private void validateInput()

in java/com/google/gerrit/plugins/codeowners/restapi/CheckCodeOwner.java [349:387]
38 lines of code
10 McCabe index (conditional complexity)

  private void validateInput(BranchResource branchResource)
      throws BadRequestException, AuthException, IOException, ConfigInvalidException,
          PermissionBackendException, ResourceNotFoundException {
    if (branchResource.getRevision().isEmpty()) {
      throw new ResourceNotFoundException(IdString.fromDecoded(branchResource.getName()));
    }

    if (email == null) {
      throw new BadRequestException("email required");
    }
    if (path == null) {
      throw new BadRequestException("path required");
    }
    if (user != null) {
      try {
        identifiedUser =
            accountsCollection
                .parse(TopLevelResource.INSTANCE, IdString.fromDecoded(user))
                .getUser();
      } catch (ResourceNotFoundException e) {
        throw new BadRequestException(String.format("user %s not found", user), e);
      }
    }
    if (change != null) {
      Optional<ChangeNotes> changeNotes = changeFinder.findOne(change);
      if (!changeNotes.isPresent()
          || !permissionBackend
              .currentUser()
              .change(changeNotes.get())
              .test(ChangePermission.READ)) {
        throw new BadRequestException(String.format("change %s not found", change));
      }
      if (!changeNotes.get().getChange().getDest().equals(branchResource.getBranchKey())) {
        throw new BadRequestException(
            "target branch of specified change must match branch from the request URL");
      }
      this.changeNotes = changeNotes.get();
    }
  }