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Struts & Hibernate
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| | | Exception Handling in J2EE project | Exception Handling in J2EE project 2003-12-08 - By Kancharlapalli,Sridhar
Back
Hi,
Designing custom exceptions are a sort of must in a framework so that we
throw/catch exceptions specific to the business process so that the client and
other business components are aware of business violations and exceptions.
Custom checked exceptions would contribute to the most of the exceptions we
define in our framework. Creating wrappers over existing exceptions wouldn't
serve the purpose in most of the cases except to complicate the process.
The main design consideration would be where to handle a specific exception, as
exception's consume memory and may affect the overall performance of the system
it is always good to spend enough time on designing exception handling.
For example:
Suppose we take the case of a Entity Bean:
Since the entity bean's are bundled with data logic, custom exceptions such as
FieldRequiredException can be raised from the bean. And also SQL exceptions
which indicate Duplicate records or any other such constraints can be rethrown
as a business exception from Entity Beans (with custom messages).
With the case of a Session Bean:
Most of the business exceptions are thrown from Session Bean as Business Logic
is bundled in them. Security Exceptions are easier to describe, if the session
bean is used as a Facade then it is a good idea to bundle security logic in
them.
With the case of Business Delegate:
This can be a place where non-business specific exceptions or unchecked
exceptions can be caught and re-thrown with custom messages. Since these
exceptions do not carry any importance to the business process (but might
affect a process indirectly), so handling them at the session or entity level
would just be inappropriate, but from the client point of view these exceptions
are to be notified with readable messages.
Hope above description helps you, it is just my observations and experience I
am sharing with you and any suggestions are welcomed.
-Sridhar Kancharlapalli.
Hi All,
What is the best Hierarcy (framework) for handling exceptions in a
J2EE project.
I am thinking of some roughly the following Hierarcy consisting
broadly of three categories :
+ MyApplicationException extends Exception ( For handling bussiness
exceptions.)
- InsufficientBalanceException
- InvalidPasswordException
- etc.
+ MySystemException extends RuntimeException (Non bussiness
exception, exception due to System problems)
+ MyEJBException extends EJBException (Not too sure if this is
required)
My question is :
1. Is this approach correct ?
2. My application flow consists of
ActionClass calls BussinessDelegate calls SessionBean calls
DAO and
ActionClass calls BussinessDelegate calls SessionBean calls
EntityBeans
How should the exception for take place. Should it be something
like this:
DAO throws some ApplicationException ...
caught by SessionBean thrown as some EJBException ......
caught by BussinessDelegate and do some handling
Regards,
Prasenjit.
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