List<ProcessingComponent> setDelegates = new LinkedList<ProcessingComponent>();
for (PlanNode child : node) {
setDelegates.add(createComponent(originalQuery, context, child, columns, analyzer));
}
// Then create the select component ...
Operation operation = node.getProperty(Property.SET_OPERATION, Operation.class);
boolean all = node.getProperty(Property.SET_USE_ALL, Boolean.class);
boolean alreadySorted = false; // ????
switch (operation) {
case EXCEPT:
component = new ExceptComponent(context, columns, setDelegates, alreadySorted, all);