Migration

When the Tabbed Application Mode add-on is added, Vaadin’s navigation functionality is disabled, so no navigation events are sent to views, such as BeforeEnterEvent or AfterNavigationEvent. Because of that, you may need to refactor some of your views that rely on these events.

To simplify the process of refactoring, the base View class provides the processBeforeEnterInternal() method that accepts a BeforeEnterEvent as an argument.

Regular Views

Consider an example where a view has a mandatory route parameter that is used to find required data for further operation:

@Route(value = "role-assignment/:username", layout = DefaultMainViewParent.class)   (1)
@ViewController(id = "RoleAssignmentView")
@ViewDescriptor(path = "role-assignment-view.xml")
public class RoleAssignmentView extends StandardView {

    private UserDetails user;

    @Override
    public void beforeEnter(BeforeEnterEvent event) {
        findUser(event.getRouteParameters());   (2)
        super.beforeEnter(event);
    }

    private void findUser(RouteParameters routeParameters) {
        String username = routeParameters.get("username")
                .orElseThrow(() -> new IllegalStateException("Username not found"));    (3)

        String decodedUsername = urlParamSerializer.deserialize(String.class, username);

        user = userRepository.loadUserByUsername(decodedUsername);
    }
}

1	View route includes mandatory parameter
2	Obtains route parameters and use them to find a user instance.
3	Gets particular route parameter and loads a user instance.

To make this view work in a tab, override the processBeforeEnterInternal() method and call the findUser method inside it:

@Override
protected void processBeforeEnterInternal(BeforeEnterEvent event) {
    super.processBeforeEnterInternal(event);

    findUser(event.getRouteParameters());
}

Detail Views

A detail view has two methods to initialize the edited entity:

setupEntityToEdit(String) - invoked when a detail view is opened by navigation and the edited entity is loaded by its id, which is passed as a route parameter.
setupEntityToEdit(Entity) - invoked when a detail view is opened in a dialog window and the edited entity is passed directly.

Consider an example where your detail view has custom code that initializes edited entity based on route parameter:

@Override
protected void initExistingEntity(String serializedEntityCode) {
    String code = urlParamSerializer.deserialize(String.class, serializedEntityCode);
    ResourceRole roleByCode = roleRepository.findRoleByCode(code);

    ResourceRoleModel resourceRoleModel = roleModelConverter.createResourceRoleModel(roleByCode);

    childRolesDc.mute();
    childRolesDc.setItems(loadChildRoleModels(resourceRoleModel));
    childRolesDc.unmute();

    ResourceRoleModel merged = dataContext.merge(resourceRoleModel);
    roleModelDc.setItem(merged);
}

In the example above, the actual edited entity instance is obtained by converting the data stored in the database, which is loaded using the id passed as a route parameter. Since this view isn’t intended to be opened in a dialog window, it lacks similar code for the directly passes entity instance. To make this view work in a tab, override the setupEntityToEdit() method and provide an empty implementation:

@Override
protected void setupEntityToEdit(ResourceRoleModel entityToEdit) {
    // do nothing
}