001/* 002 * Copyright © 2012, 2013, 2014 Royal Botanic Gardens, Kew. 003 * 004 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: 005 * 006 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. 007 * 008 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 009 */ 010package org.kew.rmf.transformers; 011 012import java.text.Normalizer; 013import java.util.HashMap; 014import java.util.Map; 015import java.util.regex.Pattern; 016 017/** 018 * Removes diacritical marks from letters, intended for dealing with OCR errors 019 * and language-ignorant string comparisons. 020 * <br/> 021 * Converts a string to its normalised form using unicode's NFKD form 022 * (http://unicode.org/reports/tr15/). Translates some non-English letters 023 * to what an English speaker might consider an unaccented letter. 024 */ 025public class NormaliseDiacriticalMarksTransformer implements Transformer { 026 027 /* 028 * See http://www.regular-expressions.info/unicode.html for Unicode character classes. 029 * See also Lucene's ASCIIFoldingFilter, which deals with a far greater range of characters. 030 */ 031 032 private final Pattern accents = Pattern.compile("[\\p{M}]"); 033 034 private final Map<String,String> additionalReplacements; 035 public NormaliseDiacriticalMarksTransformer() { 036 additionalReplacements = new HashMap<>(); 037 additionalReplacements.put("Æ", "AE"); 038 additionalReplacements.put("æ", "ae"); 039 additionalReplacements.put("Œ", "OE"); 040 additionalReplacements.put("œ", "oe"); 041 additionalReplacements.put("Ø", "O"); 042 additionalReplacements.put("ø", "o"); 043 additionalReplacements.put("Ł", "L"); 044 additionalReplacements.put("ł", "l"); 045 additionalReplacements.put("Đ", "D"); 046 additionalReplacements.put("đ", "d"); 047 additionalReplacements.put("—", "-"); // emdash to hyphen 048 additionalReplacements.put("–", "-"); // ndash to hyphen 049 }; 050 051 @Override 052 public String transform(String s) { 053 s = Normalizer.normalize(s, Normalizer.Form.NFKD); 054 for (String key : additionalReplacements.keySet()) { 055 s = s.replace(key, additionalReplacements.get(key)); 056 } 057 return accents.matcher(s).replaceAll(""); 058 } 059}