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https://issues.apache.org/jira/browse/DELTASPIKE-940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15110905#comment-15110905
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Gerhard Petracek edited comment on DELTASPIKE-940 at 1/21/16 5:03 PM:
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[~thomashug] and [~kalgon] :
that isn't the whole story. @Transactional#qualifier is not intended to be used
for the main use-case. it's just in place for an optimization.
with @Transactional#qualifier you can limit the transactions to start.
without it all injected entity-managers will be used (for each entity-manager a
transaction will get started).
for those entity-managers there is no qualifier limitation in theory (currently
it's limited to qualifier-types to improve the performance, but it's just an
implementation detail of EntityManagerEntry and not a limitation of the api).
it's the other way round: EntityManagerResolver is limited, because there can
be only one active entity-manager (in case of the data module it's just a minor
limitation due to the overall concept).
was (Author: gpetracek):
[~thomashug]:
that isn't the whole story. @Transactional#qualifier is not intended to be used
for the main use-case. it's just in place for an optimization.
with @Transactional#qualifier you can limit the transactions to start.
without it all injected entity-managers will be used (for each entity-manager a
transaction will get started).
for those entity-managers there is no qualifier limitation in theory (currently
it's limited to qualifier-types to improve the performance, but it's just an
implementation detail of EntityManagerEntry and not a limitation of the api).
it's the other way round: EntityManagerResolver is limited, because there can
be only one active entity-manager (in case of the data module it's just a minor
limitation due to the overall concept).
> @Transactional and @EntityManagerConfig each use a different method to
> resolve EntityManagers
> ---------------------------------------------------------------------------------------------
>
> Key: DELTASPIKE-940
> URL: https://issues.apache.org/jira/browse/DELTASPIKE-940
> Project: DeltaSpike
> Issue Type: Improvement
> Components: Data-Module, JPA-Module
> Reporter: Xavier Dury
> Assignee: Thomas Hug
> Priority: Minor
>
> When an application uses multiple {{EntityManager}}'s, there must be a way to
> specify which one(s) should be used. Currently, {{@Transactional}} and
> {{@EntityManagerConfig}} use different approaches:
> - {{@Transactional}} can take one or more qualifiers directly in its
> {{qualifier()}} member ({{@Transactional(qualifier = MyDB.class)}})
> - While {{@EntityManagerConfig}} must define an {{EntityManagerResolver}}
> ({{@EntityManagerConfig(entityManagerResolver =
> MyDBEntityManagerResolver.class}})
> I think both should be unified and use a single way to specify which
> {{EntityManager}} to use. IMHO, the {{@Transactional}} way of doing looks
> better and should be applied to {{@EntityManagerConfig}}.
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