如何使用JPA对此建模？

RecordSources

long id

boolean preferred

Record

@OneToMany(cascade = CascadeType.ALL, fetch=FetchType.LAZY, mappedBy=\"record\")
private List<GenericSimpleRecordSource> recordSources;

GenericSimpleRecordSource

@Entity
public class GenericSimpleRecordSource implements Serializable
{
    public static enum Type {a,b}

    @ManyToOne private Record record;

    @NotNull
    private Type sourceType;

    @OneToOne(cascade = CascadeType.ALL,mappedBy=\"source\")
    private SimpleRecordSourceA sourceA;

    @OneToOne(cascade = CascadeType.ALL,mappedBy=\"source\")
    private SimpleRecordSourceB sourceB;
}

SimpleRecordSourceA

SimpleRecordSourceA

@Entity

@Entity
@Inheritance(strategy= InheritanceType.TABLE_PER_CLASS)
@DiscriminatorColumn(name=\"type\")
@DiscriminatorValue(\"generic\")
public class GenericRecordSource
{
   @Id @GeneratedValue(strategy=GenerationType.AUTO) private long id;
   @ManyToOne private Record record;
   private boolean preferred;
}

@Entity
@DiscriminatorValue(\"A\")
public class RecordSourceA extends GenericRecordSource
{
  ...
}

@Entity
@DiscriminatorValue(\"B\")
public class RecordSourceB extends GenericRecordSource
{
  ...
}

@OneToMany

@OneToMany(cascade = CascadeType.ALL, fetch=FetchType.LAZY, mappedBy=\"record\")
private List<GenericRecordSource> recordSources;