I don't really have to do like that. Your solution is more clean and I will
use it. Thanks.
But for learning purpose, I've used some others methods.
I don't know why i can't update a children reference per another.
In fact, the new object is in the datastore. When I manually delete the
first reference, the parent now refer his new children. Weird.
2011/1/4 Stephen Johnson <onepagewo...@gmail.com>
> Why do you have to delete the location entity? Why not just update the
> current location entity with the new coordinates? That would be much
> more efficient.
>
>
> On Tue, Jan 4, 2011 at 10:20 AM, yoyo <yoyomo...@gmail.com> wrote:
>
>> The update still don't works. I give up.
>>
>> I use the "@Persistent(dependent = "true")" and add the delete instruction
>> when I update the user location, in a transaction.
>> Now it works, but I think it's not very clean/efficient.
>>
>> Have a nice day.
>>
>> public void updateUserLocation(String username, Location newLocation) {
>> PersistenceManager pm = PMF.getPersistenceManager();
>> Transaction tx = pm.currentTransaction();
>> try {
>>
>> // Get the user and update the location
>>
>> tx.begin();
>> POJOUser user = pm.getObjectById(POJOUser.class, username);
>> pm.deletePersistent(user.getLastLocation());
>> user.setLastLocation(new POJOLocation(newLocation));
>> tx.commit();
>>
>> } catch (JDOObjectNotFoundException ex) {
>>
>> } finally {
>>
>> if (tx.isActive()) {
>> tx.rollback();
>> }
>> pm.close();
>> }
>> }
>>
>> @PersistenceCapable
>> public class POJOUser {
>>
>> /** Primary key */
>> @PrimaryKey
>> @Persistent
>> private String key = null;
>>
>> /** Username */
>> @Persistent
>> private String username = null;
>>
>> /** Password */
>> @Persistent
>> private String password = null;
>>
>> /** The last location of the user */
>> @Persistent(dependent = "true")
>> private POJOLocation lastLocation = null;
>> ...
>> }
>>
>> @PersistenceCapable
>> public class POJOLocation implements Location {
>>
>> /** Primary key */
>> @PrimaryKey
>> @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
>> private Key key = null;
>>
>> /** X */
>> @Persistent
>> private Double x = null;
>>
>> /** Y */
>> @Persistent
>> private Double y = null;
>> ....
>> }
>>
>>
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