LOG.debug("right " + right.pprint() + " returned: " + rval.getLength());
	public Sequence eval(StaticContext context, DocumentSet docs, Sequence contextSequence, 		Item contextItem) throws XPathException {				Sequence lval = left.eval(context, docs, contextSequence, contextItem);		LOG.debug("left " + left.pprint() + " returned: " + lval.getLength());		Sequence rval = right.eval(context, docs, contextSequence, contextItem);		LOG.debug("right " + right.pprint() + " returned: " + rval.getLength());		if(lval.getItemType() != Type.NODE || rval.getItemType() != Type.NODE)			throw new XPathException("union operand is not a node sequence");		long start = System.currentTimeMillis();        NodeSet result = ((NodeSet)lval).union((NodeSet)rval);		LOG.debug("union found " + result.getLength() + " in "+ (System.currentTimeMillis() - start));		return result;	}