log4j NDC

Here is a link about logging best practices:  http://c2.com/cgi/wiki?LoggingBestPractices

The last rule of thumb:

If you're logging the output of a web service or something like that, make sure you log an item which is unique to the session in each log message. With log4j, you can do this using a NDC. (We didn't use the session id, thats too long, we grabbed a unique integer and put it into the session). This way you can trace whats happening to a single session very easily. You can also log the request parameters as well if you're concerned about that sort of thing

for more about NDC, please see: http://lstierneyltd.com/blog/development/log4j-nested-diagnostic-contexts-ndc/ and http://www.vipan.com/htdocs/log4jhelp.html

for code sample:




public ReturnType method( InputType input) throws ExceptionType{




      NDC.push("identifyme");

      try {

         // do something

      } catch(ExceptionType e) {

         throw e;

      } finally {

         NDC.pop();

      }

}

NDC javadoc here: http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/NDC.html