@Override
protected IScalarEvaluator createEvaluator(IHyracksTaskContext ctx, IScalarEvaluator[] args)
throws AlgebricksException {
final XSQNamePointable qnamep = (XSQNamePointable) XSQNamePointable.FACTORY.createPointable();
final SequencePointable seqp = (SequencePointable) SequencePointable.FACTORY.createPointable();
final UTF8StringPointable stringp = (UTF8StringPointable) UTF8StringPointable.FACTORY.createPointable();
final ArrayBackedValueStorage abvs = new ArrayBackedValueStorage();
final DataOutput dOut = abvs.getDataOutput();
return new AbstractTaggedValueArgumentScalarEvaluator(args) {
@Override
protected void evaluate(TaggedValuePointable[] args, IPointable result) throws SystemException {
TaggedValuePointable tvp1 = args[0];
// Only accept a QNames or empty sequence.
if (tvp1.getTag() == ValueTag.SEQUENCE_TAG) {
tvp1.getValue(seqp);
if (seqp.getEntryCount() == 0) {
XDMConstants.setEmptySequence(result);
return;
}
// Pass through.
}
if (tvp1.getTag() != ValueTag.XS_QNAME_TAG) {
throw new SystemException(ErrorCode.FORG0006);
}
tvp1.getValue(qnamep);
qnamep.getPrefix(stringp);
try {
// Return empty sequence if no prefix.
if (qnamep.getPrefixLength() == 0) {
XDMConstants.setEmptySequence(result);
} else {
abvs.reset();
dOut.write(ValueTag.XS_NCNAME_TAG);
dOut.write(stringp.getByteArray(), stringp.getStartOffset(), stringp.getLength());
result.set(abvs);
}
} catch (Exception e) {
throw new SystemException(ErrorCode.SYSE0001, e);
}