snippit of code for grabbing the stack/filename/lines in GWT

Log.java

public class Log {


  /*
  *  type - is "INFO", "DEBUG",  "ERROR" etc
  *  object - is an "id" of the person calling it.  as a convention, I use 'this' unless it is a static method, then I pass in the class
  *  msg - the log message
  */
	public static void log(String type, Object object, String msg) {
		String name;
		if (object instanceof String) {
			name = (String) object;
		} else {
			Class<? extends Object> clazz = null;
			if ((object instanceof Class)) {
				clazz = (Class<? extends Object>) object;
			} else {
				if (object == null) {  
					name = "?";  
					// default - stop outside/up one - i never use this path
					clazz = Log.class;
				} else {
					clazz = object.getClass();
				}
			}
			name = clazz.getName();
			//after means we show then next matching element - eg, it is not interesting to see the line in the logger!
			boolean after = Log.class.equals(clazz);

			// name is now a class - lookup the line number
			String line = findLineAndMethodInStack(name, after);

      if (line!=null)
			  name += ":" + line;
		}

		String text = getTimeStamp() + " " + type + ": " + name + " : " + msg;


    //these are my 'appenders' - you could just use GWT.log(text) or System.out.println(text);
		if (SERVER_LOG)
			new LogEvent().type(type).location(name).message(msg).user(user).fire();

		if (GWT.isProdMode()) {
		  //these do stuff with chrome logger colors
			nativeLog(type, text);
		} else {
		  //ansi colors 
			String color = typeToColorMap.get(type);
			System.out.println(color + text + Color.RESET);
		}
	}



	private static String findLineAndMethodInStack(String name, boolean after) {
		String[] parts = name.split("\\.");
		//get rid of the package
		name = parts[parts.length - 1];
		
		//mildly complicated because of the 'after' (ie nextMatch) logic
		boolean wasMatched = false;
		
		StackTraceElement[] stack = new RuntimeException().getStackTrace();
		for (StackTraceElement e : stack) {
			String stackName = e.getFileName().replace(".java", "");
			boolean isMatch = stackName.equals(name);
			
			if (after) {
			  //check the next match logic
				if (isMatch) {
				  //don't match yet, wait until it changes
					isMatch = false;
					wasMatched = true;
				} else if (wasMatched && !isMatch)
				  //it must have changed, and we had a match before, so use this one 
					isMatch = true;
			}
			
			if (isMatch) {
				String lineAndMethod = e.getLineNumber() + " (" + e.getMethodName()+ ")";
				if (stackName.equals(name))
					// exact match, so don't need the name
					return ":" + lineAndMethod;
				else
					// name is something like Log.java, so we want to return the
					// actual file name
					return " " + stackName + ":" + lineAndMethod;
			}
		}
		return null;
	}

use it like this:

Log.log("DEBUG",this,"hey there, we are logging this");

I create a bunch of wrappers, so I can call

Log.debug(this,"hey there, debuggery!");