregate a list of AggregatorFactories across a given set of data
*
* The aggregation specifically happens on-heap and should be used in places where it is known that the data
* set can be worked with entirely on-heap. There is support for frame definitions, frames aggregate certain
* subsets of rows in a rolling fashion like a windowed average. Frames are defined in terms of boundaries
* where a boundary could be based on rows or it could be based on "PEER" groupings.
*
* A peer grouping is defined as a set of rows that are the same based on the ORDER BY columns specified. As such
* peer-grouped values must also come with a set of ORDER BY columns.
*/
public interface FramedOnHeapAggregatable
{
static FramedOnHeapAggregatable fromRAC(RowsAndColumns rac)
{
FramedOnHeapAggregatable retVal = rac.as(FramedOnHeapAggregatable.class);
if (retVal == null) {
retVal = new DefaultFramedOnHeapAggregatable(RowsAndColumns.expectAppendable(rac));
}
return retVal;
}
/**
* Aggregates the data according to the {@link WindowFrame} using the {@code AggregatorFactory} objects provided.
*
* @param frame window frame definition
* @param aggFactories definition of aggregations to be done
* @return a RowsAndColumns that contains columns representing the results of the aggregation
* from the AggregatorFactories
*/
@Nonnull
RowsAndColumns aggregateAll(WindowFrame frame, AggregatorFactory[] aggFactories);
}