org.elasticsearch.index.similarity.AbstractSimilarityProvider 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.search.similarities.Normalization;
import org.apache.lucene.search.similarities.NormalizationH1;
import org.apache.lucene.search.similarities.NormalizationH2;
import org.apache.lucene.search.similarities.NormalizationH3;
import org.apache.lucene.search.similarities.NormalizationZ;
import org.elasticsearch.common.settings.Settings;
/**
* Abstract implementation of {@link SimilarityProvider} providing common behaviour
*/
public abstract class AbstractSimilarityProvider implements SimilarityProvider {
protected static final Normalization NO_NORMALIZATION = new Normalization.NoNormalization();
private final String name;
/**
* Creates a new AbstractSimilarityProvider with the given name
*
* @param name Name of the Provider
*/
protected AbstractSimilarityProvider(String name) {
this.name = name;
}
/**
* {@inheritDoc}
*/
@Override
public String name() {
return this.name;
}
/**
* Parses the given Settings and creates the appropriate {@link Normalization}
*
* @param settings Settings to parse
* @return {@link Normalization} referred to in the Settings
*/
protected Normalization parseNormalization(Settings settings) {
String normalization = settings.get("normalization");
if ("no".equals(normalization)) {
return NO_NORMALIZATION;
} else if ("h1".equals(normalization)) {
float c = settings.getAsFloat("normalization.h1.c", 1f);
return new NormalizationH1(c);
} else if ("h2".equals(normalization)) {
float c = settings.getAsFloat("normalization.h2.c", 1f);
return new NormalizationH2(c);
} else if ("h3".equals(normalization)) {
float c = settings.getAsFloat("normalization.h3.c", 800f);
return new NormalizationH3(c);
} else if ("z".equals(normalization)) {
float z = settings.getAsFloat("normalization.z.z", 0.30f);
return new NormalizationZ(z);
} else {
throw new IllegalArgumentException("Unsupported Normalization [" + normalization + "]");
}
}
}