OSGI question: "dynamic" dependencies and Declarative Services

[Rupert Westenthaler]

Hi

The situation (in pseudo code)

@Component(configurationFactory = true)
MyServiceImpl {

ServiceTracker requiredServiceTracker;

  void activate(ComponentContext context) {
        //create Filter based on properties of the context
        Filter filter;
       requiredServiceTracker = new ServiceTracker(filter);
  }

}

What I want to do is to switch Component instances to "unsatisfied" as soon as 
the required service becomes unavailable and back to the "activate" state as 
soon as it becomes available again.

If I would use @Reference than the Declarative Services would take care of 
activating the service as soon as all dependencies are available. However I con 
not use @Reference here, because the parameter for the Filter are only 
available at runtime an filters in @Reference annotations need to be static.

So basically I am searching for a way (interface, extension point) that allows 
me to use the same System with "runtime" dependencies.

any Ideas?

best
Rupert