InputStream is = getResource("xml/book/books.dtd");
Reader dtdReader = new InputStreamReader(is);
// create an instance of DTD marshaller
DtdMarshaller marshaller = new DtdMarshaller();
marshaller.addBinding("since", new TypeBinding()
{
public Object unmarshal(String value)
{
// todo: implement unmarshal
throw new UnsupportedOperationException("unmarshal is not implemented.");