/*
* Licensed to Elasticsearch 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.LeafReaderContext;
import org.apache.lucene.search.Explanation;
import java.io.IOException;
import java.util.Objects;
public class WeightFactorFunction extends ScoreFunction {
private static final ScoreFunction SCORE_ONE = new ScoreOne(CombineFunction.MULTIPLY);
private final ScoreFunction scoreFunction;
private float weight = 1.0f;
public WeightFactorFunction(float weight, ScoreFunction scoreFunction) {
super(CombineFunction.MULTIPLY);
if (scoreFunction == null) {
this.scoreFunction = SCORE_ONE;
} else {
this.scoreFunction = scoreFunction;
}
this.weight = weight;
}
public WeightFactorFunction(float weight) {
super(CombineFunction.MULTIPLY);
this.scoreFunction = SCORE_ONE;
this.weight = weight;
}
@Override
public LeafScoreFunction getLeafScoreFunction(LeafReaderContext ctx) throws IOException {
final LeafScoreFunction leafFunction = scoreFunction.getLeafScoreFunction(ctx);
return new LeafScoreFunction() {
@Override
public double score(int docId, float subQueryScore) throws IOException {
return leafFunction.score(docId, subQueryScore) * getWeight();
}
@Override
public Explanation explainScore(int docId, Explanation subQueryScore) throws IOException {
Explanation functionExplanation = leafFunction.explainScore(docId, subQueryScore);
return Explanation.match(
functionExplanation.getValue() * (float) getWeight(), "product of:",
functionExplanation, explainWeight());
}
};
}
@Override
public boolean needsScores() {
return scoreFunction.needsScores();
}
public Explanation explainWeight() {
return Explanation.match(getWeight(), "weight");
}
public float getWeight() {
return weight;
}
public ScoreFunction getScoreFunction() {
return scoreFunction;
}
@Override
protected boolean doEquals(ScoreFunction other) {
WeightFactorFunction weightFactorFunction = (WeightFactorFunction) other;
return this.weight == weightFactorFunction.weight &&
Objects.equals(this.scoreFunction, weightFactorFunction.scoreFunction);
}
@Override
protected int doHashCode() {
return Objects.hash(weight, scoreFunction);
}
private static class ScoreOne extends ScoreFunction {
protected ScoreOne(CombineFunction scoreCombiner) {
super(scoreCombiner);
}
@Override
public LeafScoreFunction getLeafScoreFunction(LeafReaderContext ctx) {
return new LeafScoreFunction() {
@Override
public double score(int docId, float subQueryScore) {
return 1.0;
}
@Override
public Explanation explainScore(int docId, Explanation subQueryScore) {
return Explanation.match(1.0f, "constant score 1.0 - no function provided");
}
};
}
@Override
public boolean needsScores() {
return false;
}
@Override
protected boolean doEquals(ScoreFunction other) {
return true;
}
@Override
protected int doHashCode() {
return 0;
}
}
}