/*
* 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.
*/
package org.apache.lucene.analysis.commongrams;
import java.io.IOException;
import java.util.Map;
import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.core.StopAnalyzer;
import org.apache.lucene.analysis.util.*;
/**
* Constructs a {@link CommonGramsFilter}.
* <pre class="prettyprint">
* <fieldType name="text_cmmngrms" class="solr.TextField" positionIncrementGap="100">
* <analyzer>
* <tokenizer class="solr.WhitespaceTokenizerFactory"/>
* <filter class="solr.CommonGramsFilterFactory" words="commongramsstopwords.txt" ignoreCase="false"/>
* </analyzer>
* </fieldType></pre>
*/
public class CommonGramsFilterFactory extends TokenFilterFactory implements ResourceLoaderAware {
// TODO: shared base class for Stop/Keep/CommonGrams?
private CharArraySet commonWords;
private final String commonWordFiles;
private final String format;
private final boolean ignoreCase;
/** Creates a new CommonGramsFilterFactory */
public CommonGramsFilterFactory(Map<String,String> args) {
super(args);
commonWordFiles = get(args, "words");
format = get(args, "format");
ignoreCase = getBoolean(args, "ignoreCase", false);
if (!args.isEmpty()) {
throw new IllegalArgumentException("Unknown parameters: " + args);
}
}
@Override
public void inform(ResourceLoader loader) throws IOException {
if (commonWordFiles != null) {
if ("snowball".equalsIgnoreCase(format)) {
commonWords = getSnowballWordSet(loader, commonWordFiles, ignoreCase);
} else {
commonWords = getWordSet(loader, commonWordFiles, ignoreCase);
}
} else {
commonWords = StopAnalyzer.ENGLISH_STOP_WORDS_SET;
}
}
public boolean isIgnoreCase() {
return ignoreCase;
}
public CharArraySet getCommonWords() {
return commonWords;
}
@Override
public TokenFilter create(TokenStream input) {
CommonGramsFilter commonGrams = new CommonGramsFilter(input, commonWords);
return commonGrams;
}
}