if (selectedDisplay.getParentDisplay() == null) browser.accept(visitor); else selectedDisplay.accept(visitor);
if (selectedDisplay.getParentDisplay() == null) return; selectedDisplay.accept(visitor); if (selectedDisplay instanceof ImageSet) { Layout layout = LayoutFactory.createLayout( LayoutFactory.SQUARY_LAYOUT); layout.visit((ImageSet) selectedDisplay); }
    public void execute()    {        ZoomVisitor visitor = new ZoomVisitor(model);        Browser browser = model.getBrowser();        ImageDisplay selectedDisplay = browser.getSelectedDisplay();        if (selectedDisplay.getParentDisplay() == null) //root            browser.accept(visitor);        else selectedDisplay.accept(visitor);    }