public void importRtfDocument(Reader documentSource) throws IOException, DocumentException {
if(!this.open) {
throw new DocumentException("The document must be open to import RTF documents.");
}
RtfParser rtfImport = new RtfParser();
rtfImport.importRtfDocument(documentSource, this.rtfDoc);
}
/**
* Adds a fragment of an RTF document to the current RTF document being generated.
* Since this fragment doesn't contain font or color tables, all fonts and colors