org.apache.solr.analysis.PhoneticFilter Maven / Gradle / Ivy
/**
* 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.solr.analysis;
import org.apache.commons.codec.Encoder;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.tokenattributes.TermAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import java.io.IOException;
/**
* Create tokens for phonetic matches. See:
* http://jakarta.apache.org/commons/codec/api-release/org/apache/commons/codec/language/package-summary.html
*
* @version $Id: PhoneticFilter.java 804726 2009-08-16 17:28:58Z yonik $
*/
public class PhoneticFilter extends TokenFilter
{
protected boolean inject = true;
protected Encoder encoder = null;
protected String name = null;
protected State save = null;
private final TermAttribute termAtt;
private final PositionIncrementAttribute posAtt;
public PhoneticFilter(TokenStream in, Encoder encoder, String name, boolean inject) {
super(in);
this.encoder = encoder;
this.name = name;
this.inject = inject;
this.termAtt = (TermAttribute) addAttribute(TermAttribute.class);
this.posAtt = (PositionIncrementAttribute) addAttribute(PositionIncrementAttribute.class);
}
@Override
public boolean incrementToken() throws IOException {
if( save != null ) {
// clearAttributes(); // not currently necessary
restoreState(save);
save = null;
return true;
}
if (!input.incrementToken()) return false;
// pass through zero-length terms
if (termAtt.termLength()==0) return true;
String value = termAtt.term();
String phonetic = null;
try {
String v = encoder.encode(value).toString();
if (v.length() > 0 && !value.equals(v)) phonetic = v;
} catch (Exception ignored) {} // just use the direct text
if (phonetic == null) return true;
if (!inject) {
// just modify this token
termAtt.setTermBuffer(phonetic);
return true;
}
// We need to return both the original and the phonetic tokens.
// to avoid a orig=captureState() change_to_phonetic() saved=captureState() restoreState(orig)
// we return the phonetic alternative first
int origOffset = posAtt.getPositionIncrement();
posAtt.setPositionIncrement(0);
save = captureState();
posAtt.setPositionIncrement(origOffset);
termAtt.setTermBuffer(phonetic);
return true;
}
@Override
public void reset() throws IOException {
input.reset();
save = null;
}
}