EJB's are not quite 100% portable today, given variance in spec complliance
across servers... But it si the 80/20 rule, and much better than no spec at
all.
My personal experience in porting other EJB server beans to GemStone/J has
been quite positive.
-Chris.
> -----Original Message-----
> From: Assaf Arkin [SMTP:[EMAIL PROTECTED]]
> Sent: Friday, December 10, 1999 8:42 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Are we mad?
>
> > Also, are EJBs really "Write Once, Run Anywhere"? I have heard stories
> > that it doesn't do that... The two articles from the techmetrix website
> > does not seem to think it does.
>
> Nope. But the fact that you can learn EJB once and program for any
> server, and move code between server with reasonable modifications, is a
> boon. I think EJB portability is more about developer and expertise than
> about code.
>
> If you compare EJB to the current state of application servers, where
> your code is 100% non portable and you need to relearn the API when you
> change products (or try to integrate them), then you'll see the benefit
> of EJB.
>
>
> > The fact that EJB restricts loading native libraries (I interpret it as
> > prohibit JNI calls) makes reuse of existing components impossible if the
> > implementation of the component is not implemented in Java (which IMHO,
> > is the majority of the case). The spec did not mention of any other way
> > to allow such software reuse. Now we could wrap these components with a
> > normal Java class (not an EJB), and have EJB import these classes, but
> > inherently, this is really no different from issuing JNI calls within
> > EJB itself. Or am I interpreting this all wrong?
>
> It does not prohibit you, e.g. from using a library that might access
> JNI or spawn it's own thread. JDBC, JMS and even JNDI are prime examples
> of that. But they they have been properly designed to provide their own
> level of reliability, security, monitoring, etc so you can trust them to
> work well in a demanding environment.
>
> EJB relieves you of the need to care about reliability, security and
> scalability when you write beans, all these is simplified and
> abstracted, but in return you have to promise not to violate the design
> that gives you all that.
>
>
> > Also, if EJB prohibit synchronizing threads, how would it adress the
> > typical producer/consumer problem which is quite a common scenario in
> > server requirements/designs?
>
> There is no producer/consumer in the EJB world, this sort of
> functionality either leaves on the client or inside the resources that
> the EJB bean accesses. Typically if your business logic is about being
> produced/consumed you will be looking at JMS.
>
> I think what we need are good real world scenarios so people can see how
> different design patterns are being used and reflect that on their
> projects.
>
> arkin
>
> > Lastly, I'm curious on how the container classes is designed,
> > generically enough to meet everyone's need and flexible enough for
> > people to customize??? And if the container classes do allow
> > customization, how can it guarantee the EJB components can WORA? Where
> > would I find the spec/guidelines for that?
> >
> > Thank you very much for your responses...
> >
> > Manomohan Kalathil wrote:
> > >
> > > Visit www.techmetrix.com for a study of a few of these appservers
> > >
> > > Mano
> > >
> > > |Subject: Application Server - Feedback
> > > |
> > > |
> > > |Hello,
> > > | Following is a list of app servers that I am currently
> evaluating.
> > > |
> > > | WebLogic
> > > | Secant
> > > | Novera ( I would like to but no download is available :( )
> > > | WebSphere
> > > | NetDynamics ( but SUN recently announce their new product
> > > |availability
> > > | in early next year - alliance with Netscape - On hold
> )
> > > | Oracle
> > > |
> > > |
> > > |
> > > |
> > > | If anybody has experince on these products would you please send
> me
> > > | their feedbacks on these products.
> > > |
> > > | I am looking at the following features.
> > > |
> > > | 1. Scalability
> > > | 2. Fault tolerence
> > > | 3. Maintanability
> > > | 4. Transaction Mgmt - Anybody supports nested and distributed
> > > |transactions
> > > | 5. Application Partioning
> > > | 6. EJB1.1 support
> > > | 7. IDE integration
> > > | 8. Integration with bean providers like Theory center - not
> > > |anymore ( WebLogic
> > > | got them, I think )
> > > |
> > > | 9. Easy to use and minimal configuration
> > > | 10. Mem/Space reqmts.
> > > | 11. Database Independence
> > > |
> > > | Any help is really appreciated - Especially if anybody has
> > > |done a thorough study on any
> > > |of these app servers and would like to share your experince will
> > > |be a great help.
> > > |
> > > |
> > > | -Thx
> > > | -Reji
> > > |
> >
> > --
> > Yiwen Jiang
> > CRYPTOCard
> > [EMAIL PROTECTED]
> > Tel: (613) 599-2441 x245
> > Fax: (613) 599-2442
> >
> >
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> --
> ____________________________________________________________
> Assaf Arkin [EMAIL PROTECTED]
> CTO http://www.exoffice.com
> Exoffice, The ExoLab Company tel: (650) 259-9796 << File: Card
> for Assaf Arkin >>
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