XQuery executes Java function with Saxon 9-HE

Question

I tried to follow the answer from here Saxon-HE Integrated Extension Functions | how and where? to execute some java methods and return a String, which is kind of the same thing as the example.

Difference is I am running XQuery instead of XSLT.

Problem is I get an error saying no namespace defined when running the XQuery.

Question is can I use the XSLT trick for XQuery ?

Code for now : In specific method :

TransformerFactory factory = TransformerFactory.newInstance();
TransformerFactoryImpl tFactoryImpl = (TransformerFactoryImpl) factory;
config = tFactoryImpl.getConfiguration();

The method used to set the processor :

public void addFunctionLibrary(JavaSaxonLib tsj) {
    Processor processor = (Processor) config.getProcessor();
    ExtensionFunction javaCall = tsj;
    processor.registerExtensionFunction(javaCall);
}

The class to test the ExtensionFunction :

public class JavaSaxonLib implements ExtensionFunction {

    String namespace = "";
    String nsURL = "";

    public JavaSaxonLib(String namespace, String nsURL) {
        this.namespace = namespace;
        this.nsURL = nsURL;
    }

    @Override
    public QName getName() {
        return new QName(nsURL, namespace);
    }

    @Override
    public SequenceType getResultType() {
        return SequenceType.makeSequenceType(ItemType.STRING, OccurrenceIndicator.ONE);
    }

    @Override
    public SequenceType[] getArgumentTypes() {
        return new SequenceType[] {};
    }

    @Override
    public XdmValue call(XdmValue[] arguments) throws SaxonApiException {
        String result = "Saxon is being extended correctly.";
        return new XdmAtomicValue(result);
    }
}

In the main method :

JavaSaxonLib jsl = new JavaSaxonLib(namespace, nsURL);
saxMan.addFunctionLibrary(jsl);

Thanks ! :-)

score 0 · Accepted Answer · answered Sep 04 '18 at 15:07

Finally ! I managed to make it to work.

Tricky part is to modify the xquery to fool Saxon 9-HE to execute java method with ExtensionFunction and a Classloader.

Too bad we cannot send private message as if someone is interested in the complete answer I cannot share it properly.

XQuery executes Java function with Saxon 9-HE

1 Answers1