public GUIController(int nWorlds) {
mainJFrame = new MainJFrame();
worldsContainer = new WorldsContainerJPanel();
worldsContainer.addPropertyChangeListener(this);
commandJPanel = new CommandJPanel();
commandJPanel.addPropertyChangeListener(this);
for (int i = 0; i < nWorlds; i++) {
GUIWorldController controller = new GUIWorldController();
controller.addObserver(this);