CRUD avec une association OneToMany sous Struts 2 / Hibernate 3

Bonjour

je suis en train d'implémenter un CRUD avec une assocation OneToMany sous Struts 2 / Hibernate 3.
j'ai deux entities Parent et Child:

@Entity
@Table(name="PARENT")
public class Parent {
private Long id;
private Set<Child> values = new HashSet<Child>();
..
@Entity
@Table(name="CHILD")
public class Child {
private Long id;
private String name;
..

Je peux facilement créer supprimer un Parent ou lire un Child Set (values) mais impossible de faire un update du Child Set.
la page jsp (voir plus bas) reinitialise le Set values, tous les enregistrements de ce Set sont supprimés après la maj de l'instance d'un Parent!
Pouvez-vous me dire ce qui cloche? Je vous serais éternellement reconnaissant car j'y perds mon latin ;-)

Le code:

@Entity
@Table(name="PARENT")
public class Parent {
private Long id;
private Set<Child> values = new HashSet<Child>();
@Id
@GeneratedValue
@Column(name="PARENT_ID")
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
@JoinTable(name = "PARENT_CHILD", joinColumns = { @JoinColumn(name = "PARENT_ID") }, inverseJoinColumns = { @JoinColumn(name = "CHILD_ID") })
public Set<Child> getValues() {
return values;
}
public void setValues(Set<Child> lst) {
values = lst;
}
}

@Entity
@Table(name="CHILD")
public class Child {
private Long id;
private String name;
@Id
@GeneratedValue
@Column(name="CHILD_ID")
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
@Column(name="NAME")
public String getName() {
return name;
}
public void setName(String val) {
name = val;
}
}

public interface ParentDAO {
public void saveOrUpdateParent(Parent cl);
public void saveParent(Parent cl);
public List<Parent> listParent();
public Parent listParentById(Long clId);
public void deleteParent(Long clId);
}

public class ParentDAOImpl implements ParentDAO {
@SessionTarget
Session session;
@TransactionTarget
Transaction transaction;

@Override
public void saveOrUpdateParent(Parent cl) {
try {
session.saveOrUpdate(cl);
} catch (Exception e) {
transaction.rollback();
e.printStackTrace();
}
}

@Override
public void saveParent(Parent cl) {
try {
session.save(cl);
} catch (Exception e) {
transaction.rollback();
e.printStackTrace();
}
}

@Override
public void deleteParent(Long clId) {
try {
Parent cl = (Parent) session.get(Parent.class, clId);
session.delete(cl);
} catch (Exception e) {
transaction.rollback();
e.printStackTrace();
}
}

@SuppressWarnings("unchecked")
@Override
public List<Parent> listParent() {
List<Parent> courses = null;
try {
courses = session.createQuery("from Parent").list();
} catch (Exception e) {
e.printStackTrace();
}
return courses;
}

@Override
public Parent listParentById(Long clId) {
Parent cl = null;
try {
cl = (Parent) session.get(Parent.class, clId);
} catch (Exception e) {
e.printStackTrace();
}
return cl;
}
}

public class ParentAction extends ActionSupport implements ModelDriven<Parent> {

private static final long serialVersionUID = -2662966220408285700L;
private Parent cl = new Parent();
private List<Parent> clList = new ArrayList<Parent>();
private ParentDAO clDAO = new ParentDAOImpl();

@Override
public Parent getModel() {
return cl;
}

public String saveOrUpdate()
{
clDAO.saveOrUpdateParent(cl);
return SUCCESS;
}

public String save()
{
clDAO.saveParent(cl);
return SUCCESS;
}

public String list()
{
clList = clDAO.listParent();
return SUCCESS;
}

public String delete()
{
HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST);
clDAO.deleteParent(Long.parseLong(request.getParameter("id")));
return SUCCESS;
}

public String edit()
{
HttpServletRequest request = (HttpServletRequest) ActionContext.getContext().get(ServletActionContext.HTTP_REQUEST);
cl = clDAO.listParentById(Long.parseLong(request.getParameter("id")));
return SUCCESS;
}

public Parent getParent() {
return cl;
}

public void setParent(Parent cl) {
this.cl = cl;
}

public List<Parent> getParentList() {
return clList;
}

public void setParentList(List<Parent> clList) {
this.clList = clList;
}
}

and finally the jsp page:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Parent Registration Page</title>
<s:head />
<style type="text/css">
@import url(style.css);
</style>
</head>
<body>
<s:form action="saveOrUpdateParent">
<s:push value="parent">
<s:hidden name="id" />
<s:push value="values">
<s:iterator id="p" value="values">
<s:textfield label="Nom" name="values(%{id}).name" value="%{name}"/>
</s:iterator>
</s:push>
<s:submit />
</s:push>
</s:form>

<s:if test="parentList.size() > 0">
<div class="content">
<table class="userTable" cellpadding="5px">
<tr class="even">
<th>Child(s)</th>
</tr>
<s:iterator value="parentList" status="userStatus">
<tr
class="<s:if test="#userStatus.odd == true ">odd</s:if><s:else>even</s:else>">
<td><s:property value="values.size()" /></td>
<s:iterator value="values">
<td><s:property value="name" /></td>
</s:iterator>
<td><s:url id="editURL" action="editParent">
<s:param name="id" value="%{id}"></s:param>
</s:url> <s:a href="%{editURL}">Edit</s:a></td>
<td><s:url id="deleteURL" action="deleteParent">
<s:param name="id" value="%{id}"></s:param>
</s:url> <s:a href="%{deleteURL}">Delete</s:a></td>
</tr>
</s:iterator>
</table>
</div>
</s:if>
</body>
</html>