org.elasticsearch.search.aggregations.bucket.filter.FilterAggregatorFactory Maven / Gradle / Ivy

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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.bucket.filter;

import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.Weight;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.search.aggregations.AggregationInitializationException;
import org.elasticsearch.search.aggregations.Aggregator;
import org.elasticsearch.search.aggregations.AggregatorFactories;
import org.elasticsearch.search.aggregations.AggregatorFactory;
import org.elasticsearch.search.aggregations.CardinalityUpperBound;
import org.elasticsearch.search.aggregations.support.AggregationContext;

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

public class FilterAggregatorFactory extends AggregatorFactory {

    private final Query filter;
    private Weight weight;

    public FilterAggregatorFactory(
        String name,
        QueryBuilder filterBuilder,
        AggregationContext context,
        AggregatorFactory parent,
        AggregatorFactories.Builder subFactoriesBuilder,
        Map metadata
    ) throws IOException {
        super(name, context, parent, subFactoriesBuilder, metadata);
        filter = context.buildQuery(filterBuilder);
    }

    /**
     * Returns the {@link Weight} for this filter aggregation, creating it if
     * necessary. This is done lazily so that the {@link Weight} is only created
     * if the aggregation collects documents reducing the overhead of the
     * aggregation in the case where no documents are collected.
     *
     * Note that as aggregations are initialsed and executed in a serial manner,
     * no concurrency considerations are necessary here.
     */
    public Weight getWeight() {
        if (weight == null) {
            IndexSearcher contextSearcher = context.searcher();
            try {
                weight = contextSearcher.createWeight(contextSearcher.rewrite(filter), ScoreMode.COMPLETE_NO_SCORES, 1f);
            } catch (IOException e) {
                throw new AggregationInitializationException("Failed to initialse filter", e);
            }
        }
        return weight;
    }

    @Override
    public Aggregator createInternal(Aggregator parent, CardinalityUpperBound cardinality, Map metadata)
        throws IOException {
        return new FilterAggregator(name, () -> this.getWeight(), factories, context, parent, cardinality, metadata);
    }

}