In my design I have two entities...

Code:
public class BuildingDesign { 
   .... 
   private int fID; 
   private String fTitle; 
   .... 
} 

public class BuildingDesignLock { 
   ... 
   private int fLockID; 
   private int fBuildingDesignID; 
   private String fUserID; 
   ... 
} 

CREATE TABLE `building_design` ( 
  `BuildingDesignID' int(11) NOT NULL auto_increment, 
  `BuildingDesignTitle` varchar(50) NOT NULL, 
  PRIMARY KEY  (`BuildingDesignID`), 
) 

CREATE TABLE `building_design_lock` ( 
  `LockID' int(11) NOT NULL auto_increment, 
  `BuildingDesignID' int(11) NOT NULL, 
  `LockUserID` varchar(50) NOT NULL, 
  PRIMARY KEY  (`LockID`), 
  UNIQUE KEY `BuildingDesignID (`BuildingDesignID`))
A 'building design' can be created independent of its related lock entity. The 'lock' entity is optional and used to hold the name of a user that has placed a write lock over a building design entity.

There is a 1 to 1/0 link (i.e. optional one-to-one) link from BuildingDesign to BuildingDesignLock.

I want to extract a list of the building designs with their lock status. For this I've created a descendant class like...

Code:
public class BuildingDesignInfo extends BuildingDesign { 
   .... 
   private BuildingDesingLock fLock; 
   .... 
}
I want to create a Hibernate mapping for this 'BuildingDesignInfo' class, but I can't find an example of a one-to-one mapping where the link is a foreign key in the second table.

Can this be done?