You are viewing a plain text version of this content. The canonical link for it is here.
Posted to user@struts.apache.org by Navjot Singh <na...@net4india.net> on 2003/04/03 12:05:13 UTC
Where to catch/throw Exceptions in Struts Tiered Architecture
Hi,
Take a simple case.
Action
Y
UserAction -> User -> Database
|
V
user.jsp
Say, Database throws exception. What is best way to handle exception?
1. Catch in User class and return NULL / some ErrorObject to UserAction and
let UserAction decide how to handle it?
2. Let User class __pass on__ the Exception from Database to UserAction.
2a. As execute() is already throwing Exception so it will handle ALL so Set
<global-exception> handler that can send the user to some nice page?
2b. Catch Exception in UserAction and then do some thing ...
Which one do you guys follow in not-so-large scale web applications?
would appreciate any comments.
-navjot singh
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
Re: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Navjot Singh <na...@net4india.net>.
thanks gareth, i got the point.
thanks to Ted (Tip 15) and Andrew as well.
-navjot
----- Original Message -----
From: "Gareth Andrew" <ga...@ntlworld.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 4:09 PM
Subject: Re: Where to catch/throw Exceptions in Struts Tiered Architecture
| IMO, catch the database exception in user, then throw a new (wrapped)
| exception, catch it in UserAction and throw a new exception, and use
| struts decalritive exception handling features to handle it. This
| avoids undue coupling between UserAction, User and Database.
|
| Gareth.
|
| Navjot Singh wrote:
|
| >Hi,
| >
| >Take a simple case.
| >
| > Action
| > Y
| >UserAction -> User -> Database
| > |
| > V
| > user.jsp
| >
| >Say, Database throws exception. What is best way to handle exception?
| >
| >1. Catch in User class and return NULL / some ErrorObject to UserAction
and
| >let UserAction decide how to handle it?
| >
| >2. Let User class __pass on__ the Exception from Database to UserAction.
| >
| >2a. As execute() is already throwing Exception so it will handle ALL so
Set
| ><global-exception> handler that can send the user to some nice page?
| >2b. Catch Exception in UserAction and then do some thing ...
| >
| >Which one do you guys follow in not-so-large scale web applications?
| >
| >would appreciate any comments.
| >-navjot singh
| >
| >
| >
| >
| >---------------------------------------------------------------------
| >To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| >For additional commands, e-mail: struts-user-help@jakarta.apache.org
| >
| >
| >
| >
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
Re: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Gareth Andrew <ga...@ntlworld.com>.
IMO, catch the database exception in user, then throw a new (wrapped)
exception, catch it in UserAction and throw a new exception, and use
struts decalritive exception handling features to handle it. This
avoids undue coupling between UserAction, User and Database.
Gareth.
Navjot Singh wrote:
>Hi,
>
>Take a simple case.
>
> Action
> Y
>UserAction -> User -> Database
> |
> V
> user.jsp
>
>Say, Database throws exception. What is best way to handle exception?
>
>1. Catch in User class and return NULL / some ErrorObject to UserAction and
>let UserAction decide how to handle it?
>
>2. Let User class __pass on__ the Exception from Database to UserAction.
>
>2a. As execute() is already throwing Exception so it will handle ALL so Set
><global-exception> handler that can send the user to some nice page?
>2b. Catch Exception in UserAction and then do some thing ...
>
>Which one do you guys follow in not-so-large scale web applications?
>
>would appreciate any comments.
