Actually, the most elegant solution is to simply use Java
synchronization to process requests in a serial manner if
do not care about clients clicking links in the browser
multiple times.
This would just mean using the "synchronized" keyword in the
business delegate instance methods that invoke operations on
the stateful session bean instance. That way, even if mutiple
threads access/invoke calls on the business delegate, they
will wait for a monitor entry and never invoke one operation
on the SFSB instance when another operation on the very same
instance is being executed.
For example:
public class MyBusinessDelegate {
private MyStatefulSess sfsb = null;
public MyBusinessDelegate {}// look up and create instance
// of SFSB here
public synchronized void invokeSomeOperation() {
sfsb.someOperation();
}
public synchronized void invokeAnotherOperation() {
sfsb.anotherOperation();
}
}
And the above class would be used by clients to communicate
with the SFSB instance. That way, you do not care if your
clients are Swing/Web based (both are multi-threaded).
The only thing you need to ensure is that the above class
is the only 'funnel' to your stateful EJB. That is, other
developers in your team do not inadvertently circumvent your
business delegate and create their own access path to your
EJBs.
-krish
Borland
________________________________
From: Mirchandani, Vishal
[mailto:[EMAIL PROTECTED]
Sent: Thursday, August 12, 2004 4:04 PM
To: [EMAIL PROTECTED]
Subject: Re: second thread call to stateful session bean
Hey Ashwini,
In case you are not able to trade up the server operation, you
can handle the same at the client browser itself or at the event
Handler, in case
you have one.
Method 1:
In your browser, have a transparent div. When the button is
clicked, activate the div(visibility:visible) with maximum zIndex. This
way the page gets locked . Or
also you can have a message on the div saying: "Please wait".
When you receive the response, hide the div again.
Method 2:
Also it can be done in your architecture layout. Say for
instance the web page(e.g. jsp) submits the request to a servelet which
in turn calls the other classes
or the EJB. In this servelet you set a flag for processing and
in case the flag is true. Ignore all user intercepts. After processing,
set the flag to true and the servlet
will start taking responses.
Method 3:
Try and handle the exception in the bean itself and kill the
transaction. But this is not an efficient method as the server should
never get a call in case a request is being
processed. So 1 and 2 should work out for you.
Warm Regards,
Vishal Mirchandani
------------------------------------------------------------------------
------------------------------------
"I'm having amnesia and deja-vu at the same time... I think I
have forgotten this before..."
-----Original Message-----
From: Kalra, Ashwani
[mailto:[EMAIL PROTECTED]
Sent: Thursday, August 12, 2004 7:16 PM
To: [EMAIL PROTECTED]
Subject: second thread call to stateful session bean
hi,
I have web page in which use clicks of one hyperlink ,
this operation is time consuming so user clicks immediately on some
other link and I get the above exception on Oracal9i AS 9.03. All the
requests goes through the stateful session bean. How to handle it
gracefully.
Thanks & Regds
Ashwani
Ext: 1582
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