[sakai2-tcc] Annotation based injection within Sakai components

[Steve Swinsburg]

There have been previous breaking API changes, specifically when a new class/method is introduced and tools then use it, which mean they cannot be used in older versions.

One that comes to mind is the ActivityService API which was added in Kernel 1.2, and Profile2 1.4+ use it, so you cannot use Profile2 1.4 in Sakai 2.7 or previous.[1] 

I think at some point we need to be able to make choices that move us forward, sometimes at the expense of tool or legacy code that cannot keep up. It would certainly highlight code which is unsupported but just hanging on. So I'd be all for incorporating a number of additional changes as David lists, so that it's all out of the way at once.

Making this change would theoretically mean that a tool wouldn't need to worry about XML wiring and they can just get busy writing code. It's a small improvement, but it's really useful. The other benefit is the combination with annotation based autowiring of dependencies in JUnit tests, which I have been unable to get working with a mix of Sakai specific components.xml and annotations. It's either one or the other.

cheers,
Steve

p.s. By the way, the lombok thing is easily done, in any layer since it is (mostly) a compile time annotation. I don't even use getters/setters anymore, they are so 2011.

[1] https://confluence.sakaiproject.org/display/PROFILE/Profile2+-+Version+Compatibility

On 16/05/2012, at 1:56 AM, David Horwitz wrote:

> If we are going to make a non-backward compatible kernel (i.e. Kernel 
> 2.0). We should consider other changes that are queued for this:
> 
> 1) Spring 3
> 2) Moving to the tomcat 6/7 classloader layout
> 3) Removal of deprecated API methods
> 4) anything I missed?
> 
> D
> 
> On 05/15/2012 05:39 PM, John Bush wrote:
>> what specifically is going to break backwards compatibility ?
>> 
>> On Mon, May 14, 2012 at 7:17 PM, Steve Swinsburg
>> <steve.swinsburg at gmail.com>  wrote:
>>> Hi all,
>>> 
>>> I've just filed a feature request for annotation based injection within Sakai components. Currently it is not possible and changes need to be made to the kernel to do this:
>>> https://jira.sakaiproject.org/browse/KNL-923
>>> 
>>> In discussions with Aaron, this is a relatively simple job, but will be a backwards incompatible change. I'm interested to know more about this and to get the discussion going.
>>> 
>>> Also interested to know if the incompatibility means that:
>>> 
>>> 1. You won't be able to use a newer kernel in an older version of Sakai (ie you won't be able to use the 1.3 kernel for Sakai 2.9 in Sakai 2.8) - does anyone even do that?
>>> 2. Tools won't work.
>>> 
>>> thanks,
>>> Steve
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>> 
>> 
> 
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