>-navjot singh
>
>
>
>
>---------------------------------------------------------------------
>To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
>For additional commands, e-mail: struts-user-help@jakarta.apache.org
>
>
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
Re: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Navjot Singh <na...@net4india.net>.
thanks a ton.
now, i need to spend some hours doing some arrangements in my code but
anyway that's for my good ;-)
-navjot singh
----- Original Message -----
From: "Andrew Hill" <an...@gridnode.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 5:02 PM
Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
| Generally, returning null when it should be an error is considered bad
| practice. (If null is a valid return value of course thats a different
| matter).
| In this case you should throw an exception and catch it in the calling
class
| and branch or throw again appropriately.
| You dont want your calling class to have to know about low level details
| like specific sql exceptions though, so instead of just letting the sql
| exception propogate upwards, you would catch it and throw a different more
| abstract exception (probably one you create yourself) up to the caller -
the
| caller shouldnt have to know the details about your persistence
mechanism -
| it just needs to know it failed - and sometimes needs to know if the
failure
| is fatal and any other pertinent info.
| The nested excpetion classes should also be able to keep a reference to
the
| exception they wrap so the stacktrace show all the exceptions in the
chain -
| useful when debugging.
|
| btw: If I recall rightly Ted Husted explains this 10 times better in one
| tenth the words in his book (struts in action)
|
| Have a look at these articles:
|
http://developer.java.sun.com/developer/technicalArticles/Programming/except
| ions/
| http://www-106.ibm.com/developerworks/java/library/j-ejb01283.html
| http://www.javaworld.com/javatips/jw-javatip91_p.html
|
| There was another very good one too - but it doesnt seem to be in my
| favourites list and I cant seem to find it now.
|
|
| -----Original Message-----
| From: Navjot Singh [mailto:navjot.s@net4india.net]
| Sent: Thursday, 3 April 2003 18:53
| To: Struts Users Mailing List; andrew.david.hill@gridnode.com
| Subject: Re: Where to catch/throw Exceptions in Struts Tiered
| Architecture
|
|
| hi andrew,
|
| but surely these long stacktraces are not meant for users ;-)
|
| what i have got from your statement is something like this
|
| SQLException
| |__DatabaseException
| |____ApplicationException
|
| finally, this ApplicationException is what is being thrown into execute()
| call.
|
| May i am novice, but I still need to be convinced about throwing so many
| exceptions in chain
|
| Can't the stuff be handled in a simple way --
| SAY
| a. when you get SQLException, catch and return NULL
| b. Calling Class __ifs__ for NULL instead of __catching__ and transfer the
| control accordingly.
|
| Is there something i am ignoring?
|
| regards
| Navjot Singh
|
| ----- Original Message -----
| From: "Andrew Hill" <an...@gridnode.com>
| To: "Struts Users Mailing List" <st...@jakarta.apache.org>
| Sent: Thursday, April 03, 2003 3:49 PM
| Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
|
|
| | I use nested exceptions, and virtually all my methods (and thus layers)
| | catch and wrap and throw...
| | Makes for some impressively long stacktraces - and is marvellous for
| | debugging! :-)
| |
| |
| | -----Original Message-----
| | From: Navjot Singh [mailto:navjot.s@net4india.net]
| | Sent: Thursday, 3 April 2003 18:05
| | To: Struts Users List
| | Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
| |
| |
| | Hi,
| |
| | Take a simple case.
| |
| | Action
| | Y
| | UserAction -> User -> Database
| | |
| | V
| | user.jsp
| |
| | Say, Database throws exception. What is best way to handle exception?
| |
| | 1. Catch in User class and return NULL / some ErrorObject to UserAction
| and
| | let UserAction decide how to handle it?
| |
| | 2. Let User class __pass on__ the Exception from Database to UserAction.
| |
| | 2a. As execute() is already throwing Exception so it will handle ALL so
| Set
| | <global-exception> handler that can send the user to some nice page?
| | 2b. Catch Exception in UserAction and then do some thing ...
| |
| | Which one do you guys follow in not-so-large scale web applications?
| |
| | would appreciate any comments.
| | -navjot singh
| |
| |
| |
| |
| | ---------------------------------------------------------------------
| | To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| | For additional commands, e-mail: struts-user-help@jakarta.apache.org
| |
| |
| | ---------------------------------------------------------------------
| | To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| | For additional commands, e-mail: struts-user-help@jakarta.apache.org
| |
| |
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
Re: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Navjot Singh <na...@net4india.net>.
hi andrew and list,
I have another small Q on nested exception.
