Issue with JPS and refreshing Entity bean's data.

[Kevin P Smith]

Hi guys
I was just wondering if someone could explain what seems like an obvious issue to me, but something I'm finding very hard to get around.
If I goto the page displaying the value for 'name' I get the expected result, however if the value is changed in the database and I move
away from the page and back again, I still get the
original value, not the updated value.
Whilst debugging my code, I can see that it goes into the .getUser(int userId) method in the Service again,
so I'd expect it to get the ;atest data from the database but it doesn't. I've tried _em.refresh(userDao) but get an error about the
Entity not being managed even if I add @ManagedBean("userDao") to the Entity bean,
and I've tried _em.clear() but still I get the original data.

Here is the test code....

Service:

package com.test.service;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.test.dao.UserDao;

@Service
public class UserProfileServiceImpl implements UserProfileService {

	private EntityManager _em;
	private UserDao userDao;

	@PersistenceContext
	public void setEntityManagerFactory(EntityManager entMgr) {
		this._em = entMgr;
	}

	@Transactional(readOnly = true)
	public UserDao getUser(int userId) {
		// neither of these worked as I'd hoped.
		// _em.refresh(userDao);
		// _em.clear();
		userDao = (UserDao) _em.find(UserDao.class,userId);
		return userDao;
	}
}

Entity

package com.test.dao;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;

@Entity
@Table(name = "users")
@Cache(usage = CacheConcurrencyStrategy.TRANSACTIONAL)
public class UserDao implements Serializable {

   	private static final long serialVersionUID = -7381920238852898257L;

	@Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    
    @Column(name = "firstname")
	private String firstname;

	public void setId(int id) {
		this.id = id;
	}
	public int getId() {
		return this.id;
	}
	
	public void setFirstname(String firstname) {
		this.firstname = firstname;
	}
	public String getFirstname() {
		return this.firstname;
	}
}

Controller

package com.test.controllers;

import java.io.Serializable;

import javax.annotation.ManagedBean;
import javax.inject.Inject;

import org.springframework.context.annotation.Scope;

import com.test.service.UserProfileService;

@ManagedBean("user")
@Scope("session")
public class UserProfileController implements Serializable {

	private static final long serialVersionUID = 5796722189527726467L;
	private UserProfileService userProfileService;
	private String name;
	
	@Inject
	public UserProfileController(final UserProfileService userProfileService) {
		this.userProfileService = userProfileService;
	}
	
	public void setName(String name) {
		this.name = name;
	}
	public String getName() {
		name = this.userProfileService.getUser(1).getFirstname();
		return name;
	}
}

Thanks in advance

[Kevin P Smith]

Added note:

I've seen that it does actually appear to be working, but there is a delay in the Entity bean picking up the new data! If I navigate away then straight back, I get the original data but if I wait for TWO MINUTES! then navigate away/back, it works! What's that all about, why is there this delay, surely this should be something that happens on access not on access (eventually).

[Vishwanath Krishnamurthi]

Hi,

You are caching the entity with @Cache. So I think you might have been given the cached value. That should explain why the value was stale.

HTH,
Vishwa

[Kevin P Smith]

Vishwanath Krishnamurthi wrote:Hi,

You are caching the entity with @Cache. So I think you might have been given the cached value. That should explain why the value was stale.

HTH,
Vishwa

D'OH!
That'll teach me. I really should spend a little more time reading what all the annotations are for!
Daft thing is I've used these annotations before but not the @Cache one, so it should have stood out to me.

Googled "@Cache (usage=CacheConcurrencyStrategy.TRANSACTIONAL)" first result that comes back:-

We also annotate the classes with the @Cache annotation to indicate that the values should be cached
@Entity
@Cache (usage=CacheConcurrencyStrategy.TRANSACTIONAL)
This defines that Customer and Contact should be cached. Any attempt to look up Customer or Contact by their primary key, will first attempt to read the entry from the cache. If it cannot be found it will load it up from the database.

Cheers for that