If this has been answered, pls post link as I've done my searches and gone through the manuals.

I wonder if this is possible to map:

Class Activity points to a collection of Address subclasses twice, e.g. Activity has two Sets: one for internalAddresses one for externalAddresses each of which contain a set of Address subclasses.

I was hoping to use "Table per Concrete class" inheritance mapping, but I'm coming unstuck because I've got two arrays to populate on Activity. I keep getting :

net.sf.hibernate.WrongClassException: Object with id: 1 was not of the specified subclass: com.simon.dao.InternalAddressesDo (loaded object was of wrong class)
at net.sf.hibernate.loader.Loader.instanceAlreadyLoaded(Loader.java:455)

Please advise if how I should approach this, as I've tried using polymorphism, discriminator-value attributes, but seem to always hit a wall because of the two foreign keys.

Thanks

I solved it. FYI:

I needed to add the 'discriminator-value' on the subclass element on the many side hbm.xml as well as a 'where' attribute on the parent mapping. (It's the parent side that I kept missing)

Child:

<class name="com.simon.dao.AddressDo" table="ADDRESS">

<id name="id" column="UID" type="long" unsaved-value="0">
<generator class="increment"/>
</id>
<discriminator type="string" column="type"/>
<property name="displayName" column="DisplayName" not-null="true" />
<property name="emailAddress" column="EmailAddress" not-null="true" />
<property name="firstName" column="FIRSTNAME" not-null="true"/>
<property name="lastName" column="LASTNAME" not-null="true"/>
<many-to-one class="com.simon.dao.ActivityDo"
name="activity"
column="activity_id"
/>
<subclass name="com.simon.dao.InternalParticipantDo" discriminator-value="INT" >
</subclass>
<subclass name="com.simon.dao.ExternalParticipantDo" discriminator-value="EXT">
</subclass>

</class>

PARENT:

<class name="com.simon.dao.ActivityDo" table="ACTIVITY" >
<id name="id" column="UID" type="long" unsaved-value="0">
<generator class="increment"/>
</id>
<property name="value" column="value" not-null="false"/>

<set name="internalCCParties" cascade="all" inverse="true" where="type='INT'">
<key column="activity_id"/>
<one-to-many class="com.simon.dao.InternalParticipantDo"/>
</set>

<set name="safParticipants" cascade="all" inverse="true" where="type='EXT'">
<key column="activity_id"/>
<one-to-many class="com.simon.dao.ExternalParticipantDo"/>
</set>

</class>