AnyDiscriminatorValues ignore unknown discriminators?

Hibernate ORM
1

I am trying to map an existing database with a discriminator and id column. However, certain values for the discriminator column have null or empty string - basically there is nothing to look up for certain discriminator values.

Is there a way for me to tell hibernate to return NULL for an @Any property when there is an unknown discriminator values?

Example:

TABLE_WAYPOINT

WPID LAT LON
WP_1 … …

TABLE_BEACON

BCID LAT LON
BC_1 … …

TABLE_SEGMENT

SEGID FIX_TYPE FIX_ID
SEG_1 WAYPOINT WP_1
SEG_2 BEACON BC_1
SEG_3 NOTMAPPED 
...
class Segment {

   @Any
   @AnyDiscriminator(DiscriminatorType.STRING)
   @AnyKeyJavaClass(String.class)
   @JoinColumn(name="fix_id", nullable=true)
   @Column(name="fix_type", nullable=true)
   @AnyDiscriminatorValues({
      @AnyDiscriminatorValue(discriminator = "WAYPOINT", entity = Waypoint.class),
      @AnyDiscriminatorValue(discriminator = "BEACON", entity = Beacon.class)
      // IGNORE EVERYTHING ELSE!!!
   })
   Cartographic fixPoint; // should read the lat/lon of the fix type, or be null if an invalid fix type

}
2

I was able to hack it so that it “works”…

// Cannot use @mappedsuperclass or it throws errors
class Cartographic {
    Double lat;
    Double lon;
}

class Beacon extends Cartographic {
    // have to re-declare these, or they return null
	Double lat;
	Double lon;
}

class Waypoint {/*same...*/}

class Segment {

   @Any(fetch=FetchType.LAZY, optional=true) // only by setting both lazy and optional does it do the lookup without errors.
   @AnyDiscriminator(DiscriminatorType.STRING)
   @AnyKeyJavaClass(String.class)
   @JoinColumn(name="fix_id", nullable=true)
   @Column(name="fix_type", nullable=true)
   @AnyDiscriminatorValues({
      @AnyDiscriminatorValue(discriminator = "WAYPOINT", entity = Waypoint.class),
      @AnyDiscriminatorValue(discriminator = "BEACON", entity = Beacon.class)
      @AnyDiscriminatorValue(discriminator = "NOTMAPPED", entity = BogusEntity.class)  // still have to have an entity for the discriminator value, but it can be bogus
   })
   Cartographic fixPoint; // should read the lat/lon of the fix type, or be null if an invalid fix type

}
3

@Jesse_Shaffer glad you were able to work around it, there is no option to default to null when not matching any discriminators I’m afraid. This could be a new feature request, feel free to open one at our issue tracker.

We have something similar in org.hibernate.annotations.AnyDiscriminatorImplicitValues + a custom org.hibernate.metamodel.spi.ImplicitDiscriminatorStrategy, but still I believe you will be required to always specify an EntityMappingType (though that could be your “wrapper” entity for unknown values).