How to reference a service in a non-service class?

Question

As the title suggests, I would like to reference a service in a non-service class, the way I can think of is as follows :

@Component( immediate = true )
public class Foo {
    
    @Reference
    private Bar bar ;
    
}

But Foo seems to be instantiated and references bar when the plugin it's in starts up, if I new Foo(), bar is null.

Is there any way to make Foo not instantiate automatically, but rather I can new it myself and make bar not null ?

In other words, must the Component be created when the plugin starts ?

Have you read something like the Vogella tutorial - https://www.vogella.com/tutorials/OSGi/article.html ? My understanding is that `immediate=true` starts the service as soon as possible which is not what you want here. You can't use `new` as that doesn't do any sort of injection. The Vogella tutorial talks about getting services from the bundle context or using ServiceTracker. — greg-449, Jul 11 '23 at 12:13
Yes, I know I can use the bundle context or ServiceTracker or annotate the `bar` with `@Inject` and then get the service via `ContextInjectionFactory.inject( new Foo(), context )`. I'm new to DS and I'm looking into it, and I was wondering if I could use `@Reference` to get the service in a similar way to `ContextInjectionFactory.inject()`, but it doesn't seem to work! — Bourbon_7, Jul 11 '23 at 13:00

score 0 · Answer 1 · answered Jul 11 '23 at 13:30

0

Use the newest DS spec from OSGi R7 or R8. It allows constructor injection of services. This way you can inject the service also when doing new.

answered Jul 11 '23 at 13:30

1 Answers1