Re: Exception Handling
On 3/11/2012 2:54 PM, Novice wrote:
Lew<noone@lewscanon.com> wrote in news:jjipli$np7$1@news.albasani.net:
....
It is common and frequently useful to create an application-specific
checked exception. Again, and I've said this many times, think about
what will be useful when troubleshooting a problem. Many times, a
custom exception is useful. It says that the underlying exception has
been caught, logged and wrapped.
But how is a custom FooException better than a good ol'
IllegalArgumentException? I'm not quite getting that yet.
Generally, you should use different Exception subclasses for cases that
may need different handling, so that callers can set up appropriate
catch blocks.
Regardless of the conditions under which you choose to generate
IllegalArgumentException, many methods you will be calling use it to
indicate an illegal argument condition that has not yet been logged or
otherwise reported.
If you also use it to indicate exceptions that have already been logged,
you risk either repeated logging of the same issue, or failure to log.
On the other hand, if you create an Exception subclass that you only
throw after logging the underlying problem, there is no ambiguity.
Callers have to deal with the consequences of the failure, but should
only generate log messages if they have something to add. The underlying
problem has already been logged.
Patricia