Re: [cdi-dev] Support Request (and Conversation?) Scope in @Singleton @Startup @PostConstruct methods
On 15/03/2012, at 10:26 PM, Mark Struberg wrote:
Simply as that: as the EntityManager per spec doesn't implement
Serializable.
Also the EJB spec explicitely states it as well in Section 4.2:
> - A container must not passivate a stateful session bean with an extended
> persistence context unless ...
Thus an Extended EM doesn't need to be Serializable. If you build a feature based on
the assumption that each EntityManager is Serializable, then it will result in
non-portable behaviour.
Well, in JPA-1 it would at least have been possible to implement a Serializable EM, but
in JPA2 you are mostly out of luck.
There are tons of indicators. As an example: how would you serialize an EntityManager
which holds a pessimistic lock() on the database? ^^
If you are holding a lock longer that a request you are doing something wrong. As you are
probably not going to want to serialise the entity manager in the middle of a request it
should be possible to work around it.
Also not everyone uses HA clusters or persistent sessions, so the conversation scope is
not always actually serialised.
There are still a lot of use cases for this, but it obviously there are limitations.
Stuart
LieGrue,
strub
----- Original Message -----
> From: Christian Bauer <christian.bauer(a)gmail.com>
> To: cdi-dev(a)lists.jboss.org
> Cc:
> Sent: Thursday, March 15, 2012 9:18 AM
> Subject: Re: [cdi-dev] Support Request (and Conversation?) Scope in @Singleton
@Startup @PostConstruct methods
>
>
> On Mar 6, 2012, at 2:58 , Mark Struberg wrote:
>
>> The EM is per JPA spec NOT Serializable and thus must not get stored in the
> Session.
>
> Chapter and section?
>
>
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