I agree the example doesn't really bring the point across. In the real world
there would be much more debug statements and the LOG.error call would be much
higher in the stack than the place where the error occurs.
Are more typical example might simply be a NullPointerException that is logged
in some outer try-catch-block.
You know the line, where it happened, but you don't know how the variable got
to be null in the first place.
> Maybe your example is too simplistic
> but, I do not see why you
> could not do this for your error log statement:
>
> LOG.error("Could not calculate average age
> for persons: " +persons);
>
> -Ryan
>
> >
> > On 25 August 2010 14:08, Carlos Freund <[email protected]>
> wrote:
> >
> > > Hello,
> > >
> > > I've been using log4j for some time now and it's
> working really fine.
> > > However i have trouble with setting the
> log-levels right.
> > >
> > > I am working on a server that gets quite some
> load.
> > > At first I set the log-level to debug. This was
> very convenient for, well,
> > > debugging. When the server got heavier load this
> got impractical because the
> > > log files would inflate and IO caused by logging
> became noticeable.
> > >
> > > So i set the log level to warn. That solved those
> problems. But now when
> > > the occasional error occurs it has become much
> harder to figure out why.
> > > Before I had the debug statements from which I
> could tell, what was wrong.
> > > Now i just have a Exception and a stacktrace,
> which sometimes just isn't
> > > enough information.
> > >
> > >
> > > So what I'd really like would be a compromise of
> these two options. I was
> > > thinking about a possibility to configure a
> logger so it would add the last
> > > X log
> > > messages of lower levels whenever an log of the
> "regular" level would be
> > > written.
> > >
> > > A Simple example:
> > >
> > > public double getAvgAge(List<Person>
> persons){
> > > LOG.debug("Calulating average age for
> persons: "+persons);
> > > try{
> > > int total_age =
> getTotalAge(persons);
> > > double avg_age = total_age /
> persons.size();
> > > return avg_age;
> > > } catch (Exception e ){
> > > LOG.error("Could not calculate
> average age");
> > > throw e;
> > > }
> > > }
> > >
> > >
> > > I'd like to be able to set up log4j so that
> it doesn't log anyting if the
> > > code works(calls no LOG.error). But when it does
> call LOG.error i'd like to
> > > also see the previous debug statements in my log
> so I can figure out why my
> > > code failed.
> > >
> > > So i would read something like this in my log:
> > > DEBUG AverageAgeCalculator: Calulating average
> age for persons: [ ]
> > > ERROR AverageAgeCalculator: DivideByZeroError
> > > ....stacktrace....
> > >
> > > But no unnecessary statements like:
> > > DEBUG AverageAgeCalculator: Calulating average
> age for persons: [Mary,
> > > Peter ]
> > > DEBUG AverageAgeCalculator: Calulating average
> age for persons: [Carlos,
> > > Hans, Klaus]
> > >
> > >
> > > I happen to have some free time on my hands so
> i'd like to try to code this
> > > myself.
> > > But before i start thinking about implementation,
> I would like to know some
> > > things.
> > >
> > > Does something like this already exist?
> > > Do you think this would be useful?
> > >
> > > Greetings, Carlos Freund
> > >
> > >
> > >
> > >
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> > > For additional commands, e-mail: [email protected]
> > >
> > >
> >
>
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