code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2021 Daniel Naber (http://www.danielnaber.de)
   * 
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
   * USA
   */
  
  package org.languagetool.rules.fr;
  
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.languagetool.rules.AbstractMakeContractionsFilter;
  
  public class MakeContractionsFilter extends AbstractMakeContractionsFilter {
    
    private static final Pattern DE_LE = Pattern.compile("\\bde le\\b", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    private static final Pattern A_LE = Pattern.compile("\\bà le\\b", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    private static final Pattern DE_LES = Pattern.compile("\\bde les\\b", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    private static final Pattern A_LES = Pattern.compile("\\bà les\\b", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
  
    protected String fixContractions(String suggestion) {
      Matcher matcher = DE_LE.matcher(suggestion);
      suggestion = matcher.replaceAll("du");
      matcher = A_LE.matcher(suggestion);
      suggestion = matcher.replaceAll("au");
      matcher = DE_LES.matcher(suggestion);
      suggestion = matcher.replaceAll("des");
      matcher = A_LES.matcher(suggestion);
      suggestion = matcher.replaceAll("aux");
      return suggestion;
    }
  
  }