package org.apache.lucene.analysis.icu;
/*
* 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.Arrays;
import java.util.Map;
import org.apache.lucene.analysis.util.AbstractAnalysisFactory;
import org.apache.lucene.analysis.util.CharFilterFactory;
import org.apache.lucene.analysis.util.MultiTermAwareComponent;
import com.ibm.icu.text.FilteredNormalizer2;
import com.ibm.icu.text.Normalizer2;
import com.ibm.icu.text.UnicodeSet;
/**
* Factory for {@link ICUNormalizer2CharFilter}
* <p>
* Supports the following attributes:
* <ul>
* <li>name: A <a href="http://unicode.org/reports/tr15/">Unicode Normalization Form</a>,
* one of 'nfc','nfkc', 'nfkc_cf'. Default is nfkc_cf.
* <li>mode: Either 'compose' or 'decompose'. Default is compose. Use "decompose" with nfc
* or nfkc, to get nfd or nfkd, respectively.
* <li>filter: A {@link UnicodeSet} pattern. Codepoints outside the set are
* always left unchanged. Default is [] (the null set, no filtering).
* </ul>
* @see ICUNormalizer2CharFilter
* @see Normalizer2
* @see FilteredNormalizer2
*/
public class ICUNormalizer2CharFilterFactory extends CharFilterFactory implements MultiTermAwareComponent {
private final Normalizer2 normalizer;
/** Creates a new ICUNormalizer2CharFilterFactory */
public ICUNormalizer2CharFilterFactory(Map<String,String> args) {
super(args);
String name = get(args, "name", "nfkc_cf");
String mode = get(args, "mode", Arrays.asList("compose", "decompose"), "compose");
Normalizer2 normalizer = Normalizer2.getInstance
(null, name, "compose".equals(mode) ? Normalizer2.Mode.COMPOSE : Normalizer2.Mode.DECOMPOSE);
String filter = get(args, "filter");
if (filter != null) {
UnicodeSet set = new UnicodeSet(filter);
if (!set.isEmpty()) {
set.freeze();
normalizer = new FilteredNormalizer2(normalizer, set);
}
}
if (!args.isEmpty()) {
throw new IllegalArgumentException("Unknown parameters: " + args);
}
this.normalizer = normalizer;
}
@Override
public Reader create(Reader input) {
return new ICUNormalizer2CharFilter(input, normalizer);
}
@Override
public AbstractAnalysisFactory getMultiTermComponent() {
return this;
}
}