title: Log4j string matching - callback options
body: <p>I am using log4j for my app  logging. Whenever some error messages are logged, i would like to perform some action like sending socket msg/sending traps/db update. I could see that, in log4j, StringMatchFilter or LevelRange Filter can be used to grep the string. But is it possible to register any callback method with log4j which will be invoked upon any string matching? I guess its possible Jamon tool but dont want use a new framework for this simple feature.</p>