Thanks again Robert, > I'm not sure about the reason behind it, but I think that the > Felix-specific SCR annotations predate the OSGi spec for annotations.
That occurred to me, but the naming was so similar that I ignored it. SCR has been very inspirational then! In that case, would it be an idea to extend the annotation’s target to methods as well as fields? > Hm, have you tried setting the property annotation on the class, > rather than a field? In my case, the value must be computed and retrieved from an external source (the first time) but can then be cached and expected not to change, which is why I have a service to provide it. I wonder how I could achieve that with configuration? Many thanks, Dan. On 2 Nov 2013, at 13:57, Robert Munteanu <[email protected]> wrote: > On Sat, Nov 2, 2013 at 3:50 PM, Daniel McGreal <[email protected]> wrote: >> Hi Robert, >> >> Thanks for your reply. I was not actually aware the plugin generated the >> methods, that’s very helpful! >> >> I have implemented the bind method in such a manner, but am forced to have a >> pointless (and potentially destructively misleading) field that I can’t >> prevent other people from using and therefore have to document that it’s not >> to be used or put effort into writing the class to ensure it’s null and >> thread safe on the reference - a task that would be implicit if the field >> never existed. To illustrate, when all is well in my class I have to have a >> warning that the field is unused, whereas what I need is a warning if it is! > > Hm, have you tried setting the property annotation on the class, > rather than a field? You might need to use a holder @Properties > annotation if you have more than one annotation. > >> >> I am curious as to the rationale of it being a field annotation rather than >> a method (or method + field), as it must have been a conscious choice to >> deviate from the way the OSGi spec does it. > > I'm not sure about the reason behind it, but I think that the > Felix-specific SCR annotations predate the OSGi spec for annotations. > > Robert > >> >> Best, Dan. >> >> >> On 2 Nov 2013, at 13:43, Robert Munteanu <[email protected]> wrote: >> >>> Hi Dan, >>> >>> On Sat, Nov 2, 2013 at 3:12 PM, Daniel McGreal <[email protected]> wrote: >>>> Hi Felix users, >>>> I wonder if anyone knows why the Felix @Reference annotations are valid on >>>> fields, but not methods, whereas the opposite is true for the OSGi >>>> standard @Reference annotation. >>>> I would very much like to have a service bound, which I don’t keep a >>>> reference to in the rest of my class (so that I can guarantee that code in >>>> the rest of the class doesn’t depend directly on the reference). For >>>> example: >>>> >>>> int value; >>>> private void bindValueGetter(ValueGetter s){ >>>> value = s.getValue(); >>>> } >>>> >>>> With the annotation on the field, I am forced to have a reference to the >>>> ValueGetter, which might mislead programmers into using it - without the >>>> reference there I can just keep the cached values when the service arrives >>>> the first time and not have to document, etc that it might be null. >>> >>> The maven-scr-plugin ( and I think the ant task as well ) generates a >>> 'bindValueGetter' method automatically if you don't have it in your >>> class. If you implement it yourself, you can control its behaviour, >>> just like in your snippet above. >>> >>> Robert >>> >>>> >>>> Thanks, Dan. >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: [email protected] >>>> For additional commands, e-mail: [email protected] >>>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: [email protected] >>> For additional commands, e-mail: [email protected] >>> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [email protected] >> For additional commands, e-mail: [email protected] >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected]
