code: private static void showUsage()
      {
  	System.out.println("BatchExtractor <pdf-dir-path> <output-dir-path> <parser>");
  	System.out.println("BatchExtractor <pdf-dir-path> <output-dir-path> <parser> --debug");
  	System.out.println("BatchExtractor <pdf-dir-path> <output-dir-path> <parser> --small");
  	System.out.println("\tparser= pdfbox | tet");
      }
docs: Shows usages by displaying the information on the screen, such as the PDF path, output path, the PDF parser, process mode, etc.