[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-5024) MetadataContext#registerAttribute does not recognize inherited fields

[Steve Ebersole (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-5024?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=45233#comment-45233 ] 

Steve Ebersole commented on HHH-5024:
-------------------------------------

So the tests I created from these issues show what we think are 2 different "issues".  

First, the specific case Hardy and I were discussing above which came originally from Alexis.  We both agree this is just incorrect mapping.  Specifically, attributes defined on a {{MappedSuperclass}} can be "overridden" on an entity sub class, but the proper way to do that is to use ((AttributeOverrides)).  And there is no spec provided way to say that a basic attribute defined on a {{MappedSuperclass}} become {{Id}} mappings on an entity sub class.  Given that model, we think the correct way to map that to match the intent and meet the spec is to mark those 2 attributes as {{Transient}} on the {{MappedSuperclass}} like so:
{code:title=AbstractAttribute.java|borderStyle=solid}
@MappedSuperclass
public abstract class AbstractAttribute implements Serializable {
    protected String key;
    protected String value;

    public AbstractAttribute() {
        super();
    }

    @Transient
    public abstract String getOwner();

    @Transient
    public String getKey() {
        return key;
    }

    public void setKey(String key) {
        this.key = key;
    }

    @Column(name = "attribute_value")
    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}
{code}

The entity class stays as it was.  And this works in terms of both the metamodel generator and Hibernate populating that static metamodel.

----

The second issue deals with "embeddable" classes defined on a {{MappedSuperclass}}.  This holds true for both {{Embedded}} and {{EmbeddedId}}.  The issue is the way in which support for {{MappedSuperclass}} was originally "bolted on" to the existing Hibernate {{PersistentClass}} mapping classes.  Changing the {{getDeclaredField}} call to {{getField}} as suggested here is really just a band aid.  But we will make that change for embeddable attributes for 4.1 as better solutions are already targeted for 5.0

> MetadataContext#registerAttribute does not recognize inherited fields
> ---------------------------------------------------------------------
>
>                 Key: HHH-5024
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5024
>             Project: Hibernate ORM
>          Issue Type: Bug
>          Components: entity-manager, metamodel
>    Affects Versions: 3.5.0-CR-2, 3.5.1, 4.0.0.Final
>         Environment: Hibernate 3.5.0-CR-2, JPA Modelgen 1.0.0-CR-1
>            Reporter: Adrian Hummel
>            Assignee: Steve Ebersole
>             Fix For: 4.1.0
>
>         Attachments: bugreport.zip, hhh-5024.zip, hhh-5024.zip
>
>          Time Spent: 6.85h
>
> The embeddable class {{CustomerId}} (see attached ZIP) inherits from the base class {{AbstractIdentity}} (annotated with {{@MappedSuperclass}}). The metamodel classes for these two classes are correctly generated:
> {code:title=AbstractIdentity_.java|borderStyle=solid}
> import javax.persistence.metamodel.SingularAttribute;
> import javax.persistence.metamodel.StaticMetamodel;
> @StaticMetamodel(AbstractIdentity.class)
> public abstract class AbstractIdentity_ {
> public static volatile SingularAttribute<AbstractIdentity, String> id;
> }
> {code}
> and
> {code:title=CustomerId_.java|borderStyle=solid}
> import javax.persistence.metamodel.StaticMetamodel;
> @StaticMetamodel(CustomerId.class)
> public abstract class CustomerId_ extends AbstractIdentity_ {
> }
> {code}
> When building the entity manager factory, {{MetadataContext#registerAttribute}} (line 378) tries to resolve the field {{CustomerId_.id}} using {{Class#getDeclaredField}}. This results in a {{NoSuchFieldException}} because the field is declared in the super class {{AbstractIdentity_}}.
> Proposed solution: Since all field declarations in the metamodel are public, the {{Class#getField}} method should be used instead.

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