JSONSubScan(List<JSONGroupScan.ScanEntry> readEntries, JSONStorageEngine engine, FieldReference ref){
this.readEntries = readEntries;
this.storageEngine = engine;
OperatorCost cost = new OperatorCost(0, 0, 0, 0);
Size size = new Size(0, 0);
for (JSONGroupScan.ScanEntry r : readEntries) {
cost = cost.add(r.getCost());
size = size.add(r.getSize());
}
this.cost = cost;
this.size = size;
this.ref = ref;
}