JPA 2 XML Mapping of Embedded so that it worked with Hibernate Meta model generator

Question

I want to use JPA 2 Meta model generator for Hibernate (Version 1.1.1-Final) (in a Spring Application). Because I use a Mapped Superclass which is the base for all Entities, and this class is located in an different jar (for reuse) I need to map this class explicit in XML (only for the meta model generation, because it works without any additional stuff on time) --- May somebody has a hint how to solve this in general, but it is not the question.

This mapped Super class (BusinessEntity) uses an Embedded class (BusinessId).

@SuppressWarnings("serial")
@MappedSuperclass
public abstract class BusinessEntity<T extends Serializable>
                      implements Serializable {
   @Id    
   @GeneratedValue(strategy = GenerationType.AUTO)
   @Column(name = "id")
   private Long id;

   @Embedded
   private BusinessId<T> businessId;
 ...
}


@Embeddable
public class BusinessId<T> implements Serializable {
    @Column(nullable = false, unique = true, name = "businessId")
    private long businessId;
  ...
}

But I do not get the mapping working together with the Generator: If I use this orm.xml

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm
    http://java.sun.com/xml/ns/persistence/orm_2_0.xsd"
    version="2.0">

    <mapped-superclass class="BusinessEntity"  
            access="FIELD">     
        <attributes>            
            <id name="id">
                <column nullable="false"/>
                <generated-value strategy="AUTO"/>              
            </id>
            <embedded name="businessId"/>
        </attributes>       
    </mapped-superclass>

    <embeddable class="BusinessId"
            access="FIELD">
        <attributes>
            <basic name="businessId">
                <column nullable="false" unique="true"/>
            </basic>
        </attributes>
    </embeddable>   
</entity-mappings>

The Generator create this two Files:

@StaticMetamodel(BusinessEntity.class)
public abstract class BusinessEntity_ {
    public static volatile SingularAttribute<BusinessEntity, Long> id;
}

@StaticMetamodel(BusinessId.class)
public abstract class BusinessId_ {
    public static volatile SingularAttribute<BusinessId, Long> businessId;
}

You can see, the embedded field businessId in BuinessEntity_ is missing!

When I replace the <embedded name="businessId"/> by <basic name="businessId" /> the Generator create this uncompilable class (The Generic T can not been resolved).

@StaticMetamodel(BusinessEntity.class)
public abstract class BusinessEntity_ {

    public static volatile SingularAttribute<BusinessEntity, Long> id;
    public static volatile
           SingularAttribute<BusinessEntity, BusinessId<T>> businessId;
}

So my Question is how to map the stuff correct? -- Or is there a better way in general?

Answer 1

<basic> cannot be used for complex types. You must use <embedded>. I have also experienced shortcomings in the annotation processor when applied to orm.xml.

I have submitted this issue a while back (February 18th):

http://opensource.atlassian.com/projects/hibernate/browse/METAGEN-57

Which has not been looked at yet. It seems that it isn't given that much attention as the processor is working for annotations.

I suggest that you submit an issue for your problems as well.