Questions on JBoss/Seam enterprise app architecture.

[cjalmeida]

(since this post has concerns on both EJB3 and SEAM, it has been cross-posted)

Our company is planning to replace a large portion of it's ERP system (currently is mainframe COBOL/ISAM indexed flat files based - doubt most younglings know what this is :). As you might guess, system is pretty unmaintainable and we if we don't change this situation, will get behind our competitors.

After a few months looking for technologies that will fit our needs and hopefully won't die in the next month, J2EE (specially with the EJB3 simplification) seems to be winning. The much I've been playing Seam made me think of it as a good candidate for the controller layer.

So, are the questions:

A) I want to have multiple applications interacting with the same Entity Beans (an ?Order? bean should be accessible from the ?Manufacturing? app and the ?Sales Mgmt?, a ?User? bean should be accessible everywhere). What's the best approach so I don't have to deploy the same .ejb3 containing User over and over?

(Why not using a single big application? I don't want to redeploy my entire application when doing and testing minor changes. One big massive .ear? Nah... The linux-kernel created modules for a good reason).

B) Will Seam access (and resolve for JSF) Entity Beans when they are defined outside the application but within the same JVM?

C) Since 70% of the application is mostly a ?web database front-end with few tweaks? (the rest is workflows and infra-structure), is there a JSF (or Facelets) ?autoform? widget that nicely displays a bean and CRUD related components needing very little information from the developer? (Hum... why am I thinking of Rails?)

I know this is not the best forum for the last question, but, if anyone knows...

Anyways, Seam looks very promising and the conversation context is a great idea!

C. J.

[gavin.king]

"cjalmeida" wrote:
A) I want to have multiple applications interacting with the same Entity Beans (an ?Order? bean should be accessible from the ?Manufacturing? app and the ?Sales Mgmt?, a ?User? bean should be accessible everywhere). What's the best approach so I don't have to deploy the same .ejb3 containing User over and over?

By "multiple applications" you mean multiple EARs? You would need to deploy the same entities in each EAR.

"cjalmeida" wrote:
B) Will Seam access (and resolve for JSF) Entity Beans when they are defined outside the application but within the same JVM?

No.

"cjalmeida" wrote:
C) Since 70% of the application is mostly a ?web database front-end with few tweaks? (the rest is workflows and infra-structure), is there a JSF (or Facelets) ?autoform? widget that nicely displays a bean and CRUD related components needing very little information from the developer? (Hum... why am I thinking of Rails?)

We have started prototyping some databound controls, but for the moment, the best approach is the reveng tool.

[cjalmeida]

Thanks for the reply Gavin.


I guess the answer for both A and B will be duplicating my entity beans. Hopefully, I can set up ant to build one ejb3 and copy it into the multiples ears.

But won't it confuse the deployer or the classloader? Is there a problem to deploy "beans.ejb3" multiple times inside different EARs?

As for the dababound controls it would be a very nice feature.

C. J.

[gavin.king]

You will need to use scoped classloading. In all our examples, we have a jboss-app.xml for that reason.

[cjalmeida]

Very nice. I'll study the examples.

Thx again.