/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.analysis;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.de.GermanAnalyzer;
import org.apache.lucene.analysis.fr.FrenchAnalyzer;
import org.apache.lucene.analysis.nl.DutchAnalyzer;
import org.apache.lucene.analysis.snowball.SnowballAnalyzer;
import org.elasticsearch.common.collect.ImmutableMap;
import org.elasticsearch.common.collect.ImmutableSet;
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;
import org.elasticsearch.env.Environment;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.settings.IndexSettings;
import java.util.Set;
/**
* Creates a SnowballAnalyzer initialized with stopwords and Snowball filter. Only
* supports Dutch, English (default), French, German and German2 where stopwords
* are readily available. For other languages available with the Lucene Snowball
* Stemmer, use them directly with the SnowballFilter and a CustomAnalyzer.
* Configuration of language is done with the "language" attribute or the analyzer.
* Also supports additional stopwords via "stopwords" attribute
*
* The SnowballAnalyzer comes with a StandardFilter, LowerCaseFilter, StopFilter
* and the SnowballFilter.
*
* @author kimchy (Shay Banon)
* @author harryf (Harry Fuecks)
*/
public class SnowballAnalyzerProvider extends AbstractIndexAnalyzerProvider<SnowballAnalyzer> {
private static final ImmutableMap<String, Set<?>> defaultLanguageStopwords = MapBuilder.<String, Set<?>>newMapBuilder()
.put("English", StopAnalyzer.ENGLISH_STOP_WORDS_SET)
.put("Dutch", DutchAnalyzer.getDefaultStopSet())
.put("German", GermanAnalyzer.getDefaultStopSet())
.put("German2", GermanAnalyzer.getDefaultStopSet())
.put("French", FrenchAnalyzer.getDefaultStopSet())
.immutableMap();
private final SnowballAnalyzer analyzer;
@Inject public SnowballAnalyzerProvider(Index index, @IndexSettings Settings indexSettings, Environment env, @Assisted String name, @Assisted Settings settings) {
super(index, indexSettings, name, settings);
String language = settings.get("language", settings.get("name", "English"));
Set<?> defaultStopwords = defaultLanguageStopwords.containsKey(language) ? defaultLanguageStopwords.get(language) : ImmutableSet.<Set<?>>of();
Set<?> stopWords = Analysis.parseStopWords(env, settings, defaultStopwords);
analyzer = new SnowballAnalyzer(version, language, stopWords);
}
@Override public SnowballAnalyzer get() {
return this.analyzer;
}
}