Bulk API - Upload documents (files and URL) through CSV

I have tried uploading files through CSV using Bulk API's createBatchWithFileattachment() call. It basically goes like this:

createBatchWithFileAttachments(JobInfo jobInfo, InputStream batchContent, File rootDirectory,
        String... files)

Documents can be either files or the URLs. This particular call is used for uploading files through CSVs. If there is a document that is of the type 'URL', the body field is empty and the call returns FileNotFoundException(). Is there a way that I can create a job that encompasses both files and non-files through Bulk API?

This is with reference for Bulk API class mentioned here:

To import binary attachments, use the following methods. Specify the CSV, XML, or JSON content for the batch in the batchContent parameter, or include request.txt in the attached files and pass null to the batchContent parameter. These methods are contained within the com.async.BulkConnection class:

createBatchFromDir()
createBatchWithFileAttachments()
createBatchWithInputStreamAttachments()
createBatchFromZipStream()

EDIT: Solution is to use the existing method mentioned (Thanks to Daniel). I am able to write a separate utility that does this:

private BatchInfo createBatchFromFiles(JobInfo job, Path fileDir, List<String> paths, Path newCsv)
            throws AsyncApiException, IOException
    {

        Map<String, InputStream> attachments = new HashMap<>();
        for (String path : paths)
        {
            Path filePath = fileDir.resolve(path);
            if (Files.exists(filePath))
                attachments.put(path, Files.newInputStream(filePath));
            else
                attachments.put(path, new ByteArrayInputStream("".getBytes()));
        }

        return ConnectionManager.getBulkConnection().createBatchWithInputStreamAttachments(job,
                Files.newInputStream(newCsv), attachments);
    }

Note that the CSV under the body field should contain the data as "#" for a document and "" (empty string) for a URL.