Hi,

Yes, it' possible to have several services by component (imho, it
should be avoided when possible to avoid unexpected cascading
refresh).

A component can implement multiple interfaces, and the @Component
annotation accepts the list of exposed interfaces.

Regards
JB

On Sat, Mar 16, 2024 at 7:44 AM Steinar Bang <s...@dod.no> wrote:
>
> Can a Java class implementing a DS component expose more than one
> OSGi service?
>
> My usecase is that I have a DS component implementing a servlet Filter,
> plugging into the web whiteboard.
>  
> https://github.com/steinarb/oldalbum/blob/master/oldalbum.web.security/src/main/java/no/priv/bang/oldalbum/web/security/OldAlbumShiroFilter.java#L35
>
> And then I would like a way to retrigger configuration of the filter and
> the simplest way would be if the filter could expose a service with a
> method that could be used to trigger reconfiguration.
>
> What if I subtype the Filter interface with a new interface and expose
> that interface from the component, would still be able to "find" the web
> whiteboard? (I think not, because if I remember correctly if a class
> does not directly implement an interface, the interface for the service
> must be specified in @Component annotation...?)
>
> Hm... looks like the service parameter of @Component can be an array...?
>  
> https://docs.osgi.org/specification/osgi.cmpn/8.0.0/service.component.html#org.osgi.service.component.annotations.Component.service--
>
> I'll try.
>
> Hm... looks like the Filter interface has an init() method...?
>  
> https://docs.oracle.com/cd/E17802_01/products/products/servlet/2.5/docs/servlet-2_5-mr2/javax/servlet/Filter.html#init(javax.servlet.FilterConfig)
>
> Could that be used, I wonder?
>
> No, implemented by shiro AbstractFilter, probably best not to mess with
> that...?
>
> So: I will try a new interface with a single callback method and inject
> that service into a REST endpoint and see if I can make the filter
> reconfigure itself.
>

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