code: final void _deleteWALFileAfterProcessing (@Nonnull @Nonempty final String sWALFilename)
    {
      ValueEnforcer.notEmpty (sWALFilename, "WALFilename");
      final File aWALFile = m_aIO.getFile (sWALFilename);
      if (FileOperationManager.INSTANCE.deleteFile (aWALFile).isFailure ())
      {
        if (LOGGER.isErrorEnabled ())
          LOGGER.error ("Failed to delete WAL file '" + aWALFile.getAbsolutePath () + "'");
      }
      else
      {
        if (!isSilentMode ())
          if (LOGGER.isInfoEnabled ())
            LOGGER.info ("Deleted successfully imported WAL file '" + aWALFile.getAbsolutePath () + "'");
      }
    }
docs: This method may only be triggered with valid WAL filenames, as the passed
  file is deleted!