Abstract components via org.osgi.service.component annotations

Question

I am migrating from org.apache.felix.scr annotations to org.osgi.service.component annotations. I have a set of Components that inherit from a common abstract class. In the felix case, I can use a @Component annotation with the option componentAbstract=true on the super class, and then use @Reference annotation in the super class. I cannot find how to migrate this to osgi annotations.

Is it possible to use Component annotations in a super class of a Component? And if so, what is then the appropriate way to handle the properties and metatype generation?

So, what I am looking for, is something like this

/* No component definition should be generated for the parent, as it is
   abstract and cannot be instantiated */
@Component(property="parent.property=parentValue")
public abstract class Parent {
  @Reference
  protected Service aService;

  protected activate(Map<String,Object> props) {
    System.out.println("I have my parent property: "+props.get("parent.property"));

  @Override
  public abstract void doSomething();
}

/* For this class, the proper Component definition should be generated, also
   including the information coming from the annotations in the parent */
@Component(property="child.property=childValue")
public class Child extends Parent {

  @Activate
  public activate(Map<String,Object> props) {
    super.activate(props);
    System.out.println("I have my child property: "+props.get("child.property"));
  }

  public void doSomething() {
    aService.doSomething();
  }
}

Answer 1

By default BND will not process DS annotations in parent classes. You can change that with -dsannotations-options: inherit but please see http://enroute.osgi.org/faq/ds-inheritance.html why you shouldn't!

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2021-02-23 UPDATE: It seems like the page mentioned above is no longer available. I don't know if it was moved elsewhere or simply removed but its content (in Markdown format) is still available on GitHub: https://github.com/osgi/osgi.enroute.site/blob/pre-R7/_faq/ds-inheritance.md