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 * The ASF 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
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.lucene.queries.function;

import java.io.IOException;
import java.util.Objects;
import java.util.function.DoublePredicate;

import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.ConstantScoreScorer;
import org.apache.lucene.search.ConstantScoreWeight;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.DoubleValues;
import org.apache.lucene.search.DoubleValuesSource;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.QueryVisitor;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.TwoPhaseIterator;
import org.apache.lucene.search.Weight;

A query that retrieves all documents with a DoubleValues value matching a predicate This query works by a linear scan of the index, and is best used in conjunction with other queries that can restrict the number of documents visited
/** * A query that retrieves all documents with a {@link DoubleValues} value matching a predicate * * This query works by a linear scan of the index, and is best used in * conjunction with other queries that can restrict the number of * documents visited */
public final class FunctionMatchQuery extends Query { static final float DEFAULT_MATCH_COST = 100; private final DoubleValuesSource source; private final DoublePredicate filter; private final float matchCost; // not used in equals/hashCode
Create a FunctionMatchQuery with default TwoPhaseIterator matchCost - DEFAULT_MATCH_COST = 100.0
Params:
  • source – a DoubleValuesSource to use for values
  • filter – the predicate to match against
/** * Create a FunctionMatchQuery with default TwoPhaseIterator matchCost - * {@link #DEFAULT_MATCH_COST} = {@value #DEFAULT_MATCH_COST} * @param source a {@link DoubleValuesSource} to use for values * @param filter the predicate to match against */
public FunctionMatchQuery(DoubleValuesSource source, DoublePredicate filter) { this(source, filter, DEFAULT_MATCH_COST); }
Create a FunctionMatchQuery
Params:
/** * Create a FunctionMatchQuery * @param source a {@link DoubleValuesSource} to use for values * @param filter the predicate to match against * @param matchCost to be returned by {@link TwoPhaseIterator#matchCost()} */
public FunctionMatchQuery(DoubleValuesSource source, DoublePredicate filter, float matchCost) { this.source = source; this.filter = filter; this.matchCost = matchCost; } @Override public String toString(String field) { return "FunctionMatchQuery(" + source.toString() + ")"; } @Override public void visit(QueryVisitor visitor) { visitor.visitLeaf(this); } @Override public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException { DoubleValuesSource vs = source.rewrite(searcher); return new ConstantScoreWeight(this, boost) { @Override public Scorer scorer(LeafReaderContext context) throws IOException { DoubleValues values = vs.getValues(context, null); DocIdSetIterator approximation = DocIdSetIterator.all(context.reader().maxDoc()); TwoPhaseIterator twoPhase = new TwoPhaseIterator(approximation) { @Override public boolean matches() throws IOException { return values.advanceExact(approximation.docID()) && filter.test(values.doubleValue()); } @Override public float matchCost() { return matchCost; // TODO maybe DoubleValuesSource should have a matchCost? } }; return new ConstantScoreScorer(this, score(), scoreMode, twoPhase); } @Override public boolean isCacheable(LeafReaderContext ctx) { return source.isCacheable(ctx); } }; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; FunctionMatchQuery that = (FunctionMatchQuery) o; return Objects.equals(source, that.source) && Objects.equals(filter, that.filter); } @Override public int hashCode() { return Objects.hash(source, filter); } }