Consoder a nomal web scenario, where a request comes to Action, delegated to
Business logic class, that class queries database and follows the path back.
CustomerAction -----> Customer ----------> JDO etc.
| ReqFailException <----DataException
V
ReqFailHandler <global-exception>
|
V
reqfail .jsp
As most(can we say All) of the requests go up to database and any method can
throw exception. SO...
This simple flow cleary shows that EVERY method in _JDO_ MUST be throwing
DataException that CAN be *catched* by _Customer_ and consequently EVERY
method in Customer WILL *throw* nested ReqFailException.
PunchLine: Every method is throwing _exception_ to it's caller.
Note that 2-3 methods in Customer MAY throw additional exception but
ReqFailException will ALWAYS be thrown to Action class.
Is that OK in normal practices?
Looking forward to some replies.
-Navjot Singh
PS - May be i will understand it' use better if you can give me some sample
code ;-)
----- Original Message -----
From: "Andrew Hill" <an...@gridnode.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 5:02 PM
Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
> Generally, returning null when it should be an error is considered bad
> practice. (If null is a valid return value of course thats a different
> matter).
> In this case you should throw an exception and catch it in the calling
class
> and branch or throw again appropriately.
> You dont want your calling class to have to know about low level details
> like specific sql exceptions though, so instead of just letting the sql
> exception propogate upwards, you would catch it and throw a different more
> abstract exception (probably one you create yourself) up to the caller -
the
> caller shouldnt have to know the details about your persistence
mechanism -
> it just needs to know it failed - and sometimes needs to know if the
failure
> is fatal and any other pertinent info.
> The nested excpetion classes should also be able to keep a reference to
the
> exception they wrap so the stacktrace show all the exceptions in the
chain -
> useful when debugging.
>
> btw: If I recall rightly Ted Husted explains this 10 times better in one
> tenth the words in his book (struts in action)
>
> Have a look at these articles:
>
http://developer.java.sun.com/developer/technicalArticles/Programming/except
> ions/
> http://www-106.ibm.com/developerworks/java/library/j-ejb01283.html
> http://www.javaworld.com/javatips/jw-javatip91_p.html
>
> There was another very good one too - but it doesnt seem to be in my
> favourites list and I cant seem to find it now.
>
>
> -----Original Message-----
> From: Navjot Singh [mailto:navjot.s@net4india.net]
> Sent: Thursday, 3 April 2003 18:53
> To: Struts Users Mailing List; andrew.david.hill@gridnode.com
> Subject: Re: Where to catch/throw Exceptions in Struts Tiered
> Architecture
>
>
> hi andrew,
>
> but surely these long stacktraces are not meant for users ;-)
>
> what i have got from your statement is something like this
>
> SQLException
> |__DatabaseException
> |____ApplicationException
>
> finally, this ApplicationException is what is being thrown into execute()
> call.
>
> May i am novice, but I still need to be convinced about throwing so many
> exceptions in chain
>
> Can't the stuff be handled in a simple way --
> SAY
> a. when you get SQLException, catch and return NULL
> b. Calling Class __ifs__ for NULL instead of __catching__ and transfer the
> control accordingly.
>
> Is there something i am ignoring?
>
> regards
> Navjot Singh
>
> ----- Original Message -----
> From: "Andrew Hill" <an...@gridnode.com>
> To: "Struts Users Mailing List" <st...@jakarta.apache.org>
> Sent: Thursday, April 03, 2003 3:49 PM
> Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
>
>
> | I use nested exceptions, and virtually all my methods (and thus layers)
> | catch and wrap and throw...
> | Makes for some impressively long stacktraces - and is marvellous for
> | debugging! :-)
> |
> |
> | -----Original Message-----
> | From: Navjot Singh [mailto:navjot.s@net4india.net]
> | Sent: Thursday, 3 April 2003 18:05
> | To: Struts Users List
> | Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
> |
> |
> | Hi,
> |
> | Take a simple case.
