code: /* LanguageTool, a natural language style checker 
   * Copyright (C) 2014 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;
  
  /**
   * Helper class to create error examples. For internal use by LanguageTool only.
   * @since 2.5
   */
  public final class Example {
  
    private Example() {
    }
  
    /**
     * Create an example text (usually just one sentence) with an error - the error must be marked with {@code <marker>...</marker>}.
     * @throws IllegalArgumentException if the {@code <marker>...</marker>} is missing
     * @since 2.5
     */
    public static IncorrectExample wrong(String example) {
      requireMarkup(example);
      return new IncorrectExample(example);
    }
  
    /**
     * Create an example text (usually just one sentence) without an error - the fixed error (compared to the text created
     * with {@link #wrong(String)}) can be marked with {@code <marker>...</marker>}.
     * @since 2.5, return type modified in 3.5
     */
    public static CorrectExample fixed(String example) {
      return new CorrectExample(example);
    }
  
    private static void requireMarkup(String example) {
      if (!example.contains("<marker>") || !example.contains("</marker>")) {
        throw new IllegalArgumentException("Example text must contain '<marker>...</marker>': " + example);
      }
    }
  
  }
  