SaxonMwe.java

import net.sf.saxon.Configuration;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.LocalVariableReference;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.sxpath.IndependentContext;
import net.sf.saxon.sxpath.XPathEvaluator;
import net.sf.saxon.sxpath.XPathExpression;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.value.BooleanValue;
import net.sf.saxon.value.SequenceType;

/**
 * @author Clément Fournier
 */
public class SaxonMwe {

    public static void main(String[] args) throws XPathException {
        Configuration configuration = Configuration.newConfiguration();

        IndependentContext staticCtx = new IndependentContext(configuration) {
            {
                declareVariable(null, "falseVar");
            }

            @Override
            public Expression bindVariable(StructuredQName qName) throws XPathException {
                LocalVariableReference local = (LocalVariableReference) super.bindVariable(qName);
                if (qName.getLocalPart().equals("falseVar")) {
                    local.setStaticType(
                            SequenceType.SINGLE_BOOLEAN,
                            BooleanValue.FALSE,
                            0);
                }
                return local;
            }
        };

        final XPathEvaluator xpathEvaluator = new XPathEvaluator(configuration);
        xpathEvaluator.setStaticContext(staticCtx);

        XPathExpression xpathExpression = xpathEvaluator.createExpression(
                "//A[$falseVar][child::*[2]]"
        );


    }

}