descriptionSpellChecker.indexDictionary(descriptionDictionary);
// 4. Create author spellIndex
Directory authorSpellIndexDirectory = FSDirectory.open(new File(spellDictionaryPath + AUTHOR_PATH));//true
SpellChecker authorSpellChecker = new SpellChecker(authorSpellIndexDirectory);
Dictionary authorDictionary = new LuceneDictionary(indexReader, OlatDocument.AUTHOR_FIELD_NAME);
authorSpellChecker.indexDictionary(authorDictionary);
// Merge all part spell indexes (content,title etc.) to one common spell index
Directory spellIndexDirectory = FSDirectory.open(spellDictionaryFile);//true
IndexWriter merger = new IndexWriter(spellIndexDirectory, new StandardAnalyzer(Version.LUCENE_CURRENT), true, IndexWriter.MaxFieldLength.UNLIMITED);
Directory[] directories = { contentSpellIndexDirectory, titleSpellIndexDirectory, descriptionSpellIndexDirectory, authorSpellIndexDirectory};