Vaadin 23 override internal error message

Question

when an error occurs inside the application, the user sees the following message:

Is it possible to override it?

I aaded the following:

public class CustomErrorHandler implements ErrorHandler {

    private static final Logger logger = LoggerFactory.getLogger(CustomErrorHandler.class);

    @Override
    public void error(ErrorEvent errorEvent) {
        logger.error("Something wrong happened", errorEvent.getThrowable());
        Notification.show("An internal error has occurred. Please contact support.");
        if (UI.getCurrent() != null) {
            UI.getCurrent().access(() -> {
                Notification.show("An internal error has occurred. Please contact support.");
            });
        }
    }

}

@Component
public class ServiceListener implements VaadinServiceInitListener {

    private static final Logger logger = LoggerFactory.getLogger(LanguageReceiver.class);

    @Override
    public void serviceInit(ServiceInitEvent event) {

        event.getSource().addSessionInitListener(
                initEvent -> {
                    logger.info("A new Session has been initialized!");
                    VaadinSession.getCurrent().setErrorHandler(new CustomErrorHandler());
                });

        event.getSource().addUIInitListener(
                initEvent -> logger.info("A new UI has been initialized!"));
    }

}

@ParentLayout(MainLayout.class)
@AnonymousAllowed
public class ExceptionHandler extends VerticalLayout implements HasErrorParameter<Exception> {

    static final Logger logger = LoggerFactory.getLogger(ExceptionHandler.class);

    @Override
    public int setErrorParameter(BeforeEnterEvent event, ErrorParameter<Exception> parameter) {

        logger.error("Error", parameter.getException());

        Label label = new Label(parameter.getException().getMessage());
        add(label);

        return HttpServletResponse.SC_NOT_FOUND;
    }

}

but still unable to override the mentioned error on the screenshot above. Please show how to do this.

STaefi · Accepted Answer · 2022-09-09T11:56:55.870

Generally, you need to extend SystemMessages and override getInternalErrorMessage().

Then you can register it using:

YourSystemMessages sysMessages = new YourSystemMessages();
VaadinService.getCurrent().setSystemMessagesProvider(systemMessagesInfo -> sysMessages);

and if you want to reset it to the default one:

VaadinService.getCurrent().setSystemMessagesProvider(DefaultSystemMessagesProvider.get());

In a Spring Boot based application you can register it in any implementation of VaadinServiceInitListener such as:

@Component
public class CustomSystemMessagesInitializer implements VaadinServiceInitListener {

    @Autowired
    private YourSystemMessages sysMessages;
    // You can provide your SystemMessages instance in any way that suits you.

    @Override
    public void serviceInit(ServiceInitEvent serviceInitEvent) {
        serviceInitEvent.getSource()
                .setSystemMessagesProvider(systemMessagesInfo -> sysMessages);
    }

}

Note that serviceInitEvent.getSource() returns the VaadinService instance, so it can be used as the reference as an alternative to VaadinService.getCurrent.

Thank you! In which place in Vaadin SpringBoot application it is better to invoke `VaadinService.getCurrent().setSystemMessagesProvider` ? — alexanoid, Sep 09 '22 at 11:34
This can be in any implementation of `VaadinServiceInitListener` in your application, as its `serviceInit` method is called just after the initialization of Vaadin Service, and you can use the `serviceInitEvent.getSource()` to obtain the service instance as an alternative to `VaadinService.getCurrent()`. — STaefi, Sep 09 '22 at 11:45

Vaadin 23 override internal error message

1 Answers1