> |
> | Action
> | Y
> | UserAction -> User -> Database
> | |
> | V
> | user.jsp
> |
> | Say, Database throws exception. What is best way to handle exception?
> |
> | 1. Catch in User class and return NULL / some ErrorObject to UserAction
> and
> | let UserAction decide how to handle it?
> |
> | 2. Let User class __pass on__ the Exception from Database to UserAction.
> |
> | 2a. As execute() is already throwing Exception so it will handle ALL so
> Set
> | <global-exception> handler that can send the user to some nice page?
> | 2b. Catch Exception in UserAction and then do some thing ...
> |
> | Which one do you guys follow in not-so-large scale web applications?
> |
> | would appreciate any comments.
> | -navjot singh
> |
> |
> |
> |
> | ---------------------------------------------------------------------
> | To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> | For additional commands, e-mail: struts-user-help@jakarta.apache.org
> |
> |
> | ---------------------------------------------------------------------
> | To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> | For additional commands, e-mail: struts-user-help@jakarta.apache.org
> |
> |
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: struts-user-help@jakarta.apache.org
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: struts-user-help@jakarta.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
RE: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Erica Leung <el...@puremarkets.com>.
Since you guys are having a good discussion on the exceptions handling in
Struts, I would like to ask a lower level question on this topic.
On my JSP I always get a "null" exception something like "[Exception on
\myPage.jsp: null]". At the beginning this exception was very frustrating
since no more details were showing. Now I konw in 90% of the cases, this
exception is from one of the taglibraries. But question is how I can get
more informative details without having a try/catch block on my jsps.
Regards,
Erica
-----Original Message-----
From: Andrew Hill [mailto:andrew.david.hill@gridnode.com]
Sent: Thursday, April 03, 2003 3:33 AM
To: Struts Users Mailing List
Subject: RE: Where to catch/throw Exceptions in Struts Tiered
Architecture
Generally, returning null when it should be an error is considered bad
practice. (If null is a valid return value of course thats a different
matter).
In this case you should throw an exception and catch it in the calling class
and branch or throw again appropriately.
You dont want your calling class to have to know about low level details
like specific sql exceptions though, so instead of just letting the sql
exception propogate upwards, you would catch it and throw a different more
abstract exception (probably one you create yourself) up to the caller - the
caller shouldnt have to know the details about your persistence mechanism -
it just needs to know it failed - and sometimes needs to know if the failure
is fatal and any other pertinent info.
The nested excpetion classes should also be able to keep a reference to the
exception they wrap so the stacktrace show all the exceptions in the chain -
useful when debugging.
btw: If I recall rightly Ted Husted explains this 10 times better in one
tenth the words in his book (struts in action)
Have a look at these articles:
http://developer.java.sun.com/developer/technicalArticles/Programming/except
ions/
http://www-106.ibm.com/developerworks/java/library/j-ejb01283.html
http://www.javaworld.com/javatips/jw-javatip91_p.html
There was another very good one too - but it doesnt seem to be in my
favourites list and I cant seem to find it now.
-----Original Message-----
From: Navjot Singh [mailto:navjot.s@net4india.net]
Sent: Thursday, 3 April 2003 18:53
To: Struts Users Mailing List; andrew.david.hill@gridnode.com
Subject: Re: Where to catch/throw Exceptions in Struts Tiered
Architecture
hi andrew,
but surely these long stacktraces are not meant for users ;-)
what i have got from your statement is something like this
SQLException
|__DatabaseException
|____ApplicationException
finally, this ApplicationException is what is being thrown into execute()
call.
May i am novice, but I still need to be convinced about throwing so many
exceptions in chain
Can't the stuff be handled in a simple way --
SAY
a. when you get SQLException, catch and return NULL
b. Calling Class __ifs__ for NULL instead of __catching__ and transfer the
control accordingly.
