[slf4j-user] Java 5 version of SLF4J?

[Erik van Oosten]

Hi Simon,

You should never confuse Java byte code with compiled byte code. I
understand there are a few superfluous byte codes, but in the end the
JVM determines how to compile it to CPU instructions. Unfortunately I am
not aware of what the JVM actually does with unused values. Does it do
escape analysis already?

Regards,
    Erik.


Simon Kitching schreef:
> Erik van Oosten schrieb:
>   
>> Christopher,
>>
>> As I wrote already on Feb 17:
>> 	There is another aproach, as taken by http://code.google.com/p/log5j/. It is
>> 	a wrapper around log4j. I wish they had made it for SLF4J!
>>
>> I am still waiting for someone to this for SLF4J. It should not be hard. I did not yet find the time myself :(
>>   
>>     
>
> Sigh. Broken broken broken.
>
> Re the "feature" for determining which category to create a logger for,
> see the documentation for Exception.getStackTrace. There is no guarantee
> that valid info about the callstack is available. So this code will work
> fine under unit testing, then may start emitting messages to the wrong
> categories when run in a high-performance environment. That will be fun
> to debug...
>
> Re the printf-style formatting:
>
>   log.debug("format str", arg0, arg1, arg2);
>
> is exactly equivalent to:
>
>   push "format str" onto stack
>   tmp = new Object[3];
>   tmp[0] = arg0;
>   tmp[1] = arg1;
>   tmp[2] = arg2;
>   push tmp onto stack
>   invoke log.debug
>   (and of course garbage-collect the tmp object later..)
>
> So in practice, for good performance you need
>   if (log.isDebugEnabled())
> around each call anyway. In which case, the printf-style stuff gives no
> performance benefits at all; if something is going to be logged then the
> formatting is nowhere near the bottleneck step.
>
> The SLF4J fake-varargs approach, where the api allows 0,1 or 2 params is
> slightly better, as it avoids the "new Object[]" call. But for best
> performance, isDebugEnabled should be used anyway.
>
> Regards,
> Simon
>
> _______________________________________________
> user mailing list
> user at slf4j.org
> http://www.slf4j.org/mailman/listinfo/user
>   

-- 

--
Erik van Oosten
http://day-to-day-stuff.blogspot.com/