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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.AggregationReduceContext;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.support.SamplingContext;
import org.elasticsearch.xcontent.XContentBuilder;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.Objects;
public class Sum extends InternalNumericMetricsAggregation.SingleValue {
private final double sum;
public Sum(String name, double sum, DocValueFormat formatter, Map metadata) {
super(name, formatter, metadata);
this.sum = sum;
}
/**
* Read from a stream.
*/
public Sum(StreamInput in) throws IOException {
super(in);
sum = in.readDouble();
}
@Override
protected void doWriteTo(StreamOutput out) throws IOException {
out.writeNamedWriteable(format);
out.writeDouble(sum);
}
@Override
public String getWriteableName() {
return SumAggregationBuilder.NAME;
}
@Override
public double value() {
return sum;
}
@Override
public Sum reduce(List aggregations, AggregationReduceContext reduceContext) {
// Compute the sum of double values with Kahan summation algorithm which is more
// accurate than naive summation.
CompensatedSum kahanSummation = new CompensatedSum(0, 0);
for (InternalAggregation aggregation : aggregations) {
double value = ((Sum) aggregation).sum;
kahanSummation.add(value);
}
return new Sum(name, kahanSummation.value(), format, getMetadata());
}
@Override
public InternalAggregation finalizeSampling(SamplingContext samplingContext) {
return new Sum(name, samplingContext.scaleUp(sum), format, getMetadata());
}
@Override
public XContentBuilder doXContentBody(XContentBuilder builder, Params params) throws IOException {
builder.field(CommonFields.VALUE.getPreferredName(), sum);
if (format != DocValueFormat.RAW) {
builder.field(CommonFields.VALUE_AS_STRING.getPreferredName(), format.format(sum).toString());
}
return builder;
}
@Override
public int hashCode() {
return Objects.hash(super.hashCode(), sum);
}
@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;
Sum that = (Sum) obj;
return Objects.equals(sum, that.sum);
}
}