Review

class PdfWriter {
    public static PdfWriter getInstance(final Document document, final OutputStream os, final DocListener listener)
    throws DocumentException {
        PdfDocument pdf = new PdfDocument();
        pdf.addDocListener(listener);
        document.addDocListener(pdf);
        PdfWriter writer = new PdfWriter(pdf, os);
        pdf.addWriter(writer);
        return writer;
    }

}