Re: [e4-dev] Annotations vs Events and when should we extend them ?

[Tom Schindl <tom.schindl@xxxxxxxxxxxxxxx>]

I started exploring this @Lifecycle stuff but made it now more generic
by using an injection named @Invoke

You can find my work at
https://github.com/tomsontom/eclipse.platform.runtime

Tom

Am 07.11.12 21:44, schrieb Tom Schindl:
> Hi,
> 
> First of all I think annotation should be used with great care here are
> the rules I'd set out for when to use them.
> 
> * when we need to get return value e.g. to cancel something
> 
> * if the information is very tightly scoped to the information provider
>   and many developers will make use it (performance!)
> 
> 
> IMHO lifecycle is better done with annotations, instead of events and
> the rest of the lifecycle is already annotation based.
> 
> A problem i have with the current annotation based system is that it is
> very static - we have to invent too many different annotation.
> 
> I much more love us to have 1 annotation named @Lifecycle but allow it
> to hold a meta value @Lifecycle("PROCESS_ADDITION"),
> @Lifecycle("PRE_SHUTDOWN"), ... and we have another invoke on the
> ContextInjectionFactory where we pass this meta value.
> 
> Such a feature would be very welcome to implement
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=392903 which has to based
> upon annotation because we need to have a return value, and using the
> event system is simply to cumbersom because the event is fired for each
> and every element and the receiver has to skip the processing in 95% of
> the cases (once more performance!).
> 
> Tom
> 
> Am 07.11.12 20:12, schrieb Eric Moffatt:
>>
>> While looking at https://bugs.eclipse.org/bugs/show_bug.cgi?id=376821I
>> realized that we should have some general guidelines for use in similar
>> situations...
>>
>> My general feeling is that we need to be strict(er) about annotations
>> since I'm afraid that they'll get out of hand otherwise but I really
>> don't have a particular metric in mind for deciding which technique we
>> should use. In the case of the defect above the choice was made easier
>> since it is clearly a UI Lifecycle event.
>>
>> Can anybody think of a 'rule' for deciding when we should use one versus
>> the other ?
>>
>> Eric
>>
>>
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>>
> 
> 


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