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From Peter Donald <>
Subject Re: avalon.ComponentNotAccessibleException
Date Fri, 15 Sep 2000 05:13:48 GMT
At 09:24  14/9/00 +0200, you wrote:
>A good exception-handling framework is given by SAXException which is a
>cascading exception... 

Just FYI a future version of Java will have this functionality built into

>> A notification logger with levels (warning, debug, etc) like the
>> C1 logger is needed to work in conjunction with notifications.
>> Anyway I guess you have in mind a more generic error-handling
>> framework... but Java ha its own, and it works well, IMHO.
>Well, I would have made Exception an interface... but this is because I
>love interfaces :)
>> If you catch errors only to rethrow them, you have a design problem.
>Yes, exactly.

I disagree.

In many cases my code wll look like the following

catch( final Throwable t )
  if( LOG ) LOGGER.warn("Error occured", t );
  throw t;

Then at top level do some generic exception handling.

This allows you some of the benefits of aspect-orientated exception
handling but keeps it standard java and eases debugging.

>> But errors should be more documented: if errors have to be encapsulated
>> to be sent it's not bad at all, as long as you do it in a class that needs
>> a description to get going.
>> In practice, we need a sort on SAX Wrapper interface that accepts
>> NotificableExceptions instead of SAX Exceptions.
>> But this is a big mess, I think.
>> So _final proposal_ (I) make a SAXNotifiableException that implements
>> Notifiable. When you rethrow you add info, and you can throw it
>> as a SAXException, no need to change interfaces.
>> Just have to check in Notifier if it's also instanceOf Notifiable.
>> BTW, if logging is added, shouldn't error handling become a component?

I would prefer to have a base class from which exceptions extend and then
manipulate that.

ie I would like to see a class either AvalonException or CascadingException
that kept reference to root exception. (Actually if you search the archives
that was what I was hinting at re: init() exception handling :P). Both
Avalon and I suspect C2 allow throwing of raw undecorated exceptions which
I really don't like :(. I planned to redo AValon side to be safer in future
but could probably do it now if C2 needs it :P

So what are your thoughts on this ?



| "Nearly all men can stand adversity, but if you want |
| to test a man's character, give him power."          |
|       -Abraham Lincoln                               |

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