Hi there,

The case is there is a immutable class A (table T_A) and it has a list of mutable class B (table T_B). When class A gets persisted, only the new or modified instances in the list of class B will be inserted or updated in T_B. T_A will not get affected.
Somehow, I need to use <union-subclass ....> to map a class A to a table T_A and use <bag ...> to map a list of class B in class A's mapping file. Because T_A is immutable. a custom peresister class is created that extends from UnionSubclassEntityPersister and its isMutable() method returns false. When Hibernate loads the class A, its status is set to READ_ONLY.
In the business processing, some new instances of class B are added to the list in the class A. However, when the session gets flushed, Hibernate will check the status of the class A in AbstractFlushingEventListener.prepareEntityFlushes (...). In this method, only the status of MANAGED or SAVING will get flushed. Class A will not get flush because its status is READ_ONLY. The new instances of class B in the list will not get inserted into table T_B.
What is the right solution to this case? How can I update or insert B into T_B only without affect A?
I will appreciate for any help.

Thanks.

I did some tests for both custom persister and mutable attribute. Whatever isMutable() returns false or mutable="false", Hibernate will mark the status of entity A as READ_ONLY. When the session starts flush, Hiberate checks the status of the entity A in AbstractFlushingEventListener.prepareEntityFlushes(). Usually, if the status of an entity is MANAGED or SAVING, Hiberdate will go further and detect if there is TRANSIANT objects in the graph. If the status is READ_ONLY, Hibernate will skip this step.
In my case, entity A is READ_ONLY, then, the new entities added in the graph will not be detected and will not be inserted into T_B.

Can Hibernate team help it out?

Thank you very much.