Log4j Wrapper and PatternLayout Implementation

[Viji San]

Hello, As per my requirement, I need to use something like MyAppLogger in all my class to get log4j logger. As suggested in log4j Complete manual, I decided to use Wrapper class to get log4j Logger. Please look at my Wrapper class below.

  package com.logger.test;

import org.apache.log4j.Logger;

public class MyAppLogger {

	private Logger logger = null;
	
	@SuppressWarnings("unchecked")
	public MyAppLogger(Class clazz)
	{
		this.logger = Logger.getLogger(clazz);
	}
	
	public void fatal(Object message) {
		
		logger.fatal(message);
	}
	
	public void fatal (Object message, Throwable t) 
	{
		logger.fatal(message, t);
	}
	
	public void error (Object message)
	{
		logger.error(message);
	}
	
	public void error (Object message, Throwable t)
	{
		logger.error(message, t);
	}

	public void warn (Object message)
	{
		logger.warn(message);
	}
	
	public void warn (Object message, Throwable t)
	{
		logger.warn(message, t);
	}
	
	public void info (Object message)
	{
		logger.info(message);
	}
	
	public void info (Object message, Throwable t)
	{
		logger.info(message, t);
	}
	
	public void debug (Object message)
	{
		logger.debug(message);
	}
	
	public void debug (Object message, Throwable t)
	{
		logger.debug(message, t);
	}

	public void trace (Object message, Throwable t)
	{
		logger.trace(message, t);
	}
	
	public void trace (Object message)
	{
		logger.trace(message);
	}
	
	
	public boolean isDebugEnabled ()
	{
		return logger.isDebugEnabled();
			
	}
	
}
  

Now, the next requirement is to prefix "Timestamp, threadId, Class name, Method name" to the actual log message. I configured PatternLayout in log4j.xml config file as mentioned below

  <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration threshold="all" debug="false"  xmlns:log4j="http://jakarta.apache.org/log4j/">

 <!-- Console application log  -->
 <appender name="consoleAppender" class="org.apache.log4j.ConsoleAppender">
  <layout class="org.apache.log4j.PatternLayout">
   <param name="ConversionPattern" value="%d{ISO8601}  %-5p %t - %C.%M: %m%n"/>
  </layout>
 </appender> 

 <!--   Root Logger -->
   <root> 
    <priority value ="debug" /> 
    <appender-ref ref="consoleAppender" /> 
  </root>
 
 
</log4j:configuration>  

This is my logger test class:

  package com.logger.test;

import org.apache.log4j.xml.DOMConfigurator;

public class LoggerTest {
	
	public static void main(String[] args) {
		
		DOMConfigurator.configure("C:\\log4j.xml");
		
		MyAppLogger logger = new MyAppLogger (LoggerTest.class);
		logger.debug("Logging Pattern Layout Sample Message.....");
	}
}
  

The output is below:

  2010-10-26 12:39:25,232  DEBUG main - com.logger.test.MyAppLogger.debug: Logging Pattern Layout Sample Message.....
  

The result is expected to show up Class name and method name where logging message is created. But what happens here is, as I use logger wrapper, the class name and method name is always com.logger.test.MyAppLogger.debug/info/warn/error. This is not the behavior which I need. How could I correct ? Should I remove wrapper and extend log4j Logger class? What would be the best approach? Please advise me.

[Carol Enderlin]

I'm not sure why you are using wrapper, but looking at the complete log4j manual that you mention...you are not using a critical part of what is suggested.

The mysterious FCQN variable, declared at the start of MyLogger class, helps log4j to obtain the correct localization information...without it log4j will...think that MyLogger is the caller instead of the class which really invoked a MyLogger instance.

Then the usage of the log method with FQCN is shown. Partial Example :

 logger.log(FQCN, Level.DEBUG, msg, null);   

Edit: typo in the code from complete manual, I could not copy from the pdf.

[Viji San]

Thank you so much!! I missed a VERY important point.