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From "V. Cekvenich" <baseb...@newsguy.com>
Subject Re: Enterprise Java Beans (EJB)
Date Thu, 15 Aug 2002 15:28:11 GMT
No....
Here is what:
Bean (formBean in Struts for example) delegate to DAO for CRUD 
(Insert,Read, Update,Delete to SQL DB) and persistence, done by DAO.
DAO is an interface.
The interface could be, inside of the DAO and not known to bean 
(formBean), implemented inside of the DAO a few different ways.
You could have a DAO implementation using EJB or Castor or Jakrta OJB, 
or RowSet (I use RowSet).
If you have an interface, such as DAO pattern, you could change the 
implementation and not affect the rest of your application.
So ... make your persistance/CRUD and interface.

This lets you change how it does CRUD. You should be able to switch from 
JDO to EJB or OJB to RowSet/ResulSet.

If you have to refactor the whole application to junk EJB or JDO... that 
would not be great. A simple interface would do ya.

v.


Ned Wolpert wrote:
> When you say 'replace EJB with JDO' you mean replacing EJB's entity
> beans with DAO, right? (As opposed to session and message beans)  (I've
> never used DAO, just TopLink and CastorJDO instead of Entity beans or as
> BMP entity beans)  
> 
> On Thu, 2002-08-15 at 08:11, V. Cekvenich wrote:
> 
>>Consider draping a DAO around your persistence.
>>This way you can replace EJB with JDO or RowSet, should you need to
>>Ex DAO interface:
>>http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/basicportal/src_05d/basicPortal/src/org/apache/commons/DAO/BasicDAO.java?rev=1.1.1.1&content-type=text/vnd.viewcvs-markup
>>
>>I found a RowSet implementation of DAO works better than EJB.
>>
>>v.
>>
>>Ned Wolpert wrote:
>>
>>>EJB provides a way to easily encapsulate business logic and reduce
>>>complexity by moving some difficult functionality/designs into
>>>deployment instead of development. Transaction requirements defined in
>>>the deployment of the EJB beans as opposed to part of the development of
>>>the EJB beans. (And they are easy to migrate/scale to many computers
>>>based on deployment configuration, again, making that task easier for
>>>developers since the programmer does not need to do anything special to
>>>achieve this.
>>>
>>>Session beans contain the business logic (Servlets call them)
>>>Entity beans persist the info to the database. (Session beans call them)
>>>Message beans respond to JMS queues/topics.
>>>
>>>In reality, EJB is simply another design pattern... one that was
>>>over-hyped by the vendors, but can provide flexibility needed in some
>>>cases.
>>>
>>>On Wed, 2002-08-14 at 22:34, Josh wrote:
>>>
>>>
>>>>Don't suppose anybody can send me a pointer as to what EJB and Jboss
>>>>actually achieve? All i managed to glean from their website were some pretty
>>>>3d variations on the usual "our product in the middle and some arrows"
>>>>diagrams.
>>>>
>>>>-Josh
>>>>
>>>>"Rimmer, real dumplings, proper dumplings when they're properly
>>>> cooked to perfection, proper dumplings, should not bounce."
>>>>
>>>>----- Original Message -----
>>>>From: "Nikola Milutinovic" <Nikola.Milutinovic@ev.co.yu>
>>>>To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
>>>>Sent: Thursday, August 15, 2002 3:31 PM
>>>>Subject: Re: Enterprise Java Beans (EJB)
>>>>
>>>>
>>>>
>>>>
>>>>>>Does Tomcat support EJB?.....
>>>>>
>>>>>No, it is not the task of Tomcat.
>>>>>
>>>>>
>>>>>
>>>>>>if not, is there a project to migrate tomcat to support EJB?... it
will
>>>>>
>>>>be
>>>>
>>>>
>>>>>>a very nice feature...
>>>>>
>>>>>Other servers, like JBoss, are EJB containers, Tomcat can
>>>>
>>>>connect/integrate with them. There is a version of JBoss that comes bundled
>>>>with Tomcat. Take a look at http://www.jboss.org/
>>>>
>>>>
>>>>>Nix.
>>>>>
>>>>
>>>>
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>>>>
>>
>>
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>>
>>



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