Regarding validating XML against DTD

Question

hello,
In my project I am receiving xml via HTTP post request
and this XML needs to be validated against a DTD in a remote server.
e.g. assume the xml to be
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE PUSH SYSTEM "http:\\whatever:xx\whatever\sms.dtd">
<PUSH ICP="Partenaire" ADM="UtilisateurChezPartenaire" VERSION="1.0">
</PUSH>
the java code uses Xerces parser
      DOMParser parser = new DOMParser();
      parser.setFeature("http://xml.org/sax/features/validation", true);
      parser.setProperty(
                         "http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation",
                         "http:\\whatever:xx\whatever\sms.dtd"");
      parser.parse("c://localcopy/sms.xml");this Works fine.
But in some case I receive xml file without any !DOCTYPE declaration
(but is still needs to be validated against the same DTD as its mentioned in the business rules)
in such case how can the XML be validated against the DTD.
am I extected to add the
<!DOCTYPE PUSH SYSTEM "http:\\whatever:xx\whatever\sms.dtd">
to every XML via some XSLT script or is there a direct way of
validating a xml that has no DOCTYPE reference to a DTD
(the assumption is the DTD location is known beforehand)

Answer 1

ok, i managed to solve the problem my self, using Transformer makes the job easier.
here is the code for anyone who might run into the same problem.#
     public void whatEver(){
          try{
               DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
               DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
               Document xmlDocument = dBuilder.parse(new FileInputStream("c://a.xml"));
               DOMSource source = new DOMSource(xmlDocument);
               //StringWriter writer = new StringWriter();
               StreamResult result = new StreamResult("c://a.xml");
               TransformerFactory tf = TransformerFactory.newInstance();
               Transformer transformer = tf.newTransformer();
               transformer.setOutputProperty(OutputKeys.DOCTYPE_SYSTEM, "./transformations/Push_Gateway.dtd");
               //TransformerFactory transformerFactory = TransformerFactory.newInstance();
               //Transformer newtransformer = transformerFactory.newTransformer();
               transformer.transform(source, result);
          catch(Exception e){
               e.printStackTrace();
     }the above code reads the a.xml file and adds/removes the DOCTYPE as specified in the transformer.setOutputProperty method and the same xml file is updated, this way different DTD could be referenced by the same xml and validated. this saves the process of adding/removing DOCTYPE via xslt.