text: /*
   * 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.histogram;
  
  import com.fasterxml.jackson.annotation.JsonCreator;
  import com.fasterxml.jackson.annotation.JsonProperty;
  import com.fasterxml.jackson.annotation.JsonTypeName;
  import com.google.common.collect.Sets;
  import org.apache.druid.java.util.common.IAE;
  import org.apache.druid.java.util.common.ISE;
  import org.apache.druid.query.aggregation.AggregatorFactory;
  import org.apache.druid.query.aggregation.PostAggregator;
  import org.apache.druid.query.aggregation.post.PostAggregatorIds;
  import org.apache.druid.query.cache.CacheKeyBuilder;
  import org.apache.druid.segment.column.ValueType;
  
  import java.util.Arrays;
  import java.util.Comparator;
  import java.util.Map;
  import java.util.Set;
  
  @JsonTypeName("quantiles")
  public class QuantilesPostAggregator extends ApproximateHistogramPostAggregator
  {
    private final float[] probabilities;
  
    @JsonCreator
    public QuantilesPostAggregator(
        @JsonProperty("name") String name,
        @JsonProperty("fieldName") String fieldName,
        @JsonProperty("probabilities") float[] probabilities
    )
    {
      super(name, fieldName);
      this.probabilities = probabilities;
  
      for (float p : probabilities) {
        if (p < 0 || p > 1) {
          throw new IAE("Illegal probability[%s], must be strictly between 0 and 1", p);
        }
      }
    }
  
    @Override
    public Comparator getComparator()
    {
      throw new UnsupportedOperationException();
    }
  
    @Override
    public Set<String> getDependentFields()
    {
      return Sets.newHashSet(fieldName);
    }
  
    @Override
    public Object compute(Map<String, Object> values)
    {
      Object val = values.get(fieldName);
      if (val instanceof ApproximateHistogram) {
        final ApproximateHistogram ah = (ApproximateHistogram) val;
        return new Quantiles(probabilities, ah.getQuantiles(probabilities), ah.getMin(), ah.getMax());
      } else if (val instanceof FixedBucketsHistogram) {
        final FixedBucketsHistogram fbh = (FixedBucketsHistogram) val;
        double[] adjustedProbabilites = new double[probabilities.length];
        for (int i = 0; i < probabilities.length; i++) {
          adjustedProbabilites[i] = probabilities[i] * 100.0;
        }
        return new Quantiles(
            probabilities,
            fbh.percentilesFloat(adjustedProbabilites),
            (float) fbh.getMin(),
            (float) fbh.getMax()
        );
      }
      throw new ISE("Unknown value type: " + val.getClass());
    }
  
    /**
     * actual type is {@link Quantiles}
     */
    @Override
    public ValueType getType()
    {
      return ValueType.COMPLEX;
    }
  
    @Override
    public PostAggregator decorate(Map<String, AggregatorFactory> aggregators)
    {
      return this;
    }
  
    @JsonProperty
    public float[] getProbabilities()
    {
      return probabilities;
    }
  
    @Override
    public String toString()
    {
      return "QuantilesPostAggregator{" +
             "name='" + name + '\'' +
             ", fieldName='" + fieldName + '\'' +
             ", probabilities=" + Arrays.toString(this.getProbabilities()) +
             '}';
    }
  
    @Override
    public byte[] getCacheKey()
    {
      return new CacheKeyBuilder(PostAggregatorIds.HISTOGRAM_QUANTILES)
          .appendString(fieldName)
          .appendFloatArray(probabilities)
          .build();
    }
  
    @Override
    public boolean equals(Object o)
    {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
      if (!super.equals(o)) {
        return false;
      }
      QuantilesPostAggregator that = (QuantilesPostAggregator) o;
      return Arrays.equals(probabilities, that.probabilities);
    }
  
    @Override
    public int hashCode()
    {
      int result = super.hashCode();
      result = 31 * result + Arrays.hashCode(probabilities);
      return result;
    }
  }
  