Find out which is the calling method at runtime

Question

Hello.
I have to write a very simple, custom logger. Don't tell me to use logging API, since I can not, unfortunately :-(
In order to log informations I use a class calles FileLogger, which has some methods, like warn(String message), info(String message) which use a private method
void write(String message, int logLevel){
what I'd like to do is to make the method write(String message, int logLevel) log non only the message and the log level, but also the class and the method from which it was called.
How can I do?
Thanks

Answer 1

There is a way to do it - if you only want it when an error occurs, it's fairly easy - and PIFFLE on performance - it only occurs when there's an error (which should be rare!) for pete's sake!
Make it even better and have an if checking a public static final boolean in your error class and you get ZERO overhead if you have logging off - of course you have to change the kode.
-G
import java.io.*;
import java.util.*;
public class A
public static String caller()
ByteArrayOutputStream bs = new ByteArrayOutputStream();
PrintWriter pw = null;
try
throw new Exception("Exc");
catch (Exception e)
e.printStackTrace(new PrintWriter(bs, true));
StringTokenizer st = new StringTokenizer(bs.toString(),"\r\n");
st.nextToken();
st.nextToken();
st.nextToken();
if (!st.hasMoreElements())
return "None";
String theString = st.nextToken();
theString = theString.substring(theString.indexOf(' ')+1);
return theString;
public static void doSomething()
System.out.println("Caller is "+caller());
public static void main(String[] args) throws Exception
doSomething();
System.out.println("Caller is "+caller());
}