Hi
Am 03.02.2014 um 09:41 schrieb Chetan Mehrotra <[email protected]>:
> Hi,
>
> For SLING-3264 I was thinking to provide Inventory integration in
> Commons Logs. However the Commons Log bundle starts at level 1 while
> the Inventory bundle starts at Level 5. The log bundle would use the
> ServiceFactory approach to expose the Inventory service and would not
> have required dependency on Inventory API.
>
> So just wanted to confirm that would it be fine to depend on classes
> from a bundle which starts at later start level or not?
Sure. This is what we are using ServiceFactory and dynamic/delayed import all
over places. See for example the Configuration Admin binding the Apache Felix
SCR bundle.
So, what seems to boild down to kind of a best practice is to:
* use ServiceFactory for optional services
* use Import-Package with resolution:=optional to have
static wiring if possible
* use DynamicImport-Package to have dynamic wiring
on-demand
It is just very important to thouroughly test this to not get inadvertend
ClassNotFoundExceptions, for example if the optional classes appear in the
method signature of a required class (see the
ResourceResolverActivator.getFeaures() method which returns Object to work
around this issue).
Regards
Felix
