@Override
 public void resetSize(int newSize) {
   this.grid = gridFactory.create(newSize);
   reset();
   Event event = new SizeChangedEvent();
   notifyObservers(event);
 }
 @Inject
 public SudokuController(IGridFactory gridFactory) {
   this.gridFactory = gridFactory;
   this.grid = gridFactory.create(NORMALGRID);
   this.undoManager = new UndoManager();
 }