Can anyone give a hibernate 2.1 example of how to map a class that implements two interfaces?

Provided below is how we're mapping a class that is implementing OrderableItem, but we're wanting to have Asset also implement BuilderAsset. We want to be able to use BuilderAsset in Hibernate just as we're able to use OrderableItem.

Do we have to include Asset as a joined-subclass in both mapping files? Is there a better way or a simpler way that I'm missing?

If anyone can point me in the right direction, thank you!

<hibernate-mapping>
<class name="collective.order.OrderableItem">
<id name="id" unsaved-value="null">
<generator class="native" />
</id>

<joined-subclass name="collective.md.image.Asset" table="Asset">
<key column="id" />
<set name="assetGroups" table="AssetGroupAssignments" cascade="none" inverse="true" lazy="true">
<key column="assetId" />
<many-to-many class="collective.md.image.AssetGroup" column="groupId" />
</set>

<list name="assetHistory" cascade="all" lazy="true">
<key column="asset_id"/>
<index column="i"/>
<one-to-many class="collective.md.image.AssetHistory"/>
</list>
<property name="copyOnly" />
<property name="dateUpdated" />
<property name="dateAdded" />
<property name="dateFileCreated" />
<property name="dateFileModified" />
<property name="deleted" />
<property name="expirationDate" />
<map name="fields" table="TypedField" cascade="all" lazy="true">
<key column="assetId"/>
<index column="keyName" type="string"/>
<one-to-many class="collective.md.image.TypedField"/>
</map>
<property name="filename" not-null="true" />
<property name="filepathMac" />
<property name="filepathUNC" />
<property name="filesize" />
<property name="merlotClass" />
<many-to-one name="metadata" class="collective.asset.Metadata" column="metadataId" cascade="save-update" outer-join="false" />
<property name="previewPixelWidth" />
<property name="releaseDate" />
<property name="imageInfoInitialized" />
<property name="imageInfo" length="8000" />
</joined-subclass>
</class>
</hibernate-mapping>

Does that even work? The class element:

doesn't have a "table" attribute. Isn't that required for the hbm.xml to validate?

As I see it, The question is meaningless.

A class implementing a set of interfaces have a flat structure. There are no any hierarchy. And there no any difference between this class mapping and the mapping of interface-less class with equivalent set of properties.

Suppose we have two inerfaces A and B mapped to different tables. There is some class C implementing both interfaces. I never tried such design, because I think the result to be unpredictable if we'll begin operating with C throw the Hibernate session (really result depends on implicit objects structure).