org.apache.lucene.analysis.ngram.EdgeNGramTokenizerFactory Maven / Gradle / Ivy
package org.apache.lucene.analysis.ngram;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*/
import java.io.Reader;
import java.util.Map;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.util.TokenizerFactory;
import org.apache.lucene.util.AttributeFactory;
import org.apache.lucene.util.Version;
/**
* Creates new instances of {@link EdgeNGramTokenizer}.
*
* <fieldType name="text_edgngrm" class="solr.TextField" positionIncrementGap="100">
* <analyzer>
* <tokenizer class="solr.EdgeNGramTokenizerFactory" minGramSize="1" maxGramSize="1"/>
* </analyzer>
* </fieldType>
*/
public class EdgeNGramTokenizerFactory extends TokenizerFactory {
private final int maxGramSize;
private final int minGramSize;
private final String side;
/** Creates a new EdgeNGramTokenizerFactory */
public EdgeNGramTokenizerFactory(Map args) {
super(args);
minGramSize = getInt(args, "minGramSize", EdgeNGramTokenizer.DEFAULT_MIN_GRAM_SIZE);
maxGramSize = getInt(args, "maxGramSize", EdgeNGramTokenizer.DEFAULT_MAX_GRAM_SIZE);
side = get(args, "side", EdgeNGramTokenFilter.Side.FRONT.getLabel());
if (!args.isEmpty()) {
throw new IllegalArgumentException("Unknown parameters: " + args);
}
}
@Override
public Tokenizer create(AttributeFactory factory, Reader input) {
if (luceneMatchVersion.onOrAfter(Version.LUCENE_4_4)) {
if (!EdgeNGramTokenFilter.Side.FRONT.getLabel().equals(side)) {
throw new IllegalArgumentException(EdgeNGramTokenizer.class.getSimpleName() + " does not support backward n-grams as of Lucene 4.4");
}
return new EdgeNGramTokenizer(luceneMatchVersion, input, minGramSize, maxGramSize);
} else {
return new Lucene43EdgeNGramTokenizer(luceneMatchVersion, input, side, minGramSize, maxGramSize);
}
}
}