code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2013 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.tools;
  
  import org.jetbrains.annotations.Nullable;
  
  import java.io.InputStream;
  import java.util.*;
  
  /**
   * A very simple property-style configuration. If a key occurs more than once, the
   * values will be merged to a list with the other properties of that key. This
   * is useful if property files get merged by Maven.
   * 
   * Note: this is not a full replacement for {@link Properties}, e.g. it does
   * not support values that span multiple lines
   */
  public class MultiKeyProperties {
  
    private final Map<String, List<String>> properties = new HashMap<>();
  
    public MultiKeyProperties(InputStream inStream) {
      try (Scanner scanner = new Scanner(inStream)) {
        while (scanner.hasNextLine()) {
          String line = scanner.nextLine().trim();
          if (line.startsWith("#") || line.isEmpty()) {
            continue;
          }
          String[] parts = line.split("\\s*=\\s*");
          if (parts.length != 2) {
            continue;
          }
          String key = parts[0];
          String value = parts[1];
          List<String> list = properties.get(key);
          if (list == null) {
            list = new ArrayList<>();
          }
          list.add(value);
          properties.put(key, list);
        }
      }
    }
  
    /**
     * @return a list of values or {@code null} if there's no such key
     */
    @Nullable
    public List<String> getProperty(String key) {
      return properties.get(key);
    }
  
  }
  