private Slot<ColumnView> addColumn(Collection<NodeMatch> nodes) { // Recursively expand any calculated fields List<Slot<ColumnView>> expandedNodes = Lists.newArrayList(); for (NodeMatch node : nodes) { switch (node.getType()) { case FORM_NAME: case RECORD_ID: case FORM_ID: expandedNodes.add(batch.addColumn(filterLevel, node)); break; case FIELD: if (node.isCalculated()) { expandedNodes.add(expandCalculatedField(node)); } else { expandedNodes.add(batch.addColumn(filterLevel, node)); } break; } } if(expandedNodes.isEmpty()) { return batch.addEmptyColumn(filterLevel, rootFormClass); } else if(expandedNodes.size() == 1) { return expandedNodes.get(0); } else { return new FunctionCallSlot(CoalesceFunction.INSTANCE, expandedNodes); } }