| /* |
| * 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.phonetic; |
| |
| import java.io.IOException; |
| import org.apache.commons.codec.Encoder; |
| import org.apache.lucene.analysis.TokenFilter; |
| import org.apache.lucene.analysis.TokenStream; |
| import org.apache.lucene.analysis.tokenattributes.CharTermAttribute; |
| import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute; |
| |
| /** |
| * Create tokens for phonetic matches. |
| * |
| * @see <a |
| * href="http://commons.apache.org/codec/api-release/org/apache/commons/codec/language/package-summary.html"> |
| * Apache Commons Codec</a> |
| */ |
| public final class PhoneticFilter extends TokenFilter { |
| /** true if encoded tokens should be added as synonyms */ |
| protected boolean inject = true; |
| /** phonetic encoder */ |
| protected Encoder encoder = null; |
| /** captured state, non-null when <code>inject=true</code> and a token is buffered */ |
| protected State save = null; |
| |
| private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class); |
| private final PositionIncrementAttribute posAtt = addAttribute(PositionIncrementAttribute.class); |
| |
| /** |
| * Creates a PhoneticFilter with the specified encoder, and either adding encoded forms as |
| * synonyms (<code>inject=true</code>) or replacing them. |
| */ |
| public PhoneticFilter(TokenStream in, Encoder encoder, boolean inject) { |
| super(in); |
| this.encoder = encoder; |
| this.inject = inject; |
| } |
| |
| @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.length() == 0) return true; |
| |
| String value = termAtt.toString(); |
| 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.setEmpty().append(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.setEmpty().append(phonetic); |
| return true; |
| } |
| |
| @Override |
| public void reset() throws IOException { |
| input.reset(); |
| save = null; |
| } |
| } |