On 21 Sep 00, at 2:45, Davide Mora wrote:
> Hi,
>
> i read some former emails about client demarcated
> transactions, expecially mails between Dan OConnor
> and Stuart Barlow named "UserTransaction problems",
> but i still have some doubts about this topic.
>
> 1- Is not required by ejb spec. to give access to
> transactions from the client. I'm right?
Hi Davide,
It depends on what you mean by "client." The ejb spec references
the J2EE spec to indicate the containers in which UserTransaction
must be made available. If my memory serves me, it's basically
just the web and ejb containers, but not a client container, applet,
or standalone application. In other words, we are required to
provide UserTransaction for, e.g., a servlet or JSP component.
>
> 2- UserTransactions are not currently supported by
> jBoss, rigth?
>
> 3- If i use an ejb server that support transactions at
> client side, my ejbs/clients will be portable between
> application servers that support this feature?
You can write portable clients if you only use UserTransaction
where it is mandated by the J2EE spec. In any case, the behavior
of UserTransaction seems well-defined and your clients should be
portable between application servers that provide UserTransaction
wherever you use it (e.g. if several application servers provide
UserTransaction to a client container as an extension, your client
code should be portable between this subset of J2EE servers.
jBoss wouldn't provide this extension, if it were left for me to
decide, because I'm not a big fan of client demarcated
transactions.)
>
> 4- If and when client demarcated transactions will be
> available for jBoss?
>
> 5- Where i can find more details/example about the
> "facade pattern with a stateless session bean"
> approach suggested by Dan OConnor?
This is probably the most well-known design pattern for EJBs, and
you can find this almost anywhere you find a discussion of EJBs.
My recommendation would be to check out the ejb-interest
archives or some web sites first (quick, easy, and free). Here's
some URLs I found quickly (their listing here is not necessarily an
endorsement of the content, but a proof-by-example that there is
information to be had):
http://theserverside.com/patterns/thread.jsp?thread_id=625
http://www.c2.com/cgi/wiki?SessionBeanWrapsEntityBeans
If you really want to buy something, there's a Wrox press book
coming out in a week or two to which I contributed. :-)
Hope this helps,
Dan
>
> Thank you,
> Davide
>
> __________________________________________________
> Do You Yahoo!?
> Send instant messages & get email alerts with Yahoo! Messenger.
> http://im.yahoo.com/
>
>
> --
> --------------------------------------------------------------
> To subscribe: [EMAIL PROTECTED]
> To unsubscribe: [EMAIL PROTECTED]
> Problems?: [EMAIL PROTECTED]
>
--
--------------------------------------------------------------
To subscribe: [EMAIL PROTECTED]
To unsubscribe: [EMAIL PROTECTED]
Problems?: [EMAIL PROTECTED]
