Pushing Images Vaadin Java

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i am trying to create a turn-base card game in Vaadin-Java, everything was going well so far, but i have a problem with pushing Vaadin Images to other UI. I did copy Broadcast/BroadcasterView Class from Vaadin Documentation and it works as intended, but not for images.

public class Broadcaster {
    static Executor executor = Executors.newSingleThreadExecutor();

    static LinkedList<Consumer<String>> listeners = new LinkedList<>();

    public static synchronized Registration register(
            Consumer<String> listener) {
        listeners.add(listener);

        return () -> {
            synchronized (Broadcaster.class) {
                listeners.remove(listener);
            }
        };
    }

    public static synchronized void broadcast(String message) {
        for (Consumer<String> listener : listeners) {
            executor.execute(() -> listener.accept(message));
        }
    }
}

@Push
@Route("broadcaster")
public class BroadcasterView extends Div {
    VerticalLayout messages = new VerticalLayout();
    Registration broadcasterRegistration;

    // Creating the UI shown separately

    @Override
    protected void onAttach(AttachEvent attachEvent) {
        UI ui = attachEvent.getUI();
        broadcasterRegistration = Broadcaster.register(newMessage -> {
            ui.access(() -> messages.add(new Span(newMessage)));
        });
    }

    @Override
    protected void onDetach(DetachEvent detachEvent) {
        broadcasterRegistration.remove();
        broadcasterRegistration = null;
    }
}

public BroadcasterView() {
    TextField message = new TextField();
    Button send = new Button("Send", e -> {
        Broadcaster.broadcast(message.getValue());
        message.setValue("");
    });

    HorizontalLayout sendBar = new HorizontalLayout(message, send);

    add(sendBar, messages);
}

the code above works fine for Strings, Vaadin Icons etc, but when i replace for and naturally change the broadcast method, there is no reaction.

i've searched for the solution throughout the internet, but it seems, people don't need to push images or it's simply not possible here. I thought that this is perhaps the matter of payload, but it doesn't work even for 5px x 5px images

perhaps one of You have encountered such problem and found solution?

vaadin broadcast push image websocket
1 Answers

You need to pass data through the broadcaster, but what you write about your attempts makes me suspect that you've been trying to pass UI components (i.e. instances of com.vaadin.flow.component.html.Image). That won't work because a UI component instance cannot be attached to multiple locations (i.e. multiple browser windows in this case) at the same time.

What you can try is to pass the data (e.g. a String with the image URL) through the broadcaster and then let each subscriber create their own Image component based on the data that they receive.

user_23769540
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