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Lucene example source code file (ISOLatin1AccentFilter.java)

This example Lucene source code file (ISOLatin1AccentFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

a, a, c, d, deprecated, e, e, i, i, isolatin1accentfilter, isolatin1accentfilter, o, t, y

The Lucene ISOLatin1AccentFilter.java source code

package org.apache.lucene.analysis;

/**
 * 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 org.apache.lucene.analysis.tokenattributes.CharTermAttribute;

/**
 * A filter that replaces accented characters in the ISO Latin 1 character set 
 * (ISO-8859-1) by their unaccented equivalent. The case will not be altered.
 * <p>
 * For instance, 'à' will be replaced by 'a'.
 * <p>
 * 
 * @deprecated If you build a new index, use {@link ASCIIFoldingFilter}
 * which covers a superset of Latin 1.
 * This class is included for use with existing
 * indexes and will be removed in a future release (possibly Lucene 4.0).
 */
@Deprecated
public final class ISOLatin1AccentFilter extends TokenFilter {
  public ISOLatin1AccentFilter(TokenStream input) {
    super(input);
  }

  private char[] output = new char[256];
  private int outputPos;
  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    
  @Override
  public final boolean incrementToken() throws java.io.IOException {    
    if (input.incrementToken()) {
      final char[] buffer = termAtt.buffer();
      final int length = termAtt.length();
      // If no characters actually require rewriting then we
      // just return token as-is:
      for(int i=0;i<length;i++) {
        final char c = buffer[i];
        if (c >= '\u00c0' && c <= '\uFB06') {
          removeAccents(buffer, length);
          termAtt.copyBuffer(output, 0, outputPos);
          break;
        }
      }
      return true;
    } else
      return false;
  }

  /**
   * To replace accented characters in a String by unaccented equivalents.
   */
  public final void removeAccents(char[] input, int length) {

    // Worst-case length required:
    final int maxSizeNeeded = 2*length;

    int size = output.length;
    while (size < maxSizeNeeded)
      size *= 2;

    if (size != output.length)
      output = new char[size];

    outputPos = 0;

    int pos = 0;

    for (int i=0; i<length; i++, pos++) {
      final char c = input[pos];

      // Quick test: if it's not in range then just keep
      // current character
      if (c < '\u00c0' || c > '\uFB06')
        output[outputPos++] = c;
      else {
        switch (c) {
        case '\u00C0' : // À
        case '\u00C1' : // Á
        case '\u00C2' : // Â
        case '\u00C3' : // Ã
        case '\u00C4' : // Ä
        case '\u00C5' : // Å
          output[outputPos++] = 'A';
          break;
        case '\u00C6' : // Æ
          output[outputPos++] = 'A';
          output[outputPos++] = 'E';
          break;
        case '\u00C7' : // Ç
          output[outputPos++] = 'C';
          break;
        case '\u00C8' : // È
        case '\u00C9' : // É
        case '\u00CA' : // Ê
        case '\u00CB' : // Ë
          output[outputPos++] = 'E';
          break;
        case '\u00CC' : // Ì
        case '\u00CD' : // Í
        case '\u00CE' : // Î
        case '\u00CF' : // Ï
          output[outputPos++] = 'I';
          break;
        case '\u0132' : // IJ
            output[outputPos++] = 'I';
            output[outputPos++] = 'J';
            break;
        case '\u00D0' : // Ð
          output[outputPos++] = 'D';
          break;
        case '\u00D1' : // Ñ
          output[outputPos++] = 'N';
          break;
        case '\u00D2' : // Ò
        case '\u00D3' : // Ó
        case '\u00D4' : // Ô
        case '\u00D5' : // Õ
        case '\u00D6' : // Ö
        case '\u00D8' : // Ø
          output[outputPos++] = 'O';
          break;
        case '\u0152' : // Œ
          output[outputPos++] = 'O';
          output[outputPos++] = 'E';
          break;
        case '\u00DE' : // Þ
          output[outputPos++] = 'T';
          output[outputPos++] = 'H';
          break;
        case '\u00D9' : // Ù
        case '\u00DA' : // Ú
        case '\u00DB' : // Û
        case '\u00DC' : // Ü
          output[outputPos++] = 'U';
          break;
        case '\u00DD' : // Ý
        case '\u0178' : // Ÿ
          output[outputPos++] = 'Y';
          break;
        case '\u00E0' : // à
        case '\u00E1' : // á
        case '\u00E2' : // â
        case '\u00E3' : // ã
        case '\u00E4' : // ä
        case '\u00E5' : // å
          output[outputPos++] = 'a';
          break;
        case '\u00E6' : // æ
          output[outputPos++] = 'a';
          output[outputPos++] = 'e';
          break;
        case '\u00E7' : // ç
          output[outputPos++] = 'c';
          break;
        case '\u00E8' : // è
        case '\u00E9' : // é
        case '\u00EA' : // ê
        case '\u00EB' : // ë
          output[outputPos++] = 'e';
          break;
        case '\u00EC' : // ì
        case '\u00ED' : // í
        case '\u00EE' : // î
        case '\u00EF' : // ï
          output[outputPos++] = 'i';
          break;
        case '\u0133' : // ij
            output[outputPos++] = 'i';
            output[outputPos++] = 'j';
            break;
        case '\u00F0' : // ð
          output[outputPos++] = 'd';
          break;
        case '\u00F1' : // ñ
          output[outputPos++] = 'n';
          break;
        case '\u00F2' : // ò
        case '\u00F3' : // ó
        case '\u00F4' : // ô
        case '\u00F5' : // õ
        case '\u00F6' : // ö
        case '\u00F8' : // ø
          output[outputPos++] = 'o';
          break;
        case '\u0153' : // œ
          output[outputPos++] = 'o';
          output[outputPos++] = 'e';
          break;
        case '\u00DF' : // ß
          output[outputPos++] = 's';
          output[outputPos++] = 's';
          break;
        case '\u00FE' : // þ
          output[outputPos++] = 't';
          output[outputPos++] = 'h';
          break;
        case '\u00F9' : // ù
        case '\u00FA' : // ú
        case '\u00FB' : // û
        case '\u00FC' : // ü
          output[outputPos++] = 'u';
          break;
        case '\u00FD' : // ý
        case '\u00FF' : // ÿ
          output[outputPos++] = 'y';
          break;
        case '\uFB00': // ff
            output[outputPos++] = 'f';
            output[outputPos++] = 'f';
            break;
        case '\uFB01': // fi
            output[outputPos++] = 'f';
            output[outputPos++] = 'i';
            break;
        case '\uFB02': // fl
            output[outputPos++] = 'f';
            output[outputPos++] = 'l';
            break;
        // following 2 are commented as they can break the maxSizeNeeded (and doing *3 could be expensive)
//        case '\uFB03': // ffi
//            output[outputPos++] = 'f';
//            output[outputPos++] = 'f';
//            output[outputPos++] = 'i';
//            break;
//        case '\uFB04': // ffl
//            output[outputPos++] = 'f';
//            output[outputPos++] = 'f';
//            output[outputPos++] = 'l';
//            break;
        case '\uFB05': // ſt
            output[outputPos++] = 'f';
            output[outputPos++] = 't';
            break;
        case '\uFB06': // st
            output[outputPos++] = 's';
            output[outputPos++] = 't';
          break;
        default :
          output[outputPos++] = c;
          break;
        }
      }
    }
  }
}

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