@Override
  public ValidationResult validate(File toDir) throws IOException {
    File fromFile = getSource(toDir);
    ValidationResult result = doValidateAccess(fromFile, ValidationResult.Action.UPDATE, true);
    if (result != null) return result;
    if (!mySource.isEmpty()) {
      result = doValidateAccess(getFile(toDir), ValidationResult.Action.UPDATE, true);
      if (result != null) return result;
    }
    return doValidateNotChanged(fromFile, ValidationResult.Action.UPDATE);
  }
@Override
  public ValidationResult validate(File toDir)