跟踪OSGi中的特定捆绑包

Question

I'm new using OSGi, I have a doubt about tracking Bundles. I'm using BundleTracker because I want specific bundles, and I want to know which bundle I am using by their IDs. Some Bundles (3) implement the same interface. I want to track just those bundles that implement that interface. How can I do this?

Answer 1

If you want to select a specific service you can use service properties for that. This is completely agnostic of bundles. What that means is that you register your service-implementations with specific properties (this is what the Dictionary -argument in BundleContext.registerService is for).

Then you can use BundleContext.getServiceReferences and specify a filter-expression (the syntax is described here ) that only selects the service with the correct property. You could set this up so that you always get an array or collection with at most one element.

This all becomes much easier if you use declarative services , because then you can just specify the property and the filter in the service-descriptor of the providing and consuming component respectively. You can also make one or both ends of it configurable via the configuration admin (properties in the configuration of a service-component are propagated as properties of the exposed services or consumed references). I would really suggest you check out declarative services before starting any serious work in OSGi.

Note that you should be careful to not implement a hard-coded wiring this way, because that would kill modularity.