From: Markus Fuchs <Markus.Fuchs_at_Sun.COM>
Date: Thu, 02 Aug 2007 16:55:25 -0700

Hi Jeffrey,

Jeffrey Blattman wrote:

thanks markus,

this gets me further. the complexity is this, i essentially have three entities

1. Page
2. Portlet
3. Preferenence

simple right? a page contains a portlet contains preferences. a delete / update / etc of Page should affect all its portlets, and a delete / update / etc of a portlet should affect its preferences. each of these has a name.

to model the containment, Portlet's ID is the page name + it's own name (PortletId). that one is simple. however, when we go a level deeper to Preference, Preference's ID is the Portlet's ID + it's own name (PreferenceId).

how do i model that? PortletId is *not* a simple type, so I can't use it as an @Id field in Preference. how do i define Preference's ID fields?

Id fields:

In page: pageId
In Portlet: pageId & portletId, IdClass has pageId & portletId fields
In preference: pageId & portletId & preferenceId, IdClass has pageId & portletId & preferenceId fields

i tried what you suggested in Preference

    @Id
    @Column(nullable = false, name="PORTLET_ID")
    private String portletId = null;
   
    @ManyToOne(optional = false, cascade = CascadeType.ALL)
    @Column(insertable=false, updatable=false, nullable=false, name="PORTLET_ID")
    private Portlet portlet;

but i get this:

Exception Description: Entity class [class com.sun.portal.pom.Preference] must use a @JoinColumn instead of @Column to map its relationship attribute [entity].

It must of course be @JoinColumn

when i just make it a @JoinColumn instead,

    @ManyToOne(optional = false, cascade = CascadeType.ALL)
    @Column(insertable=false, updatable=false, nullable=false, name="PORTLET_ID")
    @XmlTransient
    private Portlet portlet;

i get this ...

Exception Description: The @JoinColumns on the annotated element [private com.sun.portal.pom.Entity com.sun.portal.pom.Preference.entity] from the entity class [class com.sun.portal.pom.Preference] is incomplete. When the source entity class uses a composite primary key, a @JoinColumn must be specified for each join column using the @JoinColumns. Both the name and the referenceColumnName elements must be specified in each such @JoinColumn.

Looks like you used @JoinColumn*s*. Please check.

what am i supposed to use for the join columns? since PortletId encapsulates both the Page name and Portlet name, why does it want to to specify more than that?

i feel like i must be making this more complicated than it needs to be. all i want is to model some objects containing other objects where all operations cascade.

This should be doable. First start with the Page and Portlet classes. When this works, add Preferences and model the relationships and IdClass accordingly.

-- markus.

?

Markus Fuchs wrote:

Hi Jeffrey,

Entities should not use relationship fields as part of the primary key. The JPA spec says (please see 2.1.4.):

The primary key (or field or property of a composite primary key) should be one of the following types:
any Java primitive type; any primitive wrapper type; java.lang.String; java.util.Date;
java.sql.Date.

Try changing:

public abstract class Entity implements Serializable {
    @Id
    @Column (nullable = false, name="ENTITY_NAME")
    @XmlAttribute
    private String name;

    @Id
    @Column (nullable = false, name="PAGE_ID")    
    private String pageId;


    @Column (nullable = false, name="PAGE_ID")    
    @ManyToOne (cascade = CascadeType.ALL, insertable=false, updatable=false)
    private Page page = null;
...
}

public class EntityId implements Serializable {
    private String name;
    private String pageId;
...
}
   
  

-- markus.

Entity
Jeffrey Blattman wrote:

hi,

2.0-b56, i'm seeing this ...

Exception Description: Invalid composite primary key specification. The names of the primary key fields or properties in the primary key class [com.sun.portal.pom.EntityId] and those of the entity bean class [class com.sun.portal.pom.Entity] must correspond and their types must be the same. Also, ensure that you have specified id elements for the corresponding attributes in XML and/or an @Id on the corresponding fields or properties of the entity class.

i've attached the two classes. Entity has IDs name and page, and EntityId has fields name and page. same name, same type. i can zip the maven2 project so the problem can be reproduced, if that helps.

what am i missing?

thanks.