Validating against a DTD specified externally

Question

Hi all,
I don't know if this is possible (well anything is possible):
I would like to validate an XML file from a DTD that I specify. The problem that I have is that the XML is generated by an external system and it can be deployed either on a unix or windows architecture.
I load the XML from file located on either architecture and I want to control the location on either system where the DTD is kept and if possible tell the validator what DTD to use. I am having problems using relative paths when specifying the DTD in the XML and the company doesn't want to use an external public URI.
I am using Java 1.4 and SAX 2.0 . Any pointers or help would be very much appreciated [code is even better ;-)]

Answer 1

Hi,
I cant seem to make the EntityResolver work properly. I was tasked to validate a lot of XML files but they do not have a DOCTYPE entity because the location of the dtd is configurable.
i have stripped down the xml to only contain the root for brevity of testing but i am still stuck. the xml is this:
<?xml version="1.0" encoding="utf-8"?>
<ngui full="f" r="f">
</ngui>and my validation code is this
public class SimpleXMLValidator {
  public boolean validate(String xmlFilePath, String schemaFilePath){
        boolean validXML = true;
        System.setProperty("javax.xml.parsers.DocumentBuilderFactory",
                           "org.apache.xerces.jaxp.DocumentBuilderFactoryImpl");
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);
        factory.setValidating(true);
        //factory.setAttribute("http://java.sun.com/xml/jaxp/properties/schemaLanguage",
                                      "http://www.w3.org/2001/XMLSchema" );
        //factory.setAttribute("http://java.sun.com/xml/jaxp/properties/schemaSource",schemaFilePath);
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            ExternalResolver er = new ExternalResolver();
            er.addURL(schemaFilePath);
            builder.setEntityResolver(er);
            builder.parse(new File(xmlFilePath));
        } catch (ParserConfigurationException e) {
            validXML = false;
            e.printStackTrace();
        } catch (SAXException e) {
            validXML = false;
            e.printStackTrace();
        } catch (IOException e) {
            validXML = false;
            e.printStackTrace();
        return validXML;
   private class ExternalResolver implements EntityResolver{
        private HashMap urlMap = null;
        public InputSource resolveEntity(String publicId, String systemId){
            System.out.println("resolvedEntity:" +publicId +" and "+systemId);
            if ( urlMap != null && urlMap.get(systemId)!= null ){
                try {
                    return new InputSource(new FileReader(systemId));
                } catch (FileNotFoundException e) {
                    System.out.println("[ERROR] Unable to load entity reference: " + systemId );
            return null;
        public void addURL(String filePath) throws MalformedURLException{
            addURL(new File(filePath).toURL());
        public void addURL(URL url) {
            if ( urlMap == null ){
                urlMap = new HashMap();
            urlMap.put(url, null);
}If I hardcode the DOCTYPE then the file passes through the validation. and printout the System.out that I placed in the entity resolver. However I am getting the following exceptions:
* if I remove the hard-coded DOCTYPE (notice that the EntityResolver output line is not written)
C:\APPS\Eclipse-ws\testbed\bin>java SimpleXMLValidator ..\testdata\ac3.xml  ..\testdata\ngui.dtd
Warning: validation was turned on but an org.xml.sax.ErrorHandler was not
set, which is probably not what is desired.  Parser will use a default
ErrorHandler to print the first 10 errors.  Please call
the 'setErrorHandler' method to fix this.
Error: URI=file:C:/APPS/Eclipse-ws/testbed/bin/../testdata/ac3.xml Line=2: Document is invalid: no grammar found.
Error: URI=file:C:/APPS/Eclipse-ws/testbed/bin/../testdata/ac3.xml Line=2: Document root element "ngui", must match DOCTYPE root "null".* if I uncomment the setAttribute calls:
C:\APPS\Eclipse-ws\testbed\bin>java SimpleXMLValidator ..\testdata\ac3.xml  ..\testdata\ngui.dtd
resolvedEntity:null and file:C:/APPS/Eclipse-ws/testbed/testdata/ngui.dtd
org.xml.sax.SAXParseException: The markup in the document preceding the root element must be well-formed.
        at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
        at org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source)
        at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
        at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
        at org.apache.xerces.impl.XMLScanner.reportFatalError(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentScannerImpl$PrologDispatcher.dispatch(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
        at org.apache.xerces.impl.xs.opti.SchemaParsingConfig.parse(Unknown Source)
        at org.apache.xerces.impl.xs.opti.SchemaParsingConfig.parse(Unknown Source)
        at org.apache.xerces.impl.xs.traversers.XSDHandler.getSchemaDocument(Unknown Source)
        at org.apache.xerces.impl.xs.traversers.XSDHandler.parseSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.loadSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.processJAXPSchemaSource(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.loadSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.findSchemaGrammar(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.handleStartElement(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.startElement(Unknown Source)
        at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
        at org.apache.xerces.impl.XMLNSDocumentScannerImpl$NSContentDispatcher.scanRootElementHook(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
        at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
        at javax.xml.parsers.DocumentBuilder.parse(Unknown Source)
        at SimpleXMLValidator.validate(SimpleXMLValidator.java:61)
        at SimpleXMLValidator.main(SimpleXMLValidator.java:40)* the setAttributes is still active in the compiled class but this time I hardcoded the DOCTYPE again.
C:\APPS\Eclipse-ws\testbed\bin>java SimpleXMLValidator ..\testdata\ac3.xml  ..\testdata\ngui.dtd
resolvedEntity:null and file:C:/APPS/Eclipse-ws/testbed/testdata/ngui.dtd
resolvedEntity:null and file:C:/APPS/Eclipse-ws/testbed/testdata/ngui.dtd
org.xml.sax.SAXParseException: The markup in the document preceding the root element must be well-formed.
        at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
        at org.apache.xerces.util.ErrorHandlerWrapper.fatalError(Unknown Source)
        at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
        at org.apache.xerces.impl.XMLErrorReporter.reportError(Unknown Source)
        at org.apache.xerces.impl.XMLScanner.reportFatalError(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentScannerImpl$PrologDispatcher.dispatch(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
        at org.apache.xerces.impl.xs.opti.SchemaParsingConfig.parse(Unknown Source)
        at org.apache.xerces.impl.xs.opti.SchemaParsingConfig.parse(Unknown Source)
        at org.apache.xerces.impl.xs.traversers.XSDHandler.getSchemaDocument(Unknown Source)
        at org.apache.xerces.impl.xs.traversers.XSDHandler.parseSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.loadSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.processJAXPSchemaSource(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaLoader.loadSchema(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.findSchemaGrammar(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.handleStartElement(Unknown Source)
        at org.apache.xerces.impl.xs.XMLSchemaValidator.startElement(Unknown Source)
        at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(Unknown Source)
        at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
        at org.apache.xerces.impl.XMLNSDocumentScannerImpl$NSContentDispatcher.scanRootElementHook(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
        at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
        at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
        at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
        at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(Unknown Source)
        at javax.xml.parsers.DocumentBuilder.parse(Unknown Source)
        at SimpleXMLValidator.validate(SimpleXMLValidator.java:61)
        at SimpleXMLValidator.main(SimpleXMLValidator.java:40)does anybody know what I am missing here? Thanks.
ciao!
[edit] This posting of mine looks horrible both on IE and Firefox because its HTML tags are all in the text. I posted this question in http://ramfree17.org/capsule/?p=38 which is hopefully more readable.