How to get a Prototype Scoped Osgi Component (which turn out to also be Vaadin component) reference programmatically

Question

I am using Vaadin 21 in Apache Karaf, an Osgi container. What i want to do :

• Create a vaadin Component, annotates it with @Component(scope=ScopeService.PROTOTYPE)

• In the View with the @Route, the Vaadin doc says that we cannot use injection dependency to get the Osgi Component reference

• To get the reference, the doc says to use :

  ServiceReference<MyComponent> reference = ctx.getServiceReference(MyService.class);
  MyComponent myComponent = ctx.getService(reference);```
  
  

• I have a problem when i refresh my screen, the instance of MyComponent stays the same

• To avoid that, i found an alternative :

      ServiceReference<MyComponent> reference = ctx.getServiceReference(MyComponent.class);
      ServiceObjects<MyComponent> res = ctx.getServiceObjects(reference);
      MyComponent myComponent = res.getService();```
  
  
  
  

Has anyone got a better way to get my Prototype vaadin and osgi component Reference ? Here is my code (from base-starter-flow-osgi) :

public class MainView extends VerticalLayout {

    public MainView() {
        
        BundleContext ctx = FrameworkUtil.getBundle(MyComponent.class).getBundleContext();
        ServiceReference<MyComponent> reference = ctx.getServiceReference(MyComponent.class);
        ServiceObjects<MyComponent> res = ctx.getServiceObjects(reference);
        prestas = res.getService();

        add(myComponent);
    }
}
@Component(service=MyComponent.class, scope=ServiceScope.PROTOTYPE)
public class MyComponent extends Div{
    private static final long serialVersionUID = -8573895829405499446L;

    @Override
    protected void onAttach(AttachEvent attachEvent) {
        super.onAttach(attachEvent);
        add(new Span("Hello World!"));
    }
    
}

Answer 1

Simplified processes to your solution.

public class OSGIServiceUtil {

  private static final Map<Class<?>, ContextReference<?>> references = new ConcurrentHashMap<>();

  public static <T> T get(Class<T> clazz) {
    ContextReference<?> reference = references.computeIfAbsent(clazz, k -> {
      BundleContext bundleContext = FrameworkUtil.getBundle(clazz).getBundleContext();
      return new ContextReference<>(bundleContext, bundleContext.getServiceReference(clazz));
    });
    // The casting part you can have special handling based on your company code style
    return (T) reference.getService();
  }
}

@AllArgsConstructor
class ContextReference<T> {

  private BundleContext bundleContext;
  private ServiceReference<T> reference;

  T getService() {
    return bundleContext.getServiceObjects(reference).getService();
  }
}

In client

MyComponent myComponent = OSGIServiceUtil.get(MyComponent.class);