Re: About java program.
On 7/6/2013 7:14 AM, Robert Klemme wrote:
On 06.07.2013 10:16, lipska the kat wrote:
The important word here is *may* ... what happens if the caller decides
to ignore the exception, or maybe handle it without recording the
reason. What are you left with ...
Well, you can forget the logging on *any* level of the application.
There is no really a difference between asking the author of this method
to do proper error handling or asking the author of some other code to
do it.
The example is trivial I agree but the concept is sound.
If you do that kind of logging in all sorts of methods you'll end up
with extreme volumes of logfiles that make it hard to detect real bugs
and cost significant IO.
In all my years working with log4j log files I have never felt that
it was a problem with too much logged but often cursed that they did
not log exactly what I needed.
For anything except the most trivial apps the log files are too big
to just read top down. You need to use tools: editor find, grep,
special log tools, whatever.
And then it really doe snot matter of it is 1 MB, 10 MB, 100 MB or 1 GB.
And log files are sequentially written text files. Logging a MB per hour
has very little performance impact today.
IMHO it is bad practice *not* to log the error at the point of origin.
The point is: you do not know whether it _is_ an error inside this
method. You know arguments violate the contract, but you do not know
whether that poses a problem for the program.
Correct.
Hence: throw an exception
and be done.
No.
Logging is not intended only to be used for errors.
If we look at log4j log levels:
fatal
error
warn
info
debug
trace
then I agree that because we do not know if it is an error, then
we should not use the first 2 levels, but that leaves 4 levels
as potential candidates for level.
jul has similar multiple levels.
Arne