How to get XML element information in case of SAXParseException

Question

When validating an xml source against an xsd schema in a standard java environment, i cannot find a way to get the information about the element that failed validation (in many specific cases).

When catching a SAXParseException, the information of the element is gone. However, when debugging into the xerces.XmlSchemaValidator, i can see that the reason is the specific error message that is not defined to give away information about the element.

For example (and this is also the case in my java demo) the "cvc-mininclusive-valid" error is defined this way: cvc-minInclusive-valid: Value ''{0}'' is not facet-valid with respect to minInclusive ''{1}'' for type ''{2}''. https://wiki.xmldation.com/Support/Validator/cvc-mininclusive-valid

What I would would prefer is, that this kind of message would be produced: cvc-type.3.1.3: The value ''{1}'' of element ''{0}'' is not valid. https://wiki.xmldation.com/Support/Validator/cvc-type-3-1-3

When debugging into xerces.XMLSchemaValidator, I can see that there are two consecutive calls to reportSchemaError(...) - the second only occuring, if the first one did return without an exception being thrown.

Is there any way to configure the validator to use the second way of reporting OR to enrich the SAXParseException with the element information?

Please see my copy&paste&runnable example code below for further explanation:

String xsd =
            "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n" +
                    "<xs:schema xmlns:xs=\"http://www.w3.org/2001/XMLSchema\" version=\"1.0\">" +
                    "<xs:element name=\"demo\">" +
                    "<xs:complexType>" +
                    "<xs:sequence>" +

                    // given are two elements that cannot be < 1
                    "<xs:element name=\"foo\" type=\"xs:positiveInteger\" minOccurs=\"0\" maxOccurs=\"unbounded\" />" +
                    "<xs:element name=\"bar\" type=\"xs:positiveInteger\" minOccurs=\"0\" maxOccurs=\"unbounded\" />" +

                    "</xs:sequence>" +
                    "</xs:complexType>" +
                    "</xs:element>" +
                    "</xs:schema>";

    String xml =
            "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
                    "<demo>" +

                    "<foo>1</foo>" +
                    // invalid!
                    "<foo>0</foo>" +
                    "<bar>2</bar>" +

                    "</demo>";

    Validator validator = SchemaFactory
            .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI)
            .newSchema(new StreamSource(new StringReader(xsd)))
            .newValidator();


    try {
        validator.validate(new StreamSource(new StringReader(xml)));
    } catch (SAXParseException e) {

        // unfortunately no element or line/column info:
        System.err.println(e.getMessage());

        // better, but still no element info:
        System.err.println(String.format("Line %s -  Column %s - %s",
                e.getLineNumber(),
                e.getColumnNumber(),
                e.getMessage()));
    }

Answer 1

Try using an error handler:

    public class LoggingErrorHandler implements ErrorHandler {

    private boolean isValid = true;

    public boolean isValid() {
        return this.isValid;
    }

    @Override
    public void warning(SAXParseException exc) {
        System.err.println(exc);
    }

    @Override
    public void error(SAXParseException exc) {
        System.err.println(exc);
        this.isValid = false;
    }

    @Override
    public void fatalError(SAXParseException exc) throws SAXParseException {
        System.err.println(exc);
        this.isValid = false;
        throw exc;
    }
}

and use it in validator:

        Validator validator = SchemaFactory
                .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI)
                .newSchema(new StreamSource(new StringReader(xsd)))
                .newValidator();
        LoggingErrorHandler errorHandler = new LoggingErrorHandler();
        validator.setErrorHandler(errorHandler);
        validator.validate(new StreamSource(new StringReader(xml)));
        return errorHandler.isValid();