[slf4j-user] Should NOPLogger implement org.slf4j.spi.LocationAwareLogger? Dealing with appender startup problem

[Seth Call]

Hi Ceki,

The method in question is this:

public void log(String FQCN, Priority p, Object msg, Throwable t) {
     int levelInt = priorityToLevelInt(p);
     if (locationAwareLogger != null) {
       locationAwareLogger.log(null, FQCN, levelInt, 
convertToString(msg), t);
     } else {
       throw new UnsupportedOperationException("The logger [" + slf4jLogger
           + "] does not seem to be location aware.");
     }
   }

You are right: I only saw this when the logger was the NOPLogger.  I saw 
the UnsupportedOperationException shown in that method was thrown.

What I'm suggesting is that the NOPLogger should implement 
LocationAwareLogger, since I don't see any value in having the NOPLogger 
stop a log from happening...

Thanks,
Seth

On 2/22/10 12:45 AM, Ceki Gulcu wrote:
> Hello Seth,
>
>
> Reading the code of the Category class in log4j-over-slf4j, it appears
> that both loggers of type org.slf4j.Logger *and* LocationAwareLogger
> are supported. Category class in log4j-over-slf4j should throw an
> exception if the slf4j logger it gets is of type NOPLogger. Can you
> show the exception you are observing?
>
> Cheers,
>
> On 22.02.2010 01:57, ownedthx wrote:
>>
>> Hi all,
>>
>> I'm using a logback appender which logs during startup, causing a 
>> NOPLogger
>> to be created while the underlying library initializes.
>>
>> In this specific scenario, I'm coercing a 3rd-party library out of 
>> direct
>> log4j usage by using the log4j-over-slf4j bridge.  However, the
>> Category.java implementation in the bridge will throw an exception if 
>> the
>> underlying logger (in this case, NOPLogger) does not implement the
>> LocationAwareLogger interface.
>>
>> This seems wrong to me--seems to me the NOPLogger should implement
>> LocationAwareLogger, and NOP the log statement specific to that, just 
>> like
>> it does with all the other various log overloads it implements, 
>> instead of
>> causing the appender to fail to start.
>>
>> Any thoughts on this?
>>
>> By the way, I did stop the error by doing just what was recommended 
>> here...
>>
>> Thanks,
>> Seth
>>
>>
>
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