Re: critical sections in beans (transactions?)

[Laurel Neustadter]

Hi Bill:

Is myEntityBean.checkValue() checking the value of a persistent field? If
so, why can't that call be part of your transaction ... i.e.,

     // start transaction
     if (myEntityBean.checkValue())
     {
       myOtherEntityBean.update();
       myEntityBean.update();
       // end transaction
     }
     // end critical section


If you need a write lock on the value you are checking, you probably need to
use BMP so you can do a SELECT ... FOR UPDATE. You probably want an
isolation level of Serializable.

Is there a reason why making myEntityBean.checkValue()part of the
transaction is unworkable? Some more background on what you are trying to
accomplish with myEntityBean.checkValue()would be helpful ...

Laurel

-----Original Message-----
From: Bill Leonard [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, August 29, 2001 6:20 AM
To: [EMAIL PROTECTED]
Subject: critical sections in beans (transactions?)


I have the following SessionBean method and want to block other clients when
they try to call checkValue() if another client is already in the critical
section.  Further, I need to execute an update to the enity bean and another
entity bean in a transaction.

Can I do this using transactions and isolation levels in EJB?

MySessionBean
{
  mySessionBeanMethod()
  {
     // start crtical section
     if (myEntityBean.checkValue())
     {
       // start transaction
       myOtherEntityBean.update();
       myEntityBean.update();
       // end transaction
     }
     // end critical section
  }
}

Thanks,
Bill

===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".

===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST".  For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".