Hi everybody , I am full of new for this forum if I made a mistake about opening new topic please warn me also teach me the correct way to get help and maybe one day to help others.
I am trying to learn how can I perform that scenario;
I have two different browser tabs (Vaadin UI instance) with different routes. One for responsible for adding entity to DB ( till here everything works fine) . On other page , responsible to monitor list of entities , I have grid , when I refresh the monitoring page
I can see updated list but I want to learn how can I make it without refreshing . Also I tried to solve using sources on Internet and Vaadin website , it is getting more confused day by day. After 3-4 days tried myself I open the topic. Have a nice day everybody !
@Component
public class EventBus {
private final Set<EventListener> listeners = new HashSet<>();
public void subscribe(EventListener listener) {
listeners.add(listener);
}
public void unsubscribe(EventListener listener) {
listeners.remove(listener);
}
public void notifyUpdate(Object update) {
listeners.forEach(listener -> listener.onEvent(update));
}
}
@Route("monitor")
public class MonitorUserUI extends VerticalLayout implements EventListener {
private final UserService userService;
private final EventBus eventBus;
private final Grid<User> grid = new Grid<>(User.class);
private final ListDataProvider<User> dataProvider;
public MonitorUserUI(UserService userService, EventBus eventBus) {
this.userService = userService;
this.eventBus = eventBus;
add(grid);
// Create a ListDataProvider for the grid
dataProvider = new ListDataProvider<>(userService.getAllUsers());
grid.setDataProvider(dataProvider);
eventBus.subscribe(this);
}
@Override
public void onEvent(Object event) {
if (event instanceof User) {
UI.getCurrent().access(() -> {
User newUser = (User) event;
dataProvider.getItems().add(newUser);
grid.getDataProvider().refreshAll();
});
}
}
@PreDestroy
public void onDestroy() {
eventBus.unsubscribe(this);
}
}
@Route("add")
public class AddUserUI extends VerticalLayout {
private final UserRepository userRepository;
private final EventBus eventBus;
public AddUserUI(UserRepository userRepository, EventBus eventBus) {
this.userRepository = userRepository;
this.eventBus = eventBus;
TextField nameField = new TextField("Name");
TextField emailField = new TextField("Email");
Button addButton = new Button("Add", event -> {
String name = nameField.getValue();
String email = emailField.getValue();
if (!name.isEmpty() && !email.isEmpty()) {
User user = new User();
user.setName(name);
user.setEmail(email);
userRepository.save(user);
eventBus.notifyUpdate(user);
Notification.show("User added successfully");
nameField.clear();
emailField.clear();
} else {
Notification.show("Please enter both name and email");
}
});
FormLayout formLayout = new FormLayout();
formLayout.add(nameField, emailField, addButton);
add(formLayout);
}
}
