AvgBucketPipelineAggregator.java example

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 * the Apache License, Version 2.0 (the "License"); you may
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 * 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.pipeline.bucketmetrics.avg;

import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.search.DocValueFormat;
import org.elasticsearch.search.aggregations.InternalAggregation;
import org.elasticsearch.search.aggregations.pipeline.BucketHelpers.GapPolicy;
import org.elasticsearch.search.aggregations.pipeline.InternalSimpleValue;
import org.elasticsearch.search.aggregations.pipeline.PipelineAggregator;
import org.elasticsearch.search.aggregations.pipeline.bucketmetrics.BucketMetricsPipelineAggregator;

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

public class AvgBucketPipelineAggregator extends BucketMetricsPipelineAggregator {
    private int count = 0;
    private double sum = 0;

    protected AvgBucketPipelineAggregator(String name, String[] bucketsPaths, GapPolicy gapPolicy, DocValueFormat format,
            Map<String, Object> metaData) {
        super(name, bucketsPaths, gapPolicy, format, metaData);
    }

    /**
     * Read from a stream.
     */
    public AvgBucketPipelineAggregator(StreamInput in) throws IOException {
        super(in);
    }

    @Override
    public String getWriteableName() {
        return AvgBucketPipelineAggregationBuilder.NAME;
    }

    @Override
    protected void preCollection() {
        count = 0;
        sum = 0;
    }

    @Override
    protected void collectBucketValue(String bucketKey, Double bucketValue) {
        count++;
        sum += bucketValue;
    }

    @Override
    protected InternalAggregation buildAggregation(List<PipelineAggregator> pipelineAggregators, Map<String, Object> metadata) {
        double avgValue = count == 0 ? Double.NaN : (sum / count);
        return new InternalSimpleValue(name(), avgValue, format, pipelineAggregators, metadata);
    }

}