int op = opNode.operation;
int opInfo = operationFormat(op);
if ((opInfo & OP_ORDERBY_MASK) > 0) {
stack.remove(stack.size() - 1);
ConstraintNode node = (ConstraintNode) stack.get(stack.size() - 1);
if (!(node instanceof ConstraintField)) {
throw new JDOFatalInternalException(I18NHelper.getMessage(messages,
"core.constraint.needfieldnode")); // NOI18N
} else {