@Override
 public void start() throws Exception {
   FileMetaData metaDatas[] = srm.getFileMetaData(surl_strings);
   if (metaDatas == null || metaDatas.length == 0) {
     throw new Exception("received empty set of FileMetaData");
   }
   for (FileMetaData metaData : metaDatas) {
     System.out.println("FileMetaData(" + metaData.SURL + ")=\n" + metaData.toString());
   }
 }