[seam-dev] Seam 2.2 migration to Seam 3

Thu Mar 13 12:22:29 EDT 2014

Hi,

We have done the (almost) same move for our many
Seamv2/JSFv1.2/RFv3.3/JPA-Hibenate-WebSphere v7.0 applications to
CDIv1/JSF2.0/Primefacesv4/JPA-Hibenate-/WebSpherev8.5.5 and we faced the
same questions you are asking

As you probably already know, most of what makes Seam 2 so great is now
part of CDI and JSF 2.0, but unfortunately not all.

For the missing parts, Seam 3 was not an option (code being merged to DS)
and we tried to "fill the gaps" with CODI (that is being merged into DS)
and the still-in-development-DetaSpike project but, after many so-called
"migration proof of concepts" we finally decided to just build our own
"CDIUtils" library with the missing parts, with code borrowed  from CODI,
DS and omnifaces.
DS is a great framework but it does not really fits with our needs (Do lots
of thing we don't need and do other thing in a way we don't like, as the
"Strong typed navigation model/paradigm)

Our applications are all composed of many module: 1 JPA jar, 1 EJB module,
a WAR (Contains no Java except Primefaces related artefacts) , a "UnitTest"
jar and eventually a batch jar. The EJB at high level contains "Page
Controllers (Mostly SFSB or POJOs)", "Managers (SLSB)", MDBs and Web
Service endpoints (SLSB).

Our CDIUtils lib is composed of 7 jars:
- base jar with CDI components to manage property files, JSF Messages +
AJAX-aware JSF 2.0 exception handler (thanks to omnifaces), Entity+Rollback
CDI comp producers, JSF v2.0 locale, a CDI PageContext (=JSF ViewContext
assignable to producer), super classes for Controlers, Managers,
WebServices and batches and a few other goodies..
- batch: with classes to bootstrap weld-se and CDI alternatives to
EntityManager and Rollback providers, and alternatives to non-se contexts
(Request, Conversation..)
- jpa: depends on hibernate with a dedicated DB2 Dialect
- security: depend on Apache Shiro:  Shiro-CDI integration that expose 2
interfaces to application : authentication adn registry management
- pdf: depends on the FOSS version of iText, Cloned from the Seam 2 PDF
facelets tags + a CDi component to render Facelets with PDF tags
programatically
- WebSphere: depends on WebSphere, with the Hibernate JTA provider and
second level cache implementation
- test: depends on junit and selenium with a CDIfied Junit4Runner and CDI
alternatives to EntityManager and Rollback providers, and non-j2se contexts
(Request, Conversation..)
It seems to be a lot of code, but in reality it is not. It just exposed the
missing artefacts that were in Seam 2, not in JSF 2.0 and CDI

In a few words, we don't have any more a pages.xml nor components files and
we do not depends on external CDI related libs :
- Transactions are managed by the EJB Container itself
- JPA/HIbernate session are managed by our EntityManager CDI producer + an
@AroundInvoke annotated method in our Ctrl+Manager+MDB+batch superclass
that attach the em at each EJB method call and so solve the (in-)famous
"Hibernate lazy instantiation exception" solved by Seam 2 in its time
- Seam 2 security is replaced by by Apache Shiro with a nice shiro.ini file
that is similar to pages.xml for this
- Seam 2 PDF is replaced by our own lib
- thanks to JSF 2.0, navigation is done directly with the name of the page
without teh need to pages.xml file
- CDI basic conversation management is enough for us, so we use it. We had
to replace Seam 2 outjection, it's just a different way on thinking on CDI..
- The EntityManager producer was a bit tricky to create because it must
work in SFLB, SFSB, MDB, J2SE... and due to CDI contexts, but it now work
great
- We use weld for junit/batch even if WAS comes with a modified version of
OWB because of some bugs in different interpretation of CDI
- Moving from RichFaces to Primefaces was not so difficult and -this is our
perception- easier to use

I know this does not exactly answer your question but I thought that it may
be intersting for you to share our experience how we are moving out from
Seam 2 and I'm concisous that our situation may be different from other
(Usage of EJB ..)

