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From Edgar Poce <edgarp...@gmail.com>
Subject Re: Implementing JSR-170 as EJB Application
Date Wed, 29 Jun 2005 23:48:30 GMT
hi Florian

Florian Ried wrote:
> I'm trying to implement a JSR-170 Content Repository as an EJB 
> Application. This is a similar approach as described in JackRabbit 
> Deployment Model 3 (Repository Server with RMI). 
IMO it's not a similar approach.
If I understand you correctly you want to *implement* a jcr compliant 
repository. The JCR-RMI contribution is not a full implementation, it 
consists of two parts, a server that wraps an already implemented jcr 
repository (e.g. Jackrabbit), and a client that lets you access the 
remote server transparently.

> All methods in the (Remote-) interface RepositoryImpl have to throw 
> RemoteExceptions (see J2EE Spec) but the interface javax.jcr.Repository 
> doesn't define them. 
As you noted while compiling the remote interfaces of your EJBs, remote 
calls throw RemoteExceptions. jcr-rmi tackles this problem with a design 
that makes intensive use of the adapter pattern. It hides the 
RemoteExceptions and it makes the remote objects available locally 
through the jcr API. see 

 > Are there any solutions for this problem?
If you want to implement a jcr compliant repository from scratch it will 
be hard work and you'll find many more problems in the path. I guess you 
should ask the Day team, they already walked that path and did a great job.
If all you want is to access a remote jcr repository you might want to 
try jcr-rmi.

> Recompling the javax.jcr.* Interfaces?
it doesn't seem a good idea. What's the point of making a jcr compliant 
impl that's not jcr compliant? ;)

> Why is the scenario of building a JCR-Server on top of a EJB Container 
> not considered by the specification? Is the approach of building a JCR 
> by using an EJB Container the right way?
IMHO it's not.

> Is it perhaps possible to use jackrabbit within an EJB-Container (with 
> custom DB-Mapping)?
yes, you can use it in an ejb container. No matter the container I guess 
it shouldn't be so different to the example in the site. Just find out 
how to declare a jndi resource in your container and you'll be able to 
access the jcr repo either from your ejbs or from your jsp/servlets.

The db topic was discussed quite a few times in the list, you'll find 
many threads in the archive 
(http://dir.gmane.org/gmane.comp.apache.jackrabbit.devel). You can also 
take a look to the wiki 
(http://wiki.apache.org/jackrabbit/PersistenceManagerFAQ), it has some 
info about how the persistent storage is handled in jackrabbit and which 
are the current options.

kind regards,
> Thanks for your answers.
> -Flo

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