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 * 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
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.lucene.analysis.phonetic;

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;

import java.io.IOException;

Create tokens for phonetic matches.
See Also:
/** * 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
/** true if encoded tokens should be added as synonyms */
protected boolean inject = true;
phonetic encoder
/** phonetic encoder */
protected Encoder encoder = null;
captured state, non-null when inject=true and a token is buffered
/** 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 (inject=true) or replacing them.
/** 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; } }