org.elasticsearch.index.similarity.NonNegativeScoresSimilarity Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* 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.index.similarity;
import org.apache.lucene.index.FieldInvertState;
import org.apache.lucene.search.CollectionStatistics;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.TermStatistics;
import org.apache.lucene.search.similarities.Similarity;
/**
* A {@link Similarity} that rejects negative scores. This class exists so that users get
* an error instead of silently corrupt top hits. It should be applied to any custom or
* scripted similarity.
*/
// public for testing
public final class NonNegativeScoresSimilarity extends Similarity {
// Escape hatch
private static final String ES_ENFORCE_POSITIVE_SCORES = "es.enforce.positive.scores";
private static final boolean ENFORCE_POSITIVE_SCORES;
static {
String enforcePositiveScores = System.getProperty(ES_ENFORCE_POSITIVE_SCORES);
if (enforcePositiveScores == null) {
ENFORCE_POSITIVE_SCORES = true;
} else if ("false".equals(enforcePositiveScores)) {
ENFORCE_POSITIVE_SCORES = false;
} else {
throw new IllegalArgumentException(ES_ENFORCE_POSITIVE_SCORES + " may only be unset or set to [false], but got [" +
enforcePositiveScores + "]");
}
}
private final Similarity in;
public NonNegativeScoresSimilarity(Similarity in) {
this.in = in;
}
public Similarity getDelegate() {
return in;
}
@Override
public long computeNorm(FieldInvertState state) {
return in.computeNorm(state);
}
@Override
public SimScorer scorer(float boost, CollectionStatistics collectionStats, TermStatistics... termStats) {
final SimScorer inScorer = in.scorer(boost, collectionStats, termStats);
return new SimScorer() {
@Override
public float score(float freq, long norm) {
float score = inScorer.score(freq, norm);
if (score < 0f) {
if (ENFORCE_POSITIVE_SCORES) {
throw new IllegalArgumentException("Similarities must not produce negative scores, but got:\n" +
inScorer.explain(Explanation.match(freq, "term frequency"), norm));
} else {
return 0f;
}
}
return score;
}
@Override
public Explanation explain(Explanation freq, long norm) {
Explanation expl = inScorer.explain(freq, norm);
if (expl.isMatch() && expl.getValue().floatValue() < 0) {
expl = Explanation.match(0f, "max of:",
expl, Explanation.match(0f, "Minimum allowed score"));
}
return expl;
}
};
}
}