Is there something i am ignoring?
regards
Navjot Singh
----- Original Message -----
From: "Andrew Hill" <an...@gridnode.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 3:49 PM
Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
| I use nested exceptions, and virtually all my methods (and thus layers)
| catch and wrap and throw...
| Makes for some impressively long stacktraces - and is marvellous for
| debugging! :-)
|
|
| -----Original Message-----
| From: Navjot Singh [mailto:navjot.s@net4india.net]
| Sent: Thursday, 3 April 2003 18:05
| To: Struts Users List
| Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
|
|
| Hi,
|
| Take a simple case.
|
| Action
| Y
| UserAction -> User -> Database
| |
| V
| user.jsp
|
| Say, Database throws exception. What is best way to handle exception?
|
| 1. Catch in User class and return NULL / some ErrorObject to UserAction
and
| let UserAction decide how to handle it?
|
| 2. Let User class __pass on__ the Exception from Database to UserAction.
|
| 2a. As execute() is already throwing Exception so it will handle ALL so
Set
| <global-exception> handler that can send the user to some nice page?
| 2b. Catch Exception in UserAction and then do some thing ...
|
| Which one do you guys follow in not-so-large scale web applications?
|
| would appreciate any comments.
| -navjot singh
|
|
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
RE: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Andrew Hill <an...@gridnode.com>.
Generally, returning null when it should be an error is considered bad
practice. (If null is a valid return value of course thats a different
matter).
In this case you should throw an exception and catch it in the calling class
and branch or throw again appropriately.
You dont want your calling class to have to know about low level details
like specific sql exceptions though, so instead of just letting the sql
exception propogate upwards, you would catch it and throw a different more
abstract exception (probably one you create yourself) up to the caller - the
caller shouldnt have to know the details about your persistence mechanism -
it just needs to know it failed - and sometimes needs to know if the failure
is fatal and any other pertinent info.
The nested excpetion classes should also be able to keep a reference to the
exception they wrap so the stacktrace show all the exceptions in the chain -
useful when debugging.
btw: If I recall rightly Ted Husted explains this 10 times better in one
tenth the words in his book (struts in action)
Have a look at these articles:
http://developer.java.sun.com/developer/technicalArticles/Programming/except
ions/
http://www-106.ibm.com/developerworks/java/library/j-ejb01283.html
http://www.javaworld.com/javatips/jw-javatip91_p.html
There was another very good one too - but it doesnt seem to be in my
favourites list and I cant seem to find it now.
-----Original Message-----
From: Navjot Singh [mailto:navjot.s@net4india.net]
Sent: Thursday, 3 April 2003 18:53
To: Struts Users Mailing List; andrew.david.hill@gridnode.com
Subject: Re: Where to catch/throw Exceptions in Struts Tiered
Architecture
hi andrew,
but surely these long stacktraces are not meant for users ;-)
what i have got from your statement is something like this
SQLException
|__DatabaseException
|____ApplicationException
finally, this ApplicationException is what is being thrown into execute()
call.
May i am novice, but I still need to be convinced about throwing so many
exceptions in chain
Can't the stuff be handled in a simple way --
SAY
a. when you get SQLException, catch and return NULL
b. Calling Class __ifs__ for NULL instead of __catching__ and transfer the
control accordingly.
Is there something i am ignoring?
regards
Navjot Singh
----- Original Message -----
From: "Andrew Hill" <an...@gridnode.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 3:49 PM
Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
| I use nested exceptions, and virtually all my methods (and thus layers)
| catch and wrap and throw...
| Makes for some impressively long stacktraces - and is marvellous for
| debugging! :-)
|
|
| -----Original Message-----
| From: Navjot Singh [mailto:navjot.s@net4india.net]
| Sent: Thursday, 3 April 2003 18:05
| To: Struts Users List
| Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
|
|
| Hi,
|
| Take a simple case.
|
| Action
| Y
| UserAction -> User -> Database
| |
| V
| user.jsp
|
| Say, Database throws exception. What is best way to handle exception?
