private static String getPOS(final AnalyzedTokenReadings atr) {
   final StringBuilder sb = new StringBuilder();
   final int readNum = atr.getReadingsLength();
   for (int i = 0; i < readNum; i++) {
     if (!atr.isWhitespace()) {
       sb.append(atr.getAnalyzedToken(i).getPOSTag());
       if (i != readNum - 1) {
         sb.append('+');
       }
     }
   }
   return sb.toString();
 }