log4j/log4cxx : exclusive 1 to 1 relation between logger and appender

Question

Using the xml configuration of log4cxx (which is identical in configuration to log4j). I want to have a certain logger output exclusively to a specific appender (have it the only logger which outputs to that appender).

I found that it's possible to bind a logger to a specific appender like this:

<logger name="LoggerName">
    <level value="info"/>
   <appender-ref ref="AppenderName"/>
</logger>

but it that logger still outputs to the root appender because I have this standard piece in the conf file:

<root>
   <priority value="DEBUG"/>
   <appender-ref ref="OtherAppender"/>
</root>

How can I exclude that logger from the root logger? in other words, how do I configure the log such that all loggers inherit the appenders of the root logger except a specific logger?

Answer 1

You use the following piece of configuration for this:

<logger name="TRACER" additivity="false">
    <level value="Debug" />
    <appender-ref ref="DebugAppender" />
</logger>

All loggers with a name that starts with TRACER will log to the appender DebugAppender. For more info, check here or here.

Additivity="false" means messages to this logger will not propogate up the loggers hierarchy so it will not print anything to the root logger.