org.elasticsearch.index.similarity.IBSimilarityProvider Maven / Gradle / Ivy
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* the Apache License, Version 2.0 (the "License"); you may
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.elasticsearch.index.similarity;
import com.google.common.collect.ImmutableMap;
import org.apache.lucene.search.similarities.*;
import org.elasticsearch.ElasticsearchIllegalArgumentException;
import org.elasticsearch.common.collect.MapBuilder;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.inject.assistedinject.Assisted;
import org.elasticsearch.common.settings.Settings;
/**
* {@link SimilarityProvider} for {@link IBSimilarity}.
*
* Configuration options available:
*
* - distribution
* - lambda
* - normalization
*
* @see IBSimilarity For more information about configuration
*/
public class IBSimilarityProvider extends AbstractSimilarityProvider {
private static final ImmutableMap DISTRIBUTION_CACHE;
private static final ImmutableMap LAMBDA_CACHE;
static {
MapBuilder distributions = MapBuilder.newMapBuilder();
distributions.put("ll", new DistributionLL());
distributions.put("spl", new DistributionSPL());
DISTRIBUTION_CACHE = distributions.immutableMap();
MapBuilder lamdas = MapBuilder.newMapBuilder();
lamdas.put("df", new LambdaDF());
lamdas.put("ttf", new LambdaTTF());
LAMBDA_CACHE = lamdas.immutableMap();
}
private final IBSimilarity similarity;
@Inject
public IBSimilarityProvider(@Assisted String name, @Assisted Settings settings) {
super(name);
Distribution distribution = parseDistribution(settings);
Lambda lambda = parseLambda(settings);
Normalization normalization = parseNormalization(settings);
this.similarity = new IBSimilarity(distribution, lambda, normalization);
}
/**
* Parses the given Settings and creates the appropriate {@link Distribution}
*
* @param settings Settings to parse
* @return {@link Normalization} referred to in the Settings
*/
protected Distribution parseDistribution(Settings settings) {
String rawDistribution = settings.get("distribution");
Distribution distribution = DISTRIBUTION_CACHE.get(rawDistribution);
if (distribution == null) {
throw new ElasticsearchIllegalArgumentException("Unsupported Distribution [" + rawDistribution + "]");
}
return distribution;
}
/**
* Parses the given Settings and creates the appropriate {@link Lambda}
*
* @param settings Settings to parse
* @return {@link Normalization} referred to in the Settings
*/
protected Lambda parseLambda(Settings settings) {
String rawLambda = settings.get("lambda");
Lambda lambda = LAMBDA_CACHE.get(rawLambda);
if (lambda == null) {
throw new ElasticsearchIllegalArgumentException("Unsupported Lambda [" + rawLambda + "]");
}
return lambda;
}
/**
* {@inheritDoc}
*/
@Override
public Similarity get() {
return similarity;
}
}