| /* |
| * 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.aggregation; |
| |
| import com.google.common.primitives.Longs; |
| import org.apache.druid.segment.BaseFloatColumnValueSelector; |
| |
| import java.util.Comparator; |
| |
| public class HistogramAggregator implements Aggregator |
| { |
| static final Comparator COMPARATOR = new Comparator() |
| { |
| @Override |
| public int compare(Object o, Object o1) |
| { |
| return Longs.compare(((Histogram) o).count, ((Histogram) o1).count); |
| } |
| }; |
| |
| static Histogram combineHistograms(Object lhs, Object rhs) |
| { |
| return ((Histogram) lhs).fold((Histogram) rhs); |
| } |
| |
| private final BaseFloatColumnValueSelector selector; |
| |
| private Histogram histogram; |
| |
| public HistogramAggregator(BaseFloatColumnValueSelector selector, float[] breaks) |
| { |
| this.selector = selector; |
| this.histogram = new Histogram(breaks); |
| } |
| |
| @Override |
| public void aggregate() |
| { |
| histogram.offer(selector.getFloat()); |
| } |
| |
| @Override |
| public Object get() |
| { |
| return this.histogram; |
| } |
| |
| @Override |
| public float getFloat() |
| { |
| throw new UnsupportedOperationException("HistogramAggregator does not support getFloat()"); |
| } |
| |
| @Override |
| public long getLong() |
| { |
| throw new UnsupportedOperationException("HistogramAggregator does not support getLong()"); |
| } |
| |
| @Override |
| public double getDouble() |
| { |
| throw new UnsupportedOperationException("HistogramAggregator does not support getDouble()"); |
| } |
| |
| @Override |
| public void close() |
| { |
| // no resources to cleanup |
| } |
| } |