void getFileTypes(Metadata metadata, Map<Cols, String> output) {
        if (metadata == null) {
            return;
        }
        String type = metadata.get(Metadata.CONTENT_TYPE);
        if (type == null) {
            return;
        }
        int mimeId = writer.getMimeId(type);
        output.put(Cols.MIME_ID, Integer.toString(mimeId));
    }
Checks to see if metadata is null or content is empty (null or only whitespace).
If any of these, then this does no processing, and the fileId is not
entered into the content table.

@param fileId
@param textStats
@param contentsTable
tika-eval/tika-eval-app/src/main/java/org/apache/tika/eval/app/AbstractProfiler.java