Re: Basic Question about Loggers, Parent Loggers, and Levels
On Apr 30, 12:59 am, markspace <nos...@nowhere.com> wrote:
Rhino wrote:
Anything you can tell me about what I need to do differently would be
GREATLY appreciated!
That ran ok for me. It would be helpful if I knew what output you were
expecting to see, since it isn't obvious what you consider to be wrong
there.
As you can see in the code, Alpha writes one log record for each of
the seven severity levels to each of the two logs, master and project
(or parent and child if you prefer). All of the messages written
DIRECTLY to the child, which had a level of ALL set, were indeed
captured in the child log as expected. The parent log is set to a
level of WARNING so should only capture WARNING and SEVERE records.
However, it is getting copies of ALL of the records written to the
child, including ones that are FINEST, FINER, FINE, CONFIG and INFO.
That is definitely contrary to my expectations! I had assumed that
setting the parent logger to WARNING would ensure that only child
records that were WARNING and SEVERE would make it into the parent
log.
Alpha also writes one message of each severity level DIRECTLY to the
parent logger. In this case, only the WARNING and SEVERE records
appear in the parent log. The level set for the logger only appears to
work correctly when the message is written directly to the parent
logger but not have any effect on messages passed up from child
loggers.
Writing directly to the parent logger was only an experiment to
understand the problem. It seems to me that if the child logger is
supposed to pass up only qualifying messages to the parent logger,
then an application should never write directly to the parent logger.
Am I completely misunderstanding how this logging stuff is supposed to
work, especially the relationship between parent and child loggers?
The other thing that baffles me is the Filter. Despite having put the
filter on both the parent logger (via the code) and the FileHandler
for the parent logger (via the logging.properties file), it doesn't
actually seem to do very much; it is certainly _not_ keeping FINEST,
FINER, FINE, CONFIG and INFO records out of the parent log. I'm also
suprised by the displays I'm getting on the console. I had expected
the Filter to evaluate all seven records generated for the child
logger but I'm only getting displays for WARNING and SEVERE records.
It correctly evaluates those as being loggable but it never actually
seems to see the lower severities. It looks as if, at some level, the
lower severity records aren't even getting to the Filter, having been
screened out somehow, yet ALL severities of records ultimately appear
in the parent log, despite the levels which have been set or the
Filters which are in place.
Again, I may have a major misundertanding of what is supposed to be
happening. That's why I posted. Or I may just have a coding error in
the Filter that keeps it from working the way I would expect. I'm
trying to keep an open mind ;-)
I did make at least one mistake: loggers do NOT pass log messages to
their parent if their log level is set higher than the log message's leve=
l:
public class LoggerTest
{
public static void main( String[] args )
{
Logger parentLogger = Logger.getLogger( "x.y" );
Logger childLogger = Logger.getLogger( "x.y.z" );
ConsoleHandler parentHandler = new ConsoleHandler();
parentHandler.setLevel( Level.ALL );
parentLogger.addHandler( parentHandler );
ConsoleHandler childHandler = new ConsoleHandler();
childHandler.setLevel( Level.INFO );
childLogger.addHandler( childHandler );
parentLogger.setLevel( Level.ALL );
childLogger.setLevel( Level.INFO ); // change here
childLogger.finest( "test" ); // doesn't log
}
}
This does not log any message. Change the 2nd to last line with
"childLogger.setLevel" to see one log message. Change the childLogger'=
s
consoleHandler in addition to see two.
This is interesting. I'm working with your program and trying umpteen
variations to see what happens. I think I'm going to understand
logging a lot better when I'm done :-) I'll post back here once I've
tried a bunch of these variations.....
--
Rhino