org.elasticsearch.common.lucene.search.function.FunctionScoreQuery Maven / Gradle / Ivy
/*
* Licensed to ElasticSearch and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with 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
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.common.lucene.search.function;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.*;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.ToStringUtils;
import java.io.IOException;
import java.util.Set;
/**
* A query that allows for a pluggable boost function to be applied to it.
*/
public class FunctionScoreQuery extends Query {
Query subQuery;
final ScoreFunction function;
public FunctionScoreQuery(Query subQuery, ScoreFunction function) {
this.subQuery = subQuery;
this.function = function;
}
public Query getSubQuery() {
return subQuery;
}
public ScoreFunction getFunction() {
return function;
}
@Override
public Query rewrite(IndexReader reader) throws IOException {
Query newQ = subQuery.rewrite(reader);
if (newQ == subQuery) return this;
FunctionScoreQuery bq = (FunctionScoreQuery) this.clone();
bq.subQuery = newQ;
return bq;
}
@Override
public void extractTerms(Set terms) {
subQuery.extractTerms(terms);
}
@Override
public Weight createWeight(IndexSearcher searcher) throws IOException {
Weight subQueryWeight = subQuery.createWeight(searcher);
return new CustomBoostFactorWeight(subQueryWeight);
}
class CustomBoostFactorWeight extends Weight {
final Weight subQueryWeight;
public CustomBoostFactorWeight(Weight subQueryWeight) throws IOException {
this.subQueryWeight = subQueryWeight;
}
public Query getQuery() {
return FunctionScoreQuery.this;
}
@Override
public float getValueForNormalization() throws IOException {
float sum = subQueryWeight.getValueForNormalization();
sum *= getBoost() * getBoost();
return sum;
}
@Override
public void normalize(float norm, float topLevelBoost) {
subQueryWeight.normalize(norm, topLevelBoost * getBoost());
}
@Override
public Scorer scorer(AtomicReaderContext context, boolean scoreDocsInOrder, boolean topScorer, Bits acceptDocs) throws IOException {
Scorer subQueryScorer = subQueryWeight.scorer(context, scoreDocsInOrder, false, acceptDocs);
if (subQueryScorer == null) {
return null;
}
function.setNextReader(context);
return new CustomBoostFactorScorer(this, subQueryScorer, function);
}
@Override
public Explanation explain(AtomicReaderContext context, int doc) throws IOException {
Explanation subQueryExpl = subQueryWeight.explain(context, doc);
if (!subQueryExpl.isMatch()) {
return subQueryExpl;
}
function.setNextReader(context);
Explanation functionExplanation = function.explainScore(doc, subQueryExpl);
float sc = getBoost() * functionExplanation.getValue();
Explanation res = new ComplexExplanation(true, sc, "custom score, product of:");
res.addDetail(functionExplanation);
res.addDetail(new Explanation(getBoost(), "queryBoost"));
return res;
}
}
static class CustomBoostFactorScorer extends Scorer {
private final float subQueryBoost;
private final Scorer scorer;
private final ScoreFunction function;
private CustomBoostFactorScorer(CustomBoostFactorWeight w, Scorer scorer, ScoreFunction function) throws IOException {
super(w);
this.subQueryBoost = w.getQuery().getBoost();
this.scorer = scorer;
this.function = function;
}
@Override
public int docID() {
return scorer.docID();
}
@Override
public int advance(int target) throws IOException {
return scorer.advance(target);
}
@Override
public int nextDoc() throws IOException {
return scorer.nextDoc();
}
@Override
public float score() throws IOException {
return subQueryBoost * function.score(scorer.docID(), scorer.score());
}
@Override
public int freq() throws IOException {
return scorer.freq();
}
@Override
public long cost() {
return scorer.cost();
}
}
public String toString(String field) {
StringBuilder sb = new StringBuilder();
sb.append("custom score (").append(subQuery.toString(field)).append(",function=").append(function).append(')');
sb.append(ToStringUtils.boost(getBoost()));
return sb.toString();
}
public boolean equals(Object o) {
if (getClass() != o.getClass()) return false;
FunctionScoreQuery other = (FunctionScoreQuery) o;
return this.getBoost() == other.getBoost()
&& this.subQuery.equals(other.subQuery)
&& this.function.equals(other.function);
}
public int hashCode() {
return subQuery.hashCode() + 31 * function.hashCode() ^ Float.floatToIntBits(getBoost());
}
}