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Re: [wtp-dev] Mixing spec levels in EAR. Opinions?
- From: "Max Rydahl Andersen" <max.andersen@xxxxxxxxxx>
- Date: Mon, 14 Jul 2008 21:46:16 +0200
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I've been on vacation so not sure how much have been said and done in this thread yet.
I just want to clearly state that my belief is that an IDE like Eclipse should not
*prevent* users from doing things outside a spec or usecases if it can be avoided.
It should merely provide a *warning* if relevant (or error if the users decide that he wants "strict" mode)
Anything else is bound to be a straight jacket that prevents usage and adoption.
So in short, J2EE 1.4 apps should be allowed to include EJB3 parts - its a common supported case
by e.g. JBoss. And the spec does not say your are not allowed to do it, it is just not required by spec -
not the same thing as it not being illegal.
> Hi Kaloyan,
> Thank you for raising this issue. I agree we are inconsistent in parts,
> and although we don't necessarily need to resolve all of the issues
> immediately we should at least have a common definition of what is
> 'correct' and may eventually be supported by WTP.
> Among the IBM committers we generally agree with #2, but have made an
> interesting distinction: the schema used by a DD is only a bottom boundary
> on the spec level of the EAR or module. As an example, a '1.4' EAR that
> contains an EJB 3.0 module is really just an EE 5 EAR (or EE 6.0 or ...)
> with an older DD. Likewise, EJB 3.0 annotations within an EJB module is an
> indication that the EJB is at least EE 5/EJB 3.0, even if the DD still
> points to the EJB 2.0 schema.
> If DD schemas and spec API usage are just a bottom boundary, it means that
> there is nothing within the contents of an EAR or module that can
> precisely determine its level. So how do we tell if it is valid for a user
> to add an EJB 3.0 module to what currently looks like a 1.4 EAR? Was it
> really an EE 5 EAR all along, do they want to uplevel the EAR, or is the
> user simply making a mistake?
> The solution we came to is using facets. Facet versions allow the user to
> tell us which spec level they expect an EAR/module to be at, and gives us
> something to tool for and validate against. The versions are set on
> project creation or on import based on what we initially find in the
> modules. From there, the facet version of an EAR determines the maximum
> spec level of modules that can be added or which servers it can be run on,
> and validation can show errors for invalid modules or if the DD points to
> a schema above the level of the facet.
> If you agree with the original distinction (that true EAR 1.4s can't hold
> EJB 3 modules, but the schema used by the DD is only a bottom boundary on
> the spec level), then I think you'll eventually come to the same
> conclusion we have. Please feel free to let me know what you think and
> others can chime in, or we can discuss on one of the WTP calls.
> Tim deBoer
> "Raev, Kaloyan" <kaloyan.raev@xxxxxxx>
> "General discussion of project-wide or architectural issues."
> 06/26/2008 09:04 AM
> [wtp-dev] Mixing spec levels in EAR. Opinions?
> I want to bring up again an issue that was discussed some time ago in
> Bugzilla. It is about mixing of spec levels of EAR and included modules.
> There are two bugs related:
> Everybody agree that EAR with spec level X could include modules with
> spec level X or lower. Example: EAR 5 can include EJB 2.1.
> But there is no consensus of opinion on EAR with spec level X to include
> modules with spec level higher than X. Example: EAR 1.4 to include EJB
> 3.0. There are two contrary opinions:
> 1. EAR 1.4 can include EJB 3.0
> 2. EAR 1.4 cannot include EJB 3.0.
> The supporters of opinion 1 says that it is not forbidden by the Java EE
> The supporters of opinion 2 says that it is (at least indirectly)
> forbidden by the spec. This is because the contract of the Java EE spec
> says that a deployment module compliant with spec level X must always be
> able to deploy on an application server compliant with spec level X. Now
> let's look again at our example of EAR 1.4 including EJB 3.0. EAR 1.4 is
> a J2EE 1.4 deployment module and it is guaranteed by the spec that it
> will deploy on all J2EE 1.4 compliant servers. But if we try to deploy
> it on an J2EE 1.4 compliant app server, that is not at the same time
> Java EE 5 compliant, then our deployment will fail, because of the
> included EJB 3.0 module (which is Java EE 5 spec level).
> At the moment there is an inconsistency in several dialogs in WTP
> regarding this issue. For example the Java EE Module Dependencies
> property page of an EAR 1.4 project filters Java EE 5 modules for
> selection, while at the same time the project creation wizard allows a
> EJB 3.0 project to be added to an existing EAR 1.4 project.
> I suggest that we discuss this problem and hope we will have an
> agreement for WTP 3.0.1. I invite all application server vendors
> represented in this mailing list to express their support for either
> opinion 1 or opinion 2.
> Kaloyan Raev
> Eclipse WTP Committer
> Senior Developer
> NW C JS TOOLS JEE (BG)
> SAP Labs Bulgaria
> T +359/2/9157-416
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