Hi, I'd offer an extremely simple but usually highly effective heuristic: log it when it's caught. View logging as part of the handling of an exception.
Yoav Shapira Millennium Research Informatics >-----Original Message----- >From: Larry Young [mailto:[EMAIL PROTECTED] >Sent: Tuesday, March 16, 2004 10:34 PM >To: [EMAIL PROTECTED] >Subject: when to log Exceptions > >Hello all, > > This is not exactly a log4j-specific question, but I thought I >would throw it out to this group to get your opinions. > > I have multiple layers in my web-based application, and each layer >has the possibility of throwing exceptions. The question I'm struggling >with is when is it best to log these various Exceptions with the intention >of only logging them once. > > For example, methodA calls methodB which calls methodC and in >there it throws an IOException. Well methodC can't do anything about it so >it simply allows it to propagate up to methodB, which can't actually do >anything about it either, except that it needs to trap for all Exceptions >so that it can release some private assets, and then rethrows it up to >methodA which really doesn't care about it either so it doesn't handle it, >letting it go up to the caller. > > Where would you see as being the best place to log this >Exception? If it gets logged at the lowest layer (methodC), how does the >next layer up (methodB) know not to log it again, since it can't tell which >Exceptions it caused and which were thrown to it. And the same question >applies to methodA? If you only log at the highest layer (methodA's >caller), you lose any ability to turn on/off error logging on a >class-by-class basis. > > Any thoughts on this would be greatly appreciated. Thanks. > >--- regards --- >Larry > > >-------------------------- >Larry Young >The Dalmatian Group >www.dalmatian.com > > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] This e-mail, including any attachments, is a confidential business communication, and may contain information that is confidential, proprietary and/or privileged. This e-mail is intended only for the individual(s) to whom it is addressed, and may not be saved, copied, printed, disclosed or used by anyone else. If you are not the(an) intended recipient, please immediately delete this e-mail from your computer system and notify the sender. Thank you. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
