Added field in enhanced vesrion of a class is not serialized. Hence the change
in detached+serialized instances is not registered under certain conditions.
-------------------------------------------------------------------------------------------------------------------------------------------------------------
Key: OPENJPA-151
URL: https://issues.apache.org/jira/browse/OPENJPA-151
Project: OpenJPA
Issue Type: Improvement
Components: kernel
Reporter: Pinaki Poddar
Assigned To: Pinaki Poddar
Enhancement adds a transient byte member field pcFlags to the class. This field
is originally used to optimize field access/mutation i.e. to short-circuit
mediation via StateManager under certain conditions (e.g. when the field is
part of the default fetch group). The field is transient, perhaps, to maintain
serialization compatibility. However, later changes such as
DetachedStateManager and improved attach strategies have made the usage of
these flag redundant.
This issue is a proposal to remove this field from the enhanced classes. The
proposed change is initiated by the following observation:
1. class A has one-to-one relation to class B
2. an instance a of A is related to b1 of B. b2 is another instance of B.
3. a, b1, b2 are detached, serialized, transported over the wire, desrialized
in a remote process as a*, b1* and b2*.
4. in the remote process a* is associated with b2*
5. a* is merged to the original process.
The change is not persisted when OpenJPA kernel is used with a JDO facade. It
works with JPA facade.
The initial analysis shows that the reason can be attributed to pcFlags and the
optimization in enhanced classes based on to its value. Because pcFlags is not
serialized, in a* instance pcFlags has a value of 0. Hence, the mutation of
a*'s relation to b2* from b1* is not mediated via the StateManager (yes, the
detached version was carrying its own StateManager). While merging the instance
a* back, it was adjudged clean while actually it was dirty. In JPA facade, the
enhancement process did not add the extra optimization for setter and so the
cloned owner instance was righly marked dirty.
Please note that if this proposal is accepted by the community, it will require
reenhancement of existing domain classes. The change will impact the internal
StateManager and PersistenceCapable API (essentally removal of certain methods
than any other behavioural change).
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