|
| 1. Catch in User class and return NULL / some ErrorObject to UserAction
and
| let UserAction decide how to handle it?
|
| 2. Let User class __pass on__ the Exception from Database to UserAction.
|
| 2a. As execute() is already throwing Exception so it will handle ALL so
Set
| <global-exception> handler that can send the user to some nice page?
| 2b. Catch Exception in UserAction and then do some thing ...
|
| Which one do you guys follow in not-so-large scale web applications?
|
| would appreciate any comments.
| -navjot singh
|
|
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
Re: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Navjot Singh <na...@net4india.net>.
hi andrew,
but surely these long stacktraces are not meant for users ;-)
what i have got from your statement is something like this
SQLException
|__DatabaseException
|____ApplicationException
finally, this ApplicationException is what is being thrown into execute()
call.
May i am novice, but I still need to be convinced about throwing so many
exceptions in chain
Can't the stuff be handled in a simple way --
SAY
a. when you get SQLException, catch and return NULL
b. Calling Class __ifs__ for NULL instead of __catching__ and transfer the
control accordingly.
Is there something i am ignoring?
regards
Navjot Singh
----- Original Message -----
From: "Andrew Hill" <an...@gridnode.com>
To: "Struts Users Mailing List" <st...@jakarta.apache.org>
Sent: Thursday, April 03, 2003 3:49 PM
Subject: RE: Where to catch/throw Exceptions in Struts Tiered Architecture
| I use nested exceptions, and virtually all my methods (and thus layers)
| catch and wrap and throw...
| Makes for some impressively long stacktraces - and is marvellous for
| debugging! :-)
|
|
| -----Original Message-----
| From: Navjot Singh [mailto:navjot.s@net4india.net]
| Sent: Thursday, 3 April 2003 18:05
| To: Struts Users List
| Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
|
|
| Hi,
|
| Take a simple case.
|
| Action
| Y
| UserAction -> User -> Database
| |
| V
| user.jsp
|
| Say, Database throws exception. What is best way to handle exception?
|
| 1. Catch in User class and return NULL / some ErrorObject to UserAction
and
| let UserAction decide how to handle it?
|
| 2. Let User class __pass on__ the Exception from Database to UserAction.
|
| 2a. As execute() is already throwing Exception so it will handle ALL so
Set
| <global-exception> handler that can send the user to some nice page?
| 2b. Catch Exception in UserAction and then do some thing ...
|
| Which one do you guys follow in not-so-large scale web applications?
|
| would appreciate any comments.
| -navjot singh
|
|
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
| ---------------------------------------------------------------------
| To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
| For additional commands, e-mail: struts-user-help@jakarta.apache.org
|
|
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
RE: Where to catch/throw Exceptions in Struts Tiered Architecture
Posted by Andrew Hill <an...@gridnode.com>.
I use nested exceptions, and virtually all my methods (and thus layers)
catch and wrap and throw...
Makes for some impressively long stacktraces - and is marvellous for
debugging! :-)
-----Original Message-----
From: Navjot Singh [mailto:navjot.s@net4india.net]
Sent: Thursday, 3 April 2003 18:05
To: Struts Users List
Subject: Where to catch/throw Exceptions in Struts Tiered Architecture
Hi,
Take a simple case.
Action
Y
UserAction -> User -> Database
|
V
user.jsp
Say, Database throws exception. What is best way to handle exception?
1. Catch in User class and return NULL / some ErrorObject to UserAction and
let UserAction decide how to handle it?
2. Let User class __pass on__ the Exception from Database to UserAction.
2a. As execute() is already throwing Exception so it will handle ALL so Set
<global-exception> handler that can send the user to some nice page?
2b. Catch Exception in UserAction and then do some thing ...
Which one do you guys follow in not-so-large scale web applications?
would appreciate any comments.
-navjot singh
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: struts-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: struts-user-help@jakarta.apache.org