hmm for webservices which are most of the time staeless I'd use @Singleton @Lock(READ), do you need any state?
Romain Manni-Bucau Twitter: @rmannibucau Blog: http://rmannibucau.wordpress.com/ LinkedIn: http://fr.linkedin.com/in/rmannibucau Github: https://github.com/rmannibucau 2014-09-04 10:30 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>: > @Alex and @Romain > > Thanks for your answers. I forgot to mention that we need (for most of the > cases) transactions. > > For some of the production environments we use WebSphere 8.5.5 which still > is JavaEE 6 so we need to use EJB to handle transactions. > > @Romain > > I agree with your thoughts, the requirements from case to case should > decide the inplementation. I just thought listing pros and cons was a good > way to sort of wrap our heads around what might be things to consider. We > expose services using JAX-WS and/or JAX-RS and we need transactions. > Considering that I understand that you rather would use @Stateful > @RequestScoped rather than @Stateless? > > @Alex > > I see your comment on the fact that multiple requests each will use its own > instance of a stateless EJB. i assume however that @PostConstruct will only > be called once when the container instantiate the EJB and put it in the > pool and not once per request. So if I need request/client specific state > setup in @PostConstruct I would need to use a @Stateless @RequestScoped EJB > instead. Was your comment about that? > > Thanks > On 4 Sep 2014 09:22, "Alex Soto" <[email protected]> wrote: > >> BTW in Java EE 7 with @Transactional then you can create a POJO with >> RequestScoped and Transactional so no EJB is required. >> >> Moreover keep in mind that an stateless bean is used during the whole >> request, two concurrent requests won't reuse the same stateless bean. >> Alex. >> >> >> 2014-09-04 9:17 GMT+02:00 Romain Manni-Bucau <[email protected]>: >> >> > Hi >> > >> > interesting analyzis and way of doing it :). Personally I think the >> > other way around actually: >> > >> > 1) what do I need? >> > [potential answer] storing my state during JSF request -> I add >> > @RequestScoped >> > >> > 2) oops, I need transactions >> > -> add @Stateful (or use a service to delegate depending the case and >> > code architecture) >> > >> > etc... >> > >> > >> > What you forgot in pro/cons is stateless are pooled so they can be a >> > bottleneck if not well configured >> > >> > >> > Generally I don't use stateless anymore, only @Singleton for EJBs and >> > @Stateful if really a CDI bean doesn't match my case - for JSF you >> > often needs it to store a state within a scope (request, session, view >> > typically) and flush it at the end of the action in a transaction. >> > >> > So to come back to your question: start with the minimum you need and >> > don't try to get a "always use XXX", it would just be broken as all >> > general rules ;). Passing from an EJB to a CDI bean is almost nothing >> > to do and the only relevant info is a benchmark on *your* app (I saw >> > cases where postconstruct can be considered as free and cases where >> > injections were costly, so it depends too much on the code you >> > evaluate to be general. >> > >> > Hope it helps even if adding some blur ;) >> > >> > >> > >> > >> > >> > Romain Manni-Bucau >> > Twitter: @rmannibucau >> > Blog: http://rmannibucau.wordpress.com/ >> > LinkedIn: http://fr.linkedin.com/in/rmannibucau >> > Github: https://github.com/rmannibucau >> > >> > >> > 2014-09-04 8:48 GMT+02:00 Lars-Fredrik Smedberg <[email protected]>: >> > > Hi >> > > >> > > Trying to sort out the pros and cons of using a @Stateless EJB vs a >> > > @Stateful @RequestScoped EJB, can someone help me with the following >> > claims >> > > and see if I missed out on something?? >> > > >> > > Possible pros of @Stateless EJB >> > > >> > > - Any expensive @PostConstruct methods will be run once when the EJB is >> > > instantiated and put in the pool and not per request >> > > - Control over concurrency/resources on the server by being able to >> > > configure the EJB pools >> > > - Reuse of EJBs will not create much garbage to be handled by the GC >> > > >> > > Possible cons of @Stateless EJB >> > > >> > > - Having to tune and follow up on the pool usage. This might be >> > troublesome >> > > depending on the organization and responsibilities >> > > - Depending on the tuning requests might need to wait for an instance >> to >> > be >> > > available in the pool >> > > - @PostConstruct can not initialize any request/user dependent state of >> > the >> > > EJB since it will be shared by others >> > > >> > > Possible pros of @Stateful @RequestScoped EJB >> > > >> > > - No configuration of EJB pools needed >> > > - No calls will have to wait for an available instance, as many >> instances >> > > as needed will be created >> > > - @PostConstruct can be used to initialize request/user dependent state >> > of >> > > the EJB, the EJB instance will not be reused >> > > >> > > Possible cons of @Stateful @RequestScoped EJB >> > > >> > > - An expensive @PostConstruct will affect performance since it will run >> > > once per request (client request) >> > > - Generates more garbage to be handled by the GC >> > > - No built in way to control the number of concurrent calls >> > > >> > > >> > > - Are there any other obvious pros and cons with the two ways above? >> > > - In the end will it all depend on the use-case and how many pros the >> > > use-case/scenario will make use of? >> > > - Letting CDI lifecycle create and destroy stateful EJBs per request >> > > compared to handling a pool of stateless EJBs, is there a big >> performance >> > > difference? >> > > >> > > >> > > Hoping for help to shed some light on this >> > > >> > > Regards >> > > Lars-Fredrik >> > > >> > > >> > > -- >> > > Med vänlig hälsning / Best regards >> > > >> > > Lars-Fredrik Smedberg >> > > >> > > STATEMENT OF CONFIDENTIALITY: >> > > The information contained in this electronic message and any >> > > attachments to this message are intended for the exclusive use of the >> > > address(es) and may contain confidential or privileged information. If >> > > you are not the intended recipient, please notify Lars-Fredrik Smedberg >> > > immediately at [email protected], and destroy all copies of this >> > > message and any attachments. >> > >> >> >> >> -- >> +----------------------------------------------------------+ >> Alex Soto Bueno - Computer Engineer >> www.lordofthejars.com >> +----------------------------------------------------------+ >>
