On 13.09.2008, at 12:59, Ceki Gulcu wrote:
Thorbjørn Ravn Andersen wrote:
Ceki Gulcu skrev den 12-09-2008 20:47:
Eric Faden wrote:
Why is there no way to do something like...
logger.error("blah blah {} blah", exception, object);
It seems that the only way to pass that in to the logger is to use
if (logger.isErrorEnabled()) logger.error("blah blah " + object.toString() + " blah", e);
or am I mistaken? It seems that this would be a useful function to make available.
No, you are right. Blame the SLF4J API. Those morons!
I think I'd better elaborate a bit on Ceki's rather brief explanation :)
It is notoriously hard to evolutionarily improve an API and get it exactly right at all the intermediate steps.
The question is how this _could_ be implemented at all without starting looking at the individual objects in a varargs and do stuff depending on their type (essentially putting the method selection in javac based on method signature inside slf4j instead), as there is the vararg putting stuff in a Object array (and exceptions are objects).
If then the last argument is an exception THEN it should be interpreted traditionally with a stacktrace, but then you cannot stuff it in a placeholder (to get the string representation in the message).
What this means is basically that the current syntax breaks down, and perhaps that another approach is appropriate. Feel free to open a JIRA issue if you feel this is important enough.
Pour your information, Joern Huxhorn has already filed a bug report on this topic http://bugzilla.slf4j.org/show_bug.cgi?id=70
-- Ceki Gülcü Logback: The reliable, generic, fast and flexible logging framework for Java. http://logback.qos.ch _______________________________________________ Logback-user mailing list Logback-user@qos.ch http://qos.ch/mailman/listinfo/logback-user
I've recently added that functionality to Lilith ( http://lilith.huxhorn.de/ ) in a pretty transparent way, i.e. the above code would have to look like this: if (logger.isErrorEnabled()) logger.error("blah blah {} blah", object, e); The last argument is used as the Throwable *IF* it is not used up by a placeholder already. So if (logger.isErrorEnabled()) logger.error("blah blah {} blah {}", object, e); would not use e as the Throwable. If you'd like to use both the String representation and the Throwable you'd have to give it as an argument twice if (logger.isErrorEnabled()) logger.error("blah blah {} blah {}", object, e, e); Please keep in mind that e is simply ignored at the moment in case of if (logger.isErrorEnabled()) logger.error("blah blah {} blah", object, e); so I think this is a pretty compatible enhancement. So if you use Lilith and you are using one of the Lilith appenders you'll get what you expect. Joern.