MappedSuperclass - Change SequenceGenerator in Subclass
Yes, it is possible. You can override the default generator name with the @SequenceGenerator
annotation.
- Base class
@MappedSuperclass
public abstract class PersistentEntity implements Serializable
{
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "default_gen")
protected Long id = 0L;
public Long getId()
{
return id;
}
public void setId(Long id)
{
this.id = id;
}
}
Sequence (SQL)
create sequence role_seq;
Derived class
@Entity
@Table(name = "role")
@SequenceGenerator(name = "default_gen", sequenceName = "role_seq", allocationSize = 1)
public class Role extends PersistentEntity implements Serializable
{
private static final long serialVersionUID = 1L;
@NotNull
@Size(max = 32)
private String name;
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
}
- This approach worked fine in Hibernate 4.1.x, but it didn't in EclipseLink 2.x.
edit
- As per the comment, it seems to be working with EclipseLink 2.6.1-RC1.
In JPA that cannot be done with annotations. Annotation itself cannot be overridden. Entity inherits all the mapping information from MappedSuperClass. There is only two annotations that can be used to redefine mappings inherited from mapped superClass:
- AttributeOverride to override column mappings and
- AssociationOverride to override join columns / table.
Neither of them helps with GeneratedValue.
With EclipseLink, you can use a Customizer
. DescriptorCustomizer
interface defines a way to customize all the information about a jpa descriptor (aka a persistent entity).
public class SequenceCustomizer implements DescriptorCustomizer {
@Override
public void customize(ClassDescriptor descriptor) throws Exception {
descriptor.setSequenceNumberName(descriptor.getTableName());
}
}
and in your mapped superclass:
@MappedSuperclass
@Customizer(SequenceCustomizer.class)
public abstract class AbstractEntity implements Serializable {
...
}