Re: [eclipselink-users] Object in EntityManager conext: no cache setting

[Tom Ware <tom.ware@xxxxxxxxxx>]

Hi Andrei,

  In the situation below, the cache settings will not be relevant.  When you 
have an entity that is in the managed state, (it is in the EM context), you will 
have to somehow do a refresh to get new data from that database - this is just 
the way JPA works.

  Aside from refresh and clear, you can use our query hints to cause a refresh:

http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_%28ELUG%29#Refresh

  This can be used in any query and additionally, in JPA 2.0 provided in the 
list of properties that in em.find(Class<T> entityClass, Object primaryKey,
                      Map<String, Object> properties)

  The scenario where you might want to play with the cache settings, is if in 
#3 you were using a different entityManager.  In that case, you should use the 
cache settings to disable shared caching.  See the "shared" setting on the Cache 
annotation here:

http://wiki.eclipse.org/Using_EclipseLink_JPA_Extensions_%28ELUG%29#Using_EclipseLink_JPA_Extensions_for_Entity_Caching

-Tom


Andrei Shakirin wrote:
> Hello everyone,
>  
> I need a short advice regarding EclipseLink cache settings.
>  
> Imagine the following situation:
> 1. JPA Client reads the entity using EntityManager. So entity becomes 
> into EM context.
> 2. Other external SQL client deletes this entity from the DB.
> 3. JPA Client reads the entity again using the same EM.
>  
> Question: are EM.refresh(entity) or EM.clear() only the ways to force EM 
> to re-read entity on step 3?
> Is it possible to achieve it also using any EclipseLink cache settings?
>  
> The following properties don't affect EM behavior in this case:
>                 <property name="_eclipselink_.cache.shared.default" 
> value="false"/>
>                 <property name="_eclipselink_.cache.type.default" 
> value="NONE"/>
>  
> Regards,
> Andrei.
>  
>  
>  
>
>
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