If you need more details, I will be happy to share them. On some days I'm
thinking about writing somewhere what we did to migrate and eventually
share our "CDIUtils" source code (ie create an open source project) lib but
I'm not sure that that code is "universal" enough for that

Cheers

Denis

2014-03-12 22:00 GMT-04:00 Jon Da Vault <jdavault at redhat.com>:

> Hello list members,
>
> Earlier today I posed a couple questions that did receive one response.
> The response has spawned a few more of my own questions and I have included
> the response in my conversation/further questions below. The original
> question is in red, and the response is also called-out and in red. The
> continuation question is in green. There are a couple new questions posed
> after the continued (green and red) question portion. Thanks for your help!
>
> 1) The customer makes extensive use of Seam 2 remoting for their banking
> security application. Is there an equivalent in CDI (Weld) that will allow
> them to continue using remoting? If not, what alternatives do we offer in
> it's place?
> Mailing List Response: You can take a look at Errai, or simply use JAX-RS.
> Q:  Seam 3 appears to have it's own remoting functionality available much
> like Seam 2. URL: http://seamframework.org/Seam3/RemotingModule
> As you'll note, there is a large disclaimer stating that active
> development for the project is halted and that the project is also
> deprecated. However, I feel that if the customer moves from Seam 2 remoting
> to Seam 3 remoting they will incur a smaller amount of work than if they
> were to consider adopting a new technology such as Errai or JAX-RS as
> you've suggested as best cases. While they are interested in adopting a
> better or more appropriate technology for their application, they still
> want to rapidly make the move to Seam 3/Solder/CDI/Weld in the meantime and
> I think this sets them up nicely for migrating the rest of the technologies
> over. What the customer is extremely interested in knowing is if these
> technologies now sitting as-is (3.1 Snapshot I believe) can be said to be
> categorically stable and functional currently for this sort of temporary
> use case with full knowledge they aren't supported moving forward? If so,
> are there any migration documents available? If no migration documents are
> available, do you have anywhere you can point me in order to get a head
> start on creating one myself for our client? Do you agree with this
> short-term-win approach?
>
> 2) The customer currently uses Seam-managed Hibernate Sessions: he guesses
> they are not supported in CDI and wishes to know what is the best way to go
> moving forward? For example, something that is more conforming to JPA2 was
> mentioned.
> Mailing List Response: Moving to a more standard JPA environment would be
> best
> Q: Here again, there seems to be a Seam 3 persistence module available as
> before and I wonder if the customer could utilize this in the short term
> while preparing for an adoption of a new persistence technology lsuch as,
> say, just Hibernate? The URL I'm referencing is:
> http://seamframework.org/Seam3/PersistenceModule
>
> 3) Given that components.xml is a large part of their implementation in
> Seam2, how can we break it up to conform with CDI/Weld/Seam3?
> Mailing List Response: All depends on what is in their components.xml,
> there's no simple answer here.
> Q: I agree with this response. I do, however, have a snapshot of the
> components.xml and I know that it needs to be broken up into a few
> different places. Does anyone have experience in doing this? Please reply
> and I will send you the components.xml document if you'd like to assist in
> helping me to map the pieces to the appropriate places. If there's
> sufficient documentation online, as always, please direct me to it.
>
>
> Lastly, if you're not tired of reading my questions yet there are a couple
> new ones below:
>
> *First new question:* "There used to be a class in Seam 2 called
> org.jboss.seam.faces.Redirect.   We use this a few times to force a
> redirect in different cases.
>
> for example:
>
> 1.      When user enters a valid URL but is not yet logged on;  view is
> captured and user returned to it after successful logon.
>
> 2.      When we detect that a user is no longer logged on;  we redirect to
> a "Logon expired page"
>
> So, the question is:   What do I replace this with?   I looked in Seam 3
> but it doesn't appear to have been implemented (at least not in the
> seam-faces jar)."
>
> *Second new question:* Regarding their current usage of Seam 2 "We use
> the class org.jboss.seam.async.Dispatcher to create long running threads in
> the container.   Can you tell me what I should use instead?"
>
> Again, if there are any documents or web sites that deal with these
> questions specifically regarding migration I would greatly appreciate
> having them sent to me.
>
> Thank You,
>
> Jon Da Vault
> Consultant
> 206.369.2304
>
>
> _______________________________________________
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> seam-dev at lists.jboss.org
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>
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