Hello,

Because I searched a lot, and I am happy to have found it, I want to share my code (even if it is just 'test code', so not very pretty). The Seam version is 2.11.GA.

In my application, I have an class 'Activite' (Activity). This class has two child : 'Production' and 'Inactivite' (Inactivity).

First, I have managed to deal with inheritance and EntityHome (the code is above), in SINGLE_TABLE mode.

I first code the classes, then generated whith seam-gen, then updated the pages (ProductionEdit.xhtml and ActiviteEdit.xhtml). I could edit one of 'Production' or 'Inactivite', with informations from their parent class (the two dates).

The table generated looks so :

agora-01=# \d activite
                Table "public.activite"
   Column    |            Type             | Modifiers
-------------+-----------------------------+-----------
 activite_id | integer                     | not null
 date_debut  | timestamp without time zone |
 date_fin    | timestamp without time zone |
 version     | integer                     |
 type        | integer                     |
 descriptif  | character varying(255)      |
 libelle     | character varying(255)      |
 role        | character varying(255)      |
Indexes:
    "activite_pkey" PRIMARY KEY, btree (activite_id)

The orders generated in my database looks like this (extract from my Postgresql database log) :

2009-03-10 10:08:22 CET LOG:  execute <unnamed>: update activite set date_debut=$1, date_fin=$2, version=$3, descriptif=$4, libelle=$5, role=$6 where activite_id=$7
2009-03-10 10:08:22 CET DETAIL:  parameters: $1 = '2009-03-02 00:00:00', $2 = '2009-03-03 00:00:00', $3 = NULL, $4 = 'data', $5 = 'data', $6 = 'zzzz', $7 = '254'

That's fine! I hope this could help someone else (I found some questions, but no answer in the forum).

Here is the code for the SINGLE_TABLE version :

First, the abstract class :

Activite.java

package com.sopra.academy.seam.agora.entity;

import java.util.Date;
import javax.persistence.Column;

(imports...)

import org.hibernate.validator.NotNull;
import org.jboss.seam.annotations.Name;

/*
 * Classe pour gestion de l'activité des collaborateurs
 */

@Entity

@Table(name = "activite")
@Inheritance(
strategy=InheritanceType.SINGLE_TABLE) 
@DiscriminatorColumn(name="type", discriminatorType=DiscriminatorType.INTEGER) 

public abstract class Activite implements java.io.Serializable {
     private static final long serialVersionUID = 1L;


     private Integer id; // identifiant primaire
     private Integer version;
     
     
     private Date date_debut;
     private Date date_fin;
     

     @Column(name = "activite_id", nullable = false, unique = true)
     @Id
     @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "activite_seq")
     @SequenceGenerator(name = "activite_seq", sequenceName = "activite_seq")
     @NotNull     
     public Integer getId() {
          return id;
     }

     public void setId(Integer id) {
          this.id = id;
     }

       @Version
     public Integer getVersion() {
          return version;
     }

     public void setVersion(Integer version) {
          this.version = version;
     }
     /**
      * @return the date_debut
      */
     public Date getDate_debut() {
          return date_debut;

then getters and setters...

Production.java :

package com.sopra.academy.seam.agora.entity;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import org.jboss.seam.annotations.Name;

@Entity
@Name("production")
@DiscriminatorValue("1") //le type pour une activité production est 1

public class Production extends Activite{

     private String libelle;
     private String descriptif;
     private String role;


     /**
      * @return the libelle
      */
     public String getLibelle() {
          return libelle;

(and other getter/setter)

The ProductionEdit.xhtml page (extract)

(this is the page generated by seam-gen, plus the fields date_debut and date_fin.)

<h:form id="production" styleClass="edit">

        <rich:panel>
            <f:facet name="header">#{productionHome.managed ? 'Edit' : 'Add'} Production</f:facet>


            <s:decorate id="libelleField" template="layout/edit.xhtml">
                <ui:define name="label">Libelle</ui:define>
                <h:inputTextarea id="libelle"
                               cols="80"
                               rows="3"
                              value="#{productionHome.instance.libelle}"/>
            </s:decorate>

            <s:decorate id="date_debutField" template="layout/edit.xhtml">
                <ui:define name="label">Date_debut</ui:define>
                <rich:calendar id="date_debut"
                          value="#{productionHome.instance.date_debut}" datePattern="MM/dd/yyyy" />
            </s:decorate>


            <s:decorate id="date_finField" template="layout/edit.xhtml">
                <ui:define name="label">Date_fin</ui:define>
                <rich:calendar id="date_fin"
                          value="#{productionHome.instance.date_fin}" datePattern="MM/dd/yyyy" />
            </s:decorate>

            <s:decorate id="roleField" template="layout/edit.xhtml">
                <ui:define name="label">Role</ui:define>
                <h:inputTextarea id="role"
                               cols="80"
                               rows="3"
                              value="#{productionHome.instance.role}"/>
            </s:decorate>

But, in fact, I wanted to implement JOINED inheritance.

So, I transformed the :

@Inheritance(
strategy=InheritanceType.SINGLE_TABLE)

into :

@Inheritance(
strategy=InheritanceType.JOINED)

Then, it ignores the discriminator (it seems normal to me, so I think one can remove it...)
Three tables are created, with an foreign key from each child to the parent table.

And the insertion orders look like these :

2009-03-10 11:57:32 CET LOG:  execute <unnamed>: insert into activite (date_debut, date_fin, version, activite_id) values ($1, $2, $3, $4)
2009-03-10 11:57:32 CET DETAIL:  parameters: $1 = '2009-03-11 00:00:00', $2 = '2009-03-25 00:00:00', $3 = NULL, $4 = '450'

2009-03-10 11:57:32 CET LOG:  execute <unnamed>: insert into Production (descriptif, libelle, role, activite_id) values ($1, $2, $3, $4)
2009-03-10 11:57:32 CET DETAIL:  parameters: $1 = 'e', $2 = 'e', $3 = 'eee', $4 = '450'

That is fine, too.

Now, I only have a problem with this :

<rich:calendar id="date_debut"
                          value="#{productionHome.instance.date_debut}" datePattern="MM/dd/yyyy" />

Because I do not know how to update the field 'date_debut' without the 'rich'. I tried with an h:inputTextarea but the updates are ignored...

If there is any problem here, of if you have comments, please let me know.

Flo