Illegal attempt to associate a collection with two open sessions

Hi,

I am taking data from one table and saving it on other, both the database are exact replica of each other.
So I am working with two hibernate sessions, and everything is working fine.
But when it comes to collection it throws this exception:

org.hibernate.HibernateException: Illegal attempt to associate a collection with two open sessions
at org.hibernate.collection.AbstractPersistentCollection.setCurrentSession(AbstractPersistentCollection.java:410)
at org.hibernate.event.def.WrapVisitor.processCollection(WrapVisitor.java:44)
at org.hibernate.event.def.AbstractVisitor.processValue(AbstractVisitor.java:101)
at org.hibernate.event.def.WrapVisitor.processValue(WrapVisitor.java:98)
at org.hibernate.event.def.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:55)
at org.hibernate.event.def.AbstractSaveEventListener.visitCollectionsBeforeSave(AbstractSaveEventListener.java:333)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:250)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:114)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:530)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:518)
at org.hibernate.impl.SessionImpl.save(SessionImpl.java:514)
at dms2dms.controller.DMS2DMSController.testCopy(DMS2DMSController.java:76)
at dms2dms.controller.DMS2DMSController.main(DMS2DMSController.java:25)

mapping file looks like this....
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
<class name="dms2dms.businessobject.DMSTitle" table="TITLE">
<id name="titleID" column="title_id" type="java.lang.Long">
<generator class="assigned" />
</id>
<property name="titleNumber" column="title_number" type="string"/>
<property name="authorisedBy" column="authorisation" type="string"/>
<property name="dateAuthorised" column="date_authorised" type="java.util.Date"/>

<many-to-one name="dmsCase" class="dms2dms.businessobject.DMSCase" column="case_id" cascade="all"/>
<many-to-one name="dmsOverlay" class="dms2dms.businessobject.DMSOverlay" column="overlay_id" cascade="all"/>

<set name="dmsMultiPart" table="multi_part" cascade="all">
<key column="title_id"></key>
<one-to-many class="dms2dms.businessobject.DMSMultiPart"/>
</set>

</class>
</hibernate-mapping>

I got it working by copying the Set before saving. Since collection is not synchronous thats why we need to do this acitvity

Hi, I'm having the same problem that you had. I understand that it's the saving of the set that is the problem but what do you mean by "copying the Set before saving"? Copy it how?

Thanks.

"Jboy JW"

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Thanks!
[ September 17, 2008: Message edited by: Paul Sturrock ]

Sorry, name updated. I still need help on this issue though.

Nevermind. I understand. You mean actually make a copy of the set in the code and use it to attach to the parent entity. And to make a copy of the set, I had to loop through each item of the set and add them to a new set to assign to the parent. Sweet.

Rather than looping, you could possibly evict the entity, so long as it is not loaded in a lazy fashion.

-Cameron McKenzie