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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.valuecount;
import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.common.lease.Releasables;
import org.elasticsearch.common.util.BigArrays;
import org.elasticsearch.common.util.LongArray;
import org.elasticsearch.index.fielddata.SortedBinaryDocValues;
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;
/**
* A field data based aggregator that counts the number of values a specific field has within the aggregation context.
*
* This aggregator works in a multi-bucket mode, that is, when serves as a sub-aggregator, a single aggregator instance aggregates the
* counts for all buckets owned by the parent aggregator)
*/
public class ValueCountAggregator extends NumericMetricsAggregator.SingleValue {
final ValuesSource valuesSource;
// a count per bucket
LongArray counts;
public ValueCountAggregator(String name, ValuesSource valuesSource,
SearchContext aggregationContext, Aggregator parent, List<PipelineAggregator> pipelineAggregators,
Map<String, Object> metaData)
throws IOException {
super(name, aggregationContext, parent, pipelineAggregators, metaData);
this.valuesSource = valuesSource;
if (valuesSource != null) {
counts = context.bigArrays().newLongArray(1, true);
}
}
@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 SortedBinaryDocValues values = valuesSource.bytesValues(ctx);
return new LeafBucketCollectorBase(sub, values) {
@Override
public void collect(int doc, long bucket) throws IOException {
counts = bigArrays.grow(counts, bucket + 1);
if (values.advanceExact(doc)) {
counts.increment(bucket, values.docValueCount());
}
}
};
}
@Override
public double metric(long owningBucketOrd) {
return valuesSource == null ? 0 : counts.get(owningBucketOrd);
}
@Override
public InternalAggregation buildAggregation(long bucket) {
if (valuesSource == null || bucket >= counts.size()) {
return buildEmptyAggregation();
}
return new InternalValueCount(name, counts.get(bucket), pipelineAggregators(), metaData());
}
@Override
public InternalAggregation buildEmptyAggregation() {
return new InternalValueCount(name, 0L, pipelineAggregators(), metaData());
}
@Override
public void doClose() {
Releasables.close(counts);
}
}