[jboss-user] [EJB 3.0] - how to safe update

[serj_]

hello

I want to know what settings should have for safe updates using stateless beans (if it is possible), when have concurrency. I try to test using this code:

//this code is from Runnable objects (I have many objects of this type):

  | 			for(int i=0;i<UPDATE_NO;i++){
  | 				int amount = ran.nextInt(1000);
  | 				amountSum +=amount;
  | 				testSessionC.adjust2Balance(balance.getId(),amount);
  | 			}
  | 

//stateless bean:

  | @Stateless
  | @Remote(TestSessionC.class)
  | @Local(TestSessionC.class)
  | public class TestSessionCBean implements TestSessionC{
  | 
  | 	@PersistenceContext(unitName = "...")
  | 	EntityManager em;
  | 
  | 	public void adjust2Balance(long id, int amount) {
  | 		Balance b = em.find(Balance.class, id);
  | 		em.lock(b, LockModeType.WRITE);
  | 		float old = b.getAmount();
  | 		b.setAmount(old+amount);
  | 		em.merge(b);
  | 	}
  | 
  | }
  | 

my Balance entity use version control:

  | 	@Version
  | 	@Column(name = "OPTLOCK")
  | 	public int getVersion() {
  | 		return version;
  | 	}
  | 
  | 

thanks for any ideea

View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4066930#4066930

Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4066930