Can JDO Query be extended

Question

Hi,
Does KODO provide a hook to extend the javax.jdo.Query's implementation
class from KODO, they way it supports extending PersistenceManagerImpl?
Most of my objects need to be transferred over wire, and they should have
their identity accessible from the object itself when it goes in a
different jvm. If I can extend the Query's execute() methods to populate
their id in the object itself, that would look like a cleaner and
transparent solution.
Suggestions?
Regards,
Manoj

Answer 1

Manoj-
JDO does a lazy fetching of objects A, when B.getA() is called. I need to
have "id" member variable of A also populated before returning the
collection.Hmm ... do you mean that you just want to populate an "id"
field when you load an instance of A? If that is all you are trying to
do, then I would suggest having your class implement
javax.jdo.InstanceCallbacks and doing that work in jdoPostLoad().
In article <[email protected]>, Manoj Prakash wrote:
class A{
int id
// other primitive members
Class B{
int id
HashSet a // collection of A
public Collection getA(){
return a;
When I query objects of class B, I can use the FacadeQuery the way you
suggested, to populate "id" member variable of B.
JDO does a lazy fetching of objects A, when B.getA() is called. I need to
have "id" member variable of A also populated before returning the
collection.
I wanted to know what method(s) if overridden in PersistenceManagerImpl
would provide me hook to do that.
Regards,
Manoj
Marc Prud'hommeaux wrote:
Manoj-
I'm not sure what you mean. Can you post some pesudo-code of what you
are trying to accomplish?
In article <[email protected]>, Manoj Prakash wrote:
Great, thanks.
What methods if overridden from PersistenceManagerImpl can take care of
the case of populating Ids for the objects in a Collection, during lazy
fetching?
Marc Prud'hommeaux wrote:
Manoj-
You can't directly extend our Query implementation, but you could always
extend PersistenceManagerImpl and extend all the methods that return
queries to wrap them in a ManojQueryFacade class that just does what you
want in the execute method before delegating the call to the internally
held query. I think that should work OK (although I haven't actually
tried it).
In article <[email protected]>, Manoj Prakash wrote:
Hi,
Does KODO provide a hook to extend the javax.jdo.Query's implementation
class from KODO, they way it supports extending PersistenceManagerImpl?
Most of my objects need to be transferred over wire, and they should
have
their identity accessible from the object itself when it goes in a
different jvm. If I can extend the Query's execute() methods to populate
their id in the object itself, that would look like a cleaner and
transparent solution.
Suggestions?
Regards,
Manoj
Marc Prud'hommeaux [email protected]
SolarMetric Inc. http://www.solarmetric.com
Marc Prud'hommeaux [email protected]
SolarMetric Inc. http://www.solarmetric.com
Marc Prud'hommeaux [email protected]
SolarMetric Inc. http://www.solarmetric.com