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From "Paul Merlin (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (POLYGENE-129) @PreDestroy and @PostConstruct in lieu of initializable and service activation
Date Sun, 26 Feb 2017 13:07:45 GMT

    [ https://issues.apache.org/jira/browse/POLYGENE-129?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15884741#comment-15884741

Paul Merlin commented on POLYGENE-129:

{{Initializable}} has a single {{initialize()}} method, called on fragment instantiation ;
the {{@PostConstruct}} semantic apply well here.

{{Lifecycle}} has {{create()}} and {{remove()}} methods, called respectively  on *entities*
creation and removal from UoW ; {{@PostConstruct}} and {{@PreDestroy}} semantic apply well
here too.

{{@PreDestroy}} on a fragment would be ignored if not part of an entity

{{Activation}} has {{activate()}} and {{passivate()}} methods ; the semantic here is that
a passivated service can be reactivated ; {{@PreDestroy}} sounds a bit aggressive in this
context and {{@PostConstruct}} doesn't make sense for re-activation that happens on an existing

We should definitely replace {{Lifecycle}} and {{Initializable}} with these annotations.
I'm not sure about {{Activation}}, mostly because of semantics, any thoughts?

> @PreDestroy and @PostConstruct in lieu of initializable and service activation 
> -------------------------------------------------------------------------------
>                 Key: POLYGENE-129
>                 URL: https://issues.apache.org/jira/browse/POLYGENE-129
>             Project: Polygene
>          Issue Type: Improvement
>            Reporter: Niclas Hedhman
> Kent wrote on mailing list;
> {quote}
> I agree that the mix and match between composites and mixin declarations of the same
@Activators concept might lead to confusion - not a good idea.
> But a whole new thought .... aren't we reinventing the wheel here.
> We have Initializable interface - declaring a method (on the mixin) invoked after construction.
We have ServiceActivation - with 2 initialize/destroy methods implemented by a mixin - and
sort of referenced from the declarations on the composites.
> We have @Activators -- that may be declared on the composite - with wide flexibility
> But .... the JDK already has @PostConstruct and @PreDestroy annotations. These were originally
JEE stuff, but have been in the JDK for several years. And it is the same thing! Keeping a
special Initializable interface is, frankly, a quite dated way of doing stuff.
> I would say we should add support for declaring @PostConstruct and @PreDestroy on Mixins
- and support for @PostConstruct on plain objects (instantiated by ObjectFactory). And simply
remove (or just deprecate) Initializable and ServiceActivation alltogether.
> I am more uncertain whether the @Activators should be kept or not. On one hand I cannot
find a single usage in the whole codebase using beforeActivation and afterPassivation - so
not sure anyone would miss those features.
> On the other hand it might be handy to be able to reuse the same activation logic across
several composites - And there could be some potential of reusing the Activator as a listener
for UnitOfWork activation/passivation instead of module activation/passivation. The afterPassivation
could have some usages in that context.
> So I think we should keep that concept for now.
> {quote}

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