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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.search.aggregations.metrics;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.xcontent.XContentBuilder;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Objects;
public class InternalAvg extends InternalNumericMetricsAggregation.SingleValue implements Avg {
private final double sum;
private final long count;
public InternalAvg(String name, double sum, long count, DocValueFormat format, Map metadata) {
super(name, metadata);
this.sum = sum;
this.count = count;
this.format = format;
}
/**
* Read from a stream.
*/
public InternalAvg(StreamInput in) throws IOException {
super(in);
format = in.readNamedWriteable(DocValueFormat.class);
sum = in.readDouble();
count = in.readVLong();
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
out.writeNamedWriteable(format);
out.writeDouble(sum);
out.writeVLong(count);
}
@Override
public double value() {
return getValue();
}
@Override
public double getValue() {
return sum / count;
}
double getSum() {
return sum;
}
long getCount() {
return count;
}
DocValueFormat getFormatter() {
return format;
}
@Override
public String getWriteableName() {
return AvgAggregationBuilder.NAME;
}
@Override
public InternalAvg reduce(List aggregations, ReduceContext reduceContext) {
CompensatedSum kahanSummation = new CompensatedSum(0, 0);
long count = 0;
// Compute the sum of double values with Kahan summation algorithm which is more
// accurate than naive summation.
for (InternalAggregation aggregation : aggregations) {
InternalAvg avg = (InternalAvg) aggregation;
count += avg.count;
kahanSummation.add(avg.sum);
}
return new InternalAvg(getName(), kahanSummation.value(), count, format, getMetadata());
}
@Override
public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
builder.field(CommonFields.VALUE.getPreferredName(), count != 0 ? getValue() : null);
if (count != 0 && format != DocValueFormat.RAW) {
builder.field(CommonFields.VALUE_AS_STRING.getPreferredName(), format.format(getValue()).toString());
}
return builder;
}
@Override
public int hashCode() {
return Objects.hash(super.hashCode(), sum, count, format.getWriteableName());
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null || getClass() != obj.getClass()) return false;
if (super.equals(obj) == false) return false;
InternalAvg other = (InternalAvg) obj;
return Objects.equals(sum, other.sum)
&& Objects.equals(count, other.count)
&& Objects.equals(format.getWriteableName(), other.format.getWriteableName());
}
}