Hi,
Say we have 2 entities person and Address where person class has an object
of class Address. Now, consider the case where I am persisting the person
object. There can be three mutually exclusive cases:
- If the corresponding Address object is persisted using the same entity
manager during the same transaction and entity manager is not closed till
now, than address entity is not detached till now. In this case find won't
be called.
- If we query for some address object and then set the corresponding
address field of the Person class using the result set of that query
object(assuming single result) in this case also, if the entity manager is
not closed till now then entity is not detached and find won't be called.
- In case where we are persisting Person and we have created Address
object in the same transaction but have not persisted it, then in this case
pcIsDetached() will return null as detached state is not known. In this case
find will be called and query will be fired to database to search for the
address entity.
- In case where entity manager is closed then pcIsDetached() will return
true as the entity is detached because of closing of entity manager. In this
case also find won't be called.
So, whenever we are not sure of the detached state of the object, then only
find is called.
thanks
On Sat, Jun 6, 2009 at 9:55 AM, Anurag Rai <
[hidden email]> wrote:
>
> Hi ,
> I want to understand why isDetached is using find. I thought it would be as
> simple as reading a boolean variable which is set if detach is caaled on
> that particular entity. Furthermore i am not getting the comment below:
>
> // not a part of Query result load. Look into the slices till found
> List<SliceStoreManager> targets = getTargets(fetch);
> for (SliceStoreManager slice : targets) {
> if (slice.initialize(sm, state, fetch, edata)) {
> assignSlice(sm, slice.getName());
> return true;
> }
> }
>
> Stack:
> DistributedJDBCStoreManager.initialize(OpenJPAStateManager,
> PCState, FetchConfiguration, Object) line: 399
>
> ROPStoreManager(DelegatingStoreManager).initialize(OpenJPAStateManager,
> PCState, FetchConfiguration, Object) line: 111
> ROPStoreManager.initialize(OpenJPAStateManager, PCState,
> FetchConfiguration, Object) line: 57
> DistributedBrokerImpl(BrokerImpl).initialize(StateManagerImpl,
> boolean, FetchConfiguration, Object) line: 996
> DistributedBrokerImpl(BrokerImpl).find(Object,
> FetchConfiguration, BitSet, Object, int, FindCallbacks) line: 954
> DistributedBrokerImpl(BrokerImpl).find(Object,
> FetchConfiguration, BitSet, Object, int) line: 876
> DistributedBrokerImpl(BrokerImpl).isDetached(Object) line: 4405
> SingleFieldManager.persist(OpCallbacks) line: 257
> StateManagerImpl.cascadePersist(OpCallbacks) line: 2962
> DistributedBrokerImpl(BrokerImpl).persist(Object, Object,
> boolean, OpCallbacks) line: 2561
> DistributedBrokerImpl.persist(Object, Object, boolean,
> OpCallbacks) line: 96
> DistributedBrokerImpl(BrokerImpl).persist(Object, OpCallbacks)
> line: 2383
> DelegatingBroker.persist(Object, OpCallbacks) line: 1039
> EntityManagerImpl.persist(Object) line: 681
> Main.main(String[]) line: 52
> --
> View this message in context:
>
http://n2.nabble.com/how-isDetached%28object%29-works--tp3034237p3034237.html> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>
>
--
Ashish Paliwal
Mobile : 9305128367
IIT Kanpur
India
