Cross-Communication between Vaadin and Swing
Sending Events from Vaadin to Swing
You can send events from Vaadin to Swing using the VaadinSwingEvent
class.
Sending Events
For example, to create a button that sends an event to Swing when clicked:
...
import com.vaadin.swingkit.server.EventEmitter;
import com.vaadin.swingkit.server.EventEmitterFactory;
import com.vaadin.swingkit.core.VaadinSwingEvent;
...
new Button("Send event", event -> {
EventEmitter actionEmitter = EventEmitterFactory.newEventEmitter();
actionEmitter.emit(new VaadinSwingEvent("myEvent")); // asynchronously sends an action event to Swing
});
...
You can add details to the event with parameters using VaadinSwingEventBuilder
:
...
import com.vaadin.swingkit.core.VaadinSwingEventBuilder;
...
EventEmitter actionEmitter = EventEmitterFactory.newEventEmitter();
VaadinSwingEventBuilder myEvent = new VaadinSwingEventBuilder("myEvent");
myEvent.addParam("detail1", "someDetail");
myEvent.addParam("eventDate", new Date());
actionEmitter.emit(myEvent.build());
...
The instances contained inside VaadinSwingEvent
must always be Serializable
to allow the Swing application to parse the data.
Listening to Events
Events emitted from the Vaadin application can be handled with JVaadinPanel.addEventListener()
.
For example:
...
import com.vaadin.swingkit.core.VaadinSwingEvent;
...
JVaadinPanel vaadinPanel = SwingVaadinClient.getBuilder().build('example-view');
vaadinPanel.addEventListener("myEvent", (VaadinSwingEvent event) -> {
// Handle recieved event
});
...
Calling Vaadin Methods from Swing
You can call specific Vaadin application methods from your Swing application.
These methods are exposed using an interface that extends SwingVaadinCallable
.
For example:
...
import com.vaadin.swingkit.core.SwingVaadinCallable;
public interface NameProvider extends SwingVaadinCallable {
String getFirstName();
String getLastName();
}
This interface must be accessible from both your Vaadin server and your Swing application. The best way to achieve this is to have the interface built in an artifact, which is then added as a dependency of both.
Define Callable Methods
Once you have an interface with the methods you want to call from Swing, you need to implement that interface on a view that can be rendered inside a Swing application (see Adding Views). For example:
@Route("example-view")
@Bridge
public class MainView extends VerticalLayout implements NameProvider { 1
private TextField firstName = new TextField("First name");
private TextField lastName = new TextField("Last name");
public MainView() {
firstName.setValue("John");
lastName.setValue("Doe");
add(firstName, lastName);
}
@Override
public String getFirstName() {
return firstName.getValue(); 2
}
@Override
public String getLastName() {
return lastName.getValue(); 3
}
}
-
Implement the shared
NameProvider
interface -
Return the value of the
firstName
field -
Return the value of the
lastName
field
Calling the Methods from Swing
To access the methods exposed from the Vaadin application, use JVaadinPanel.as(SwingVaadinCallable)
.
It returns an instance of the shared interface, and you can then call the exposed methods on that instance.
For example:
// Create the view
JVaadinPanel vaadinPanel = SwingVaadinClient.getBuilder().build("example-view");
// Add the panel to your swing application
// ...
// Query Vaadin using your NameProvider interface
NameProvider np = vaadinPanel.as(NameProvider.class);
// This returns "John", or whatever the user has typed to the field
np.getFirstName();