Hi James,
James Sutherland schrieb:
> That is odd. Could you please include the full stack trace to the exception.
> Also what about Timestamp locking does not work?
I'm not able to create a new entity with Timestamp, or any of the
wrappers, Long, Integer, Short using em.merge.
> It should work, as long as
> you use a valid timestamp type in the database that stores milliseconds
> correctly (what database and type are you using?).
>
Oracle Database 10g Express. The problem is actually not the optimistic
lock itself (=collisions), rather than the creation of new entities
using EntityManager#merge.
I'm not able to create a new Entity with any of the wrapper types.
> Is the object you are merging new or existing?
>
I only tested new one. There is only a problem with the wrapper types,
not the primitives. The workaround for the primitives is the initialization.
regards && thanks,
adam
>
>
> Adam Bien wrote:
>
>> Hi All,
>>
>> I'm testing now the optimistic concurrency behavior. All primitive
>> datatypes seems to work fine:
>>
>> @Entity
>> public class Entity{
>>
>> @Version
>> private int version;
>>
>> }
>>
>> @Entity
>> public class Entity{
>>
>> @Version
>> private long version;
>>
>> }
>>
>> etc.
>>
>>
>> However there is a problem with Long, Integer, Short, and bigger one
>> with Timestamp.
>>
>> It seems to be necessary to initialize the Wrappers, otherwise I get an
>> exception:
>>
>> "nested exception is: java.rmi.ServerException: RemoteException occurred
>> in server thread; nested exception is: java.rmi.RemoteException: null;
>> nested exception is: javax.persistence.OptimisticLockException:
>> Exception [TOPLINK-5010] (Oracle TopLink Essentials - 2.0.1 (Build
>> b03-fcs (04/05/2008))):
>> oracle.toplink.essentials.exceptions.OptimisticLockException Exception
>> Description: The object [Entity_at_1fc2f8c] cannot be merged because it has
>> changed or been deleted since it was last read. {3}Class> Entity"
>>
>>
>> already at the creation time.
>>
>> The workaround is simple - you have just to initialize the Wrapper at
>> creation time:
>>
>> @Entity
>> public class Entity{
>>
>> @Id
>> @GeneratedValue
>> private int id;
>> @Version
>> private Long version = new Long(0);
>>
>> }
>>
>>
>> The intiialization shouldn't be necessary: ...= new Long(0);
>>
>> With Timestamp it seems not to work in general...
>>
>> I'm creating the objects with em#merge and not em#persist,
>>
>> regards,
>>
>> adam
>>
>>
>
>
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> http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland
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>
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