Hi All,
I am looking for some design guidelines for creating business object EJBs.
1. Should I have business logic in entity beans ?
2. Should they just implement the insert/update/delete into
the corresponding table ?
3. As per the business logic, If an update/insert/delete
operation on a table requires updating/inserting/deleting
on a different table as well - where this logic should be coded ?
4. Should session beans be used for implemnting this busiiness logic ?
5. Should there be one instance of session bean for each instance
of corresponding entity bean ?
6. Should session beans be used to wrap Entity beans ? If yes,
what should be the criteria for selecting the entity
beans that needs wrapping ?
7. Should I have one session bean for one UI screen ?
Any help on these design issues will be greatly appreciated !
-----------------------------------------------------
B. Arunmozhi
CARS Information Systems, http://www.carsinfo.com
Off.: 513-563-4542 Res.: 513-759-4469
> -----Original Message-----
> From: A mailing list for Enterprise JavaBeans development
> [mailto:[EMAIL PROTECTED]]On Behalf Of Ashwin Kumar
> Sent: Tuesday, July 27, 1999 2:43 PM
> To: [EMAIL PROTECTED]
> Subject: Re: probelm with deploying a bean
>
>
> hi ia a trying to run the container managed jdbc example that ships with
> with weblogic evaluation example.
> my bean is not getting deployed on the weblogic application gui
> console.further when i am trying to run the client
> is not able to find the account home context inside the
> getcontext function
> from root context.
> my weblogic.properties file looks like this
> weblogic.ejb.deploy=\
>
> d:/weblogic/examples/ejb/basic/containerManagedJDBC/AccountBeanDD.ser
> i am not sure whether it should be
>
> d:/weblogic/classses/ejb/basic/containerManagedJDBC/AccountBeanDD.ser
> these are the following in depoyment descriptor.txt
> (EntityDescriptor
> beanHomeName containerManagedJDBC.AccountHome
>
> The actual probelm occurs when ia m trying to ruin the client.it says
> containerManagedJDBC.AccountHome not found and teh bean never got
> deployed in weblogic console.
> if anyone of u know something about it pease reply to me.
> bye
> ashwin
>
> At 06:40 PM 7/26/99 -0700, you wrote:
> >Oops, I've been corrected that C is for Consistency.
> >
> >-Chris.
> >
> >"C is for Cookie", Cookie Monster.
> >
> >> -----Original Message-----
> >> From: Chris Raber
> >> Sent: Monday, July 26, 1999 4:21 PM
> >> To: 'A mailing list for Enterprise JavaBeans development'
> >> Subject: RE: EJB transactions and multiple containers
> >>
> >> Mark,
> >>
> >> I'll try to give a vendor' perspective on this.
> >>
> >> -----Original Message-----
> >> From: Mark Feblowitz [SMTP:[EMAIL PROTECTED]]
> >> Sent: Monday, July 19, 1999 2:49 PM
> >> To: [EMAIL PROTECTED]
> >> Subject: EJB transactions and multiple containers
> >>
> >> We would like to understand whether the EJB specification
> >> defines/supports/prohibits transactions that cross container
> >> boundaries, and, if so, how such transactions are
> coordinated. If a
> >> transaction can span multiple containers/servers, which
> >> container/server is considered to be the Transaction Coordinator?
> >>
> >> The one that starts the transaction.
> >>
> >> We would also like to know whether such transactions could be
> >> carried
> >> out among containers provided by multiple vendors, and
> what protocol
> >> they would use to coordinate such transactions.
> >>
> >> This will work if the vendors use a common underlying transaction
> >> protocol. In GemStone/J we chose to build our transaction servive using
> >> CORBA CosTransaction for this reason. Many other EJB servers are also
> >> using CosTransaction. Interoperability between these containers is very
> >> possible, but of course the devil is in the details. Vendors will be
> >> driven by market interest in this requirement.
> >>
> >> If not defined in the specification, are there vendors that are
> >> solving this problem? How are they doing this?
> >>
> >> Using CORBA as the basis is a good start. Interop at the EJB
> level needs
> >> to be proven, but is theoretically very doable.
> >>
> >> Can CORBA objects participate in transactions
> coordinated by an EJB
> >> Server? Can EJB components participate in transactions
> coordinated
> >> on
> >> the CORBA side?
> >>
> >> This is the case with GemStone/J, and likely the case with other EJB
> >> servers that are CosTransaction based.
> >>
> >> Which of the ACID transaction properties are being (can be)
> >> preserved/guaranteed for global transactions (within a
> container and
> >> across container boundaries), given that serializability of local
> >> transactions doesn't imply serializability of global
> transactions?
> >> We
> >> know that atomicity is easy to achieve (via the two-phase commit
> >> protocol) - what about the other properties?
> >>
> >> Atomicity - The global transaction provides atomicity at the
> distributed
> >> transaction level. Resources participating in the transaction are under
> >> contract to do so at the resource level (e.g. JDBC transactions).
> >>
> >> Concurrency - This is the responsibility of the underlying
> transactional
> >> resource (e.g. JDBC connection).
> >> Isolation - This is the responsibility of the underlying transactional
> >> resource (e.g. JDBC connection).
> >> Durability - This is the responsibility of the underlying transactional
> >> resource (e.g. JDBC connection).
> >>
> >> So the transaction manager in concert with the underlying resource
> >> managers together provide for ACID.
> >>
> >> -Chris.
> >>
> >> ----------------------------------------------------------------------
> >> Chris Raber, Director Professional Services, GemStone Systems Inc.
> >> 100 West Big Beaver, Suite 200, Troy, MI 48084
> >> phone: (248)-680-6691, fax: (248)-680-6689,
> >> email: [EMAIL PROTECTED]
> >> web: http://www.gemstone.com/
> >> ----------------------------------------------------------------------
> >>
> >>
> >> Mark
> >>
> >>
> >> _______________________________________________________________________
> >> Mark Feblowitz 40 Sylvan Road
> >> Senior Principal Member of Technical Staff Waltham, MA
> >> 02451-1128
> >> GTE Laboratories Incorporated [EMAIL PROTECTED]
> >> (617) 466-2947, fax (617)
> >> 466-2618
> >>
> >>
> >>
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