SumAggregator.java example

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 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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
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package org.elasticsearch.search.aggregations.metrics.sum;

import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.common.lease.Releasables;
import org.elasticsearch.common.util.BigArrays;
import org.elasticsearch.common.util.DoubleArray;
import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.LeafBucketCollector;
import org.elasticsearch.search.aggregations.LeafBucketCollectorBase;
import org.elasticsearch.search.aggregations.metrics.NumericMetricsAggregator;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.support.ValuesSource;
import org.elasticsearch.search.internal.SearchContext;

import java.io.IOException;
import java.util.List;
import java.util.Map;

public class SumAggregator extends NumericMetricsAggregator.SingleValue {

    private final ValuesSource.Numeric valuesSource;
    private final DocValueFormat format;

    private DoubleArray sums;

    SumAggregator(String name, ValuesSource.Numeric valuesSource, DocValueFormat formatter, SearchContext context,
            Aggregator parent, List<PipelineAggregator> pipelineAggregators, Map<String, Object> metaData) throws IOException {
        super(name, context, parent, pipelineAggregators, metaData);
        this.valuesSource = valuesSource;
        this.format = formatter;
        if (valuesSource != null) {
            sums = context.bigArrays().newDoubleArray(1, true);
        }
    }

    @Override
    public boolean needsScores() {
        return valuesSource != null && valuesSource.needsScores();
    }

    @Override
    public LeafBucketCollector getLeafCollector(LeafReaderContext ctx,
            final LeafBucketCollector sub) throws IOException {
        if (valuesSource == null) {
            return LeafBucketCollector.NO_OP_COLLECTOR;
        }
        final BigArrays bigArrays = context.bigArrays();
        final SortedNumericDoubleValues values = valuesSource.doubleValues(ctx);
        return new LeafBucketCollectorBase(sub, values) {
            @Override
            public void collect(int doc, long bucket) throws IOException {
                sums = bigArrays.grow(sums, bucket + 1);
                if (values.advanceExact(doc)) {
                    final int valuesCount = values.docValueCount();
                    double sum = 0;
                    for (int i = 0; i < valuesCount; i++) {
                        sum += values.nextValue();
                    }
                    sums.increment(bucket, sum);
                }
            }
        };
    }

    @Override
    public double metric(long owningBucketOrd) {
        if (valuesSource == null || owningBucketOrd >= sums.size()) {
            return 0.0;
        }
        return sums.get(owningBucketOrd);
    }

    @Override
    public InternalAggregation buildAggregation(long bucket) {
        if (valuesSource == null || bucket >= sums.size()) {
            return buildEmptyAggregation();
        }
        return new InternalSum(name, sums.get(bucket), format, pipelineAggregators(), metaData());
    }

    @Override
    public InternalAggregation buildEmptyAggregation() {
        return new InternalSum(name, 0.0, format, pipelineAggregators(), metaData());
    }

    @Override
    public void doClose() {
        Releasables.close(sums);
    }
}