@ModelAttribute detached object binding from <form:form> tag has a problem with 3.1.1

[beku8]

After migrating to spring 3.1.0 from spring 3.0.5 hibernate save method is encountering problem with detached object - when trying to save new object with saveOrUpdate(Object obj) method where obj has no id.

Here are the code samples and unimportant parts are omitted
Domains:

@Entity
@Table(name = "task")
public class Task implements java.io.Serializable {

	private Long id;
	private Set<TaskComment> taskComments = new HashSet<TaskComment>(0);

	@OneToMany(fetch = FetchType.LAZY, mappedBy = "task", cascade = CascadeType.REMOVE)
	@OrderBy("date")
	public Set<TaskComment> getTaskComments() {
		return this.taskComments;
	}

}

and the object I'm really trying to save is task_comment:

@Entity
@Table(name = "task_comment")
public class TaskComment implements java.io.Serializable {

	private Long id;
	private Task task;
	private String content;
	public TaskComment() {
	}

	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "task_id")
	public Task getTask() {
		return this.task;
	}

}

Controller:

       @RequestMapping(value="/{id}", method=RequestMethod.GET)
	public String getDretail(@PathVariable("id") long id, Model model){
		model.addAttribute("task", taskDao.find(id));
		model.addAttribute("taskComment", new TaskComment());
		return "task-detail";
	}
	
	@RequestMapping(value="/{id}", method=RequestMethod.POST)
	public String postComment(@PathVariable("id") long id, @ModelAttribute("taskComment") TaskComment taskComment, Model model){
		Task task = taskDao.find(id);
		taskComment.setUsers(securityService.getCurrentUser());
		taskComment.setTask(task);
		taskComment.setDate(new Date());
	

		taskCommentDao.saveOrUpdate(taskComment);

		return "redirect:/dashboard/task/" + id;
	}

HibernateFilter extends which extends from OpenSessionInViewFilter:

public class HibernateFilter extends OpenSessionInViewFilter {

	@Override
	protected Session getSession(SessionFactory sessionFactory) throws DataAccessResourceFailureException {
	Session session = SessionFactoryUtils.getSession(sessionFactory, true);
	//set the FlushMode to auto in order to save objects.
	session.setFlushMode(FlushMode.AUTO);
	return session;
	}

	@Override
	protected void closeSession(Session session, SessionFactory sessionFactory) {
	try{
	   if (session != null && session.isOpen() && session.isConnected()) {
	try {
	    session.flush();
	}
	catch (HibernateException e) {
	throw new CleanupFailureDataAccessException("Failed to flush session before close: " + e.getMessage(), e);
	}
	catch(Exception e){
	}
	}
	}
	finally{
	super.closeSession(session, sessionFactory);
	}
	}
	}

jsp exerpt:

<form:form modelAttribute="taskComment" method="post" cssClass="formFrm" style="padding:0;">
     <form:textarea path="content" cssStyle="width:99%;"/>
    <input id="submit-btn" type="submit" value="Add comment" class="buttons" style="float:right;margin:0;">							
</form:form>

Problem: overriding all the previous comments. In other words, Task domain contains only one taskComment after post which was the last entered. However, when I tried unit testing it had no problem, so I think it's the problem with @ModelAttribute binding.

Work around:

public String postComment(@PathVariable("id") long id, @ModelAttribute("taskComment") TaskComment taskComment, Model model){

                TaskComment taskComment2 = new TaskComment();
                taskComment2.setContent(taskComment.getContent());
		Task task = taskDao.find(id);
		taskComment2.setUsers(securityService.getCurrentUser());
		taskComment2.setTask(task);
		taskComment2.setDate(new Date());

		taskCommentDao.saveOrUpdate(taskComment2);
		return "redirect:/dashboard/task/" + id;
	}

So I tried in multiple ways to get this working. I wrapped it in a transaction, played with the entity annotations... Only initializing new TaskComment then copying properties from bound taskComment then saving works fine.

I could do this to all my objects but would really painful and ugly refactoring. Any ideas? Please, help.

p.s I'm using hibernate 3.5.6-Final and spring security 3.1.0 and included pom file if it helps.

[Marten Deinum]

And the problem is, doesn't it save, do you get an exception what exactly?!

Also not sure why you have your own HibernateFilter, flushing after execution isn't something I would do. In general such a "solution" is only to solve improper transaction management.

[Rossen Stoyanchev]

Have you noticed what's actually different in the content of taskComment and taskComment2? I can't quite see what could could possibly cause it override all the other comments. Without knowing anything else about your controller, I would expect taskComment was created by calling its default constructor. Can you confirm if that's the case through a breakpoint or log statements?

[beku8]

Sorry for not posting back that I figured out the problem.

@PathVariable("id") long id

was the problem. The new feature in 3.1 got me confused. Task ID was bound to TaskComment ID,
Thanks for your replies