Concurrency attribute on Component Properties/Instances tab

I have a stateless session bean where an instance is not thread-safe.

By definition session beans (Stateful/Stateless) need not be thread
safe. It is supposed to be guaranteed that the container ensures that at
a given point of time only one method call will be executing for an
instance. (i.e.,one thread per instance).
Given this background what meaning does the Concurrency attribute have
for a Stateless session bean.
I have a stateless session bean where the instance itself is not thread
safe. However I can have multiple instances calling the same method.
(Basically it is not thread safe).

If I have multiple requests for the same method call at  a given point
of time, will the container create multiple instances to service the
requests or will they be serialized.

Given above what should my concurreny attribure be set for the above
Stateless session bean

Thanks in Advance,
-Ganga



0
Ganga
8/16/2001 3:28:34 PM
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Ganga:

Answers inline...

--
Jonathan Baker
eBusiness Division
Sybase, Inc.


"Ganga Yerramsetti" <ganga_yerramsetti@ssga.com> wrote in message
news:3B7BE6A2.3787723D@ssga.com...
> I have a stateless session bean where an instance is not thread-safe.
>
> By definition session beans (Stateful/Stateless) need not be thread
> safe. It is supposed to be guaranteed that the container ensures that at
> a given point of time only one method call will be executing for an
> instance. (i.e.,one thread per instance).
> Given this background what meaning does the Concurrency attribute have
> for a Stateless session bean.

Concurrency means that multiple threads can run against the bean
simultaneously.  Since our default configuration is to put a separate
instance on each thread, this should normally be left on.  (The separate
instance will protect you from 'thread safe' code... UNLESS you are using
static variables).

> I have a stateless session bean where the instance itself is not thread
> safe. However I can have multiple instances calling the same method.
> (Basically it is not thread safe).

Sure you can.  We will assign a separate instance of the session bean to
each thread.

>
> If I have multiple requests for the same method call at  a given point
> of time, will the container create multiple instances to service the
> requests or will they be serialized.

Multiple instances.  If you want them to be serialized, let us know and
we'll tell you how to do that.

>
> Given above what should my concurreny attribure be set for the above
> Stateless session bean

See answer above.



>
> Thanks in Advance,
> -Ganga
>
>
>


0
Jonathan
8/16/2001 10:05:38 PM
Reply:

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