Here's as simple a test case as I can muster.
import java.io.IOException;
import java.io.StringReader;
import nu.xom.Builder;
import nu.xom.Document;
import nu.xom.Nodes;
import nu.xom.ParsingException;
import nu.xom.ValidityException;
import nu.xom.XPathContext;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class ERHTest {
// This test succeeds
@Test
public void testNot() throws ValidityException, ParsingException, IOException {
Document doc = new Builder().build(new StringReader("<hi/>"));
Nodes query = doc.query("//*[not(self::human)]", XPathContext.makeNamespaceContext(doc.getRootElement()));
assertEquals(1, query.size());
}
// This test fails with
// nu.xom.XPathException: XPath error: No Such Function {there://mr.space/alien}:not
@Test
public void testNotWithNamespace() throws ValidityException, ParsingException, IOException {
Document doc = new Builder().build(new StringReader("<hi xmlns='there://mr.space/alien'/>"));
XPathContext context = XPathContext.makeNamespaceContext(doc.getRootElement());
context.addNamespace("a", doc.getRootElement().getNamespaceURI());
Nodes query = doc.query("//*[not(self::a:human)]", context);
assertEquals(1, query.size());
}
// This test succeeds
@Test
public void testNotWithNamespaceWorkaround() throws ValidityException, ParsingException, IOException {
Document doc = new Builder().build(new StringReader("<hi xmlns='there://mr.space/alien'/>"));
XPathContext context = XPathContext.makeNamespaceContext(doc.getRootElement());
context.addNamespace("a", doc.getRootElement().getNamespaceURI());
context.addNamespace("f", "");
Nodes query = doc.query("//*[f:not(self::a:human)]", context);
assertEquals(1, query.size());
}
}
nu.xom.XPathException: XPath error: No Such Function {there://mr.space/alien}:not
at nu.xom.Node.query(Unknown Source)
at ERHTest.testNotWithNamespace(ERHTest.java:30)
<snip>
Caused by: nu.xom.jaxen.UnresolvableException: No Such Function {there://mr.space/alien}:not
at nu.xom.jaxen.SimpleFunctionContext.getFunction(Unknown Source)
at nu.xom.jaxen.ContextSupport.getFunction(Unknown Source)
at nu.xom.jaxen.Context.getFunction(Unknown Source)
at nu.xom.jaxen.expr.DefaultFunctionCallExpr.evaluate(Unknown Source)
at nu.xom.jaxen.expr.DefaultPredicate.evaluate(Unknown Source)
at nu.xom.jaxen.expr.PredicateSet.applyPredicate(Unknown Source)
at nu.xom.jaxen.expr.PredicateSet.evaluatePredicates(Unknown Source)
at nu.xom.jaxen.expr.DefaultNameStep.evaluate(Unknown Source)
at nu.xom.jaxen.expr.DefaultLocationPath.evaluate(Unknown Source)
at nu.xom.jaxen.expr.DefaultAbsoluteLocationPath.evaluate(Unknown Source)
at nu.xom.jaxen.expr.DefaultXPathExpr.asList(Unknown Source)
at nu.xom.jaxen.BaseXPath.selectNodesForContext(Unknown Source)
at nu.xom.jaxen.BaseXPath.selectNodes(Unknown Source)
at nu.xom.JaxenConnector.selectNodes(Unknown Source)
... 24 more
While debugging I can see that the SimpleFunctionContext object has a function list that includes not, but it has an empty namespace. It appears the namespace of the root node of the XML document doesn't match the namespace of the 'not' function, resulting in the 'not' function not being found.
Why should I have to declare a namespace for functions? Does the XPath spec require this?
Would specifying a namespace for the not() function work across other XPath implementations?
Avery J. Regier
RegierAveryJ at JohnDeere.com