Data-Centric Applications with Vaadin 8

Implementing the create and update operations

The create CRUD operation starts when the user clicks the add button. Similarly, the update CRUD operation starts when the user clicks the update button. We need the following infrastructure code:

...private void initBehavior() {    ...    add.addClickListener(e -> showAddWindow());    edit.addClickListener(e -> showEditWindow());}private void showAddWindow() {    UserFormWindow window = new UserFormWindow("Add", new User());    getUI().addWindow(window);}private void showEditWindow() {    UserFormWindow window = new UserFormWindow("Edit", grid.asSingleSelect().getValue());    getUI().addWindow(window);}

When any of the buttons is clicked, we show a UserFormindow (implemented shortly). For the add button, we pass ...