I’m stuck with a pre-defined object model and database schema and cannot get the Hibernate mapping to work.

Example of my pre-defined Object Model

public class Provider {
private long providerId;
private String comment;
private Signature signature;
private String issueDate; }

public abstract class Signature {
}

public class SignatureText extends Signature {
private String text; }

public class SignatureOther extends Signature {
private String other;
private String authority; }

public class SignatureSecondary extends Signature {
private String secondary;
private String permission;}

Example of my pre-defined database schema

PROVIDER_TABLE::
Provider_Id : NUMBER
Comment: VARCHAR2
Signature_Text: VARCHAR2
Signature_Other: VARCHAR2
Signature_Authority: VARCHAR2
Signature_Secondary: VARCHAR2
Signature_Permission: VARCHAR2
Issue_Date: TIMESTAMP

I’m only stuck on trying to map the Signature part of this model and cannot change the object model nor the database schema.

Please provide an example for this mapping if it is at all possible.