[jira] Commented: (OPENJPA-1692) Add post creation callback to BrokerFactory

["Pinaki Poddar (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/OPENJPA-1692?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12877608#action_12877608 ] 

Pinaki Poddar commented on OPENJPA-1692:
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This is an useful suggestion. The other usage of such post-initialization method hooks can be leveraged to construct some critical internal data structures (e.g. MetaDataRepository) that are often immutable after initialization. One can initialize these structures with thread guards and then drop the guards for entire lifetime. This pattern will provide an opportunity to scale/perform faster in multi-core environment.     
JPA does provide indicators such as <metadata-complete> etc to make such pattern. 

> Add post creation callback to BrokerFactory
> -------------------------------------------
>
>                 Key: OPENJPA-1692
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-1692
>             Project: OpenJPA
>          Issue Type: Bug
>          Components: kernel
>    Affects Versions: 2.0.0, 2.1.0
>            Reporter: Rick Curtis
>            Assignee: Rick Curtis
>
> There have been a couple instances (that come to my mind) where there was the need to do some work after creating the broker factory. Sometimes there is a necessity to ensure single threadedness @see (PersistenceProviderImpl.postBrokerFactoryInitialization(...)), other times we need to perform some additional configuration / initialization after the BrokerFactory has completed (openjpa.InitializeEagerly=true). 
> I recently ran across a problem with the second case. In AbstractBrokerFactory.ctor(...) we attempt to create a broker even though the subclassed BrokerFactory hasn't able to execute it's constructor.
> Example pseudo code:
> abstract class AbstractBrokerFactory {
> 	AbstractBrokerFactory(Config c){
> 		// setup
> 		if(InitializeEagerly==true)
> 			this.newBroker(); <-- BAD! The subclass hasn't executed it's constructor but it may be asked to create a new broker.
> 	}		
> }
> class ConcreteBrokerFactory extends AbstractBrokerFactory {
> 	Config _conf;
> 	ConcreteBrokerFactory (Config c){
> 		super(c);
> 		// setup
> 		_conf = c;
> 	}
> 	newBroker(){
> 		_conf.getSomething(); <-- _conf IS NULL because the constructor hasn't fully executed yet.
> 	}
> }
> I propose that we need a postCreationCallBack method on the BrokerFactory interface. This will be a single place that Bootstrap can drive this 'after creation ish' work.

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