On Aug 2, 2010, at 11:57 AM, James Strachan wrote:
> On 2 August 2010 10:36, Paul Sandoz <Paul.Sandoz_at_oracle.com> wrote:
>> Hi James,
>>
>> You are correct, nothing is mentioned in the spec, although i
>> expected it
>> should.
>>
>> IIRC the reason why we did not perform injection on non-null field
>> values is
>> because they could have been set by the constructor or at
>> initialization,
>> and the time we considered it better not to overwrite something
>> that was
>> already set by the developer.
>>
>> I did a quick test with Guice and it overwrites fields.
>
> Spring does the same too if you annotate the field. Its no different
> really from having default fields and then doing property injection in
> spring to override a property value (after the constructor has been
> called).
>
>
>> So perhaps we could
>> relax this constraint and the developer should take care mixing
>> injection
>> declarations that could results in IoC frameworks fighting over an
>> injection
>> target?
>
> Agreed.
>
> Each annotation should only be injected by one IoC framework (i.e. an
> annotation is a JAXRS annotation or a Guice or Spring one etc); for
> injection points which are optional (e.g. a @QueryParam may be
> specified in a request or it might be absent) - then the field/method
> injection may occur or not. This is similar to having a bean in Spring
> where the bean might have a property injected or not (based on the IoC
> configuration).
>
> When an injection point is optional its useful to be able to provide a
> default value in case the injection does not occur - but its totally
> fine for the injection to override the value.
>
> I've raised an issue for this:
> https://jersey.dev.java.net/issues/show_bug.cgi?id=564
>
Thanks. This should be an easy fix :-)
Paul.