String select = getRuleSelectString(attrSet.getAttributeSetID(), attr.getAttributeID());
NodeList rules = XPathUtil.selectNodes(select, xml);
int rCnt = rules.getLength();
for (int r = 0; r < rCnt; r++) {
Error err = validateAttr(attr, rules.item(r));
if (err != null) {
if (errSet == null)
errSet = new ErrorSet(attrSet.getAttributeSetID());
errSet.addError(err);