code: /* LanguageTool, a natural language style checker
   * Copyright (C) 2015 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.en;
  
  import gnu.trove.THashSet;
  import org.languagetool.JLanguageTool;
  
  import java.io.InputStream;
  import java.util.*;
  
  /**
   * Data for {@link AvsAnRule}.
   * Loads exceptions (e.g. "hour" as in "an hour") from external files.
   * 
   * @author Daniel Naber
   * @since 3.0
   */
  final class AvsAnData {
  
    private static final Set<String> requiresA = loadWords("/en/det_a.txt");
    private static final Set<String> requiresAn = loadWords("/en/det_an.txt");
  
    private AvsAnData() {
    }
  
    static Set<String> getWordsRequiringA() {
      return requiresA;
    }
  
    static Set<String> getWordsRequiringAn() {
      return requiresAn;
    }
  
    /**
     * Load words, normalized to lowercase unless starting with '*'.
     */
    private static Set<String> loadWords(String path) {
      Set<String> set = new THashSet<>();
      InputStream stream = JLanguageTool.getDataBroker().getFromRulesDirAsStream(path);
      try (Scanner scanner = new Scanner(stream, "utf-8")) {
        while (scanner.hasNextLine()) {
          String line = scanner.nextLine().trim();
          if (line.isEmpty() || line.charAt(0) == '#') {
            continue;
          }
          if (line.charAt(0) == '*') {
            set.add(line.substring(1));
          } else {
            set.add(line.toLowerCase());
          }
        }
      }
      return Collections.unmodifiableSet(set);
    }
  
  }
  