While writing JavaScript code, I often write debug messages to console using *console.log.* Though it is shorter than *System.out.println()* (hey, you Java!), which I am used to a lot, I still find it ineffective to type it every time.

So, I was following the approach to [bind console.log function to shorter name][1]. Here's another technique which is specific to Sublime Text.

[1]: https://veerasundar.com/blog/shortcut-to-console-log "Shortcut to console.log"

Using Sublime Text *Snippets* option, you can create a shortcut to a template and then you can insert that template in multiple places just by triggering the shortcut. Here's how I did it so that every time, I type *echo*, Sublime Text converts it into *console.log();*

Go to *Tools -> New Snippet*. Sublime will open a template in a new file. Now make sure you have this content in that file (or change it the way you want).

```xml
    <snippet>
    <content><![CDATA[
    console.log(
    ]]></content>
    
    <tabTrigger>echo</tabTrigger> -->
    
    <scope>source.js</scope>
    </snippet>
```

Then save this snippet file as *echo.sublime-snippet* under *Packages/User* folder. To find the location of *Packages/User* folder, in Sublime, go to *Preferences -> Browser packages* and note the location.

Restart sublime and then in a JavaScript file, start typing *echo* and Sublime will provide you with a dropdown to replace *echo* with the template you just created.

Creating a shortcut to console.log in Sublime Text 2


Recently one of my blog reader *Surisetty *send me a question, asking me if it is possible **to write log messages of different levels (info, debug, etc) into different log files**? To answer his question, **yes, it is possible. **We can do this\*\* \*\*by extending the FileAppender class and writing our own logic.

Below is the proof of concept code written to demonstrate this. Before that, you can download the Eclipse project file to run this code in your environment.

[Download the Source code][1]

[1]: http://www.box.net/shared/g3esrz13q4

## To write different log levels in different log files

1.  Create a custom Log4j appender extending _FileAppender._
2.  In that, override the *append() *method and check for the log level before writing a log message. Based on the level, call the *setFile() *method to switch between corresponding log file.
3.  Also, use MDC to store the original log file name mentioned in the _log4j.properties_. This is needed because *setFile() *changes the log file name every time you call it. So, we need to keep a track of the original file name somehow. And, we can use [Log4j MDC][2] for this.

[2]: https://veerasundar.com/blog/log4j-mdc-mapped-diagnostic-context-what-and-why

## Custom Appender: LogLevelFilterFileAppender

```java
    package com.veerasundar.log4j;

    import java.io.File;
    import java.io.IOException;

    import org.apache.log4j.FileAppender;
    import org.apache.log4j.Layout;
    import org.apache.log4j.MDC;
    import org.apache.log4j.spi.ErrorCode;
    import org.apache.log4j.spi.LoggingEvent;

    /**
     * This customized Log4j appender will separate the log messages based on their
     * LEVELS and will write them into separate files. For example, all DEBUG
     * messages will go to a file and all INFO messages will go to a different file.
     *
     * @author Veera Sundar | https://veerasundar.com
     *
     */
    public class LogLevelFilterFileAppender extends FileAppender {

    	private final static String DOT = ".";
    	private final static String HIPHEN = "-";
    	private static final String ORIG_LOG_FILE_NAME = "OrginalLogFileName";

    	public LogLevelFilterFileAppender() {

    	}

    	public LogLevelFilterFileAppender(Layout layout, String fileName,
    			boolean append, boolean bufferedIO, int bufferSize)
    			throws IOException {
    		super(layout, fileName, append, bufferedIO, bufferSize);
    	}

    	public LogLevelFilterFileAppender(Layout layout, String fileName,
    			boolean append) throws IOException {
    		super(layout, fileName, append);
    	}

    	public LogLevelFilterFileAppender(Layout layout, String fileName)
    			throws IOException {
    		super(layout, fileName);
    	}

    	@Override
    	public void activateOptions() {
    		MDC.put(ORIG_LOG_FILE_NAME, fileName);
    		super.activateOptions();
    	}

    	@Override
    	public void append(LoggingEvent event) {
    		try {
    			setFile(appendLevelToFileName((String) MDC.get(ORIG_LOG_FILE_NAME),
    					event.getLevel().toString()), fileAppend, bufferedIO,
    					bufferSize);
    		} catch (IOException ie) {
    			errorHandler
    					.error(
    							"Error occured while setting file for the log level "
    									  event.getLevel(), ie,
    							ErrorCode.FILE_OPEN_FAILURE);
    		}
    		super.append(event);
    	}

    	private String appendLevelToFileName(String oldLogFileName, String level) {
    		if (oldLogFileName != null) {
    			final File logFile = new File(oldLogFileName);
    			String newFileName = "";
    			final String fn = logFile.getName();
    			final int dotIndex = fn.indexOf(DOT);
    			if (dotIndex != -1) {
    				// the file name has an extension. so, insert the level
    				// between the file name and the extension
    				newFileName = fn.substring(0, dotIndex)   HIPHEN   level   DOT
    						  fn.substring(dotIndex   1);
    			} else {
    				// the file name has no extension. So, just append the level
    				// at the end.
    				newFileName = fn   HIPHEN   level;
    			}
    			return logFile.getParent()   File.separator   newFileName;
    		}
    		return null;
    	}
    }
```

## log4j.properties file

```
    log4j.rootLogger = DEBUG, fileout
    log4j.appender.fileout = com.veerasundar.log4j.LogLevelFilterFileAppender
    log4j.appender.fileout.layout.ConversionPattern = %d{ABSOLUTE} %5p %c - %m%n
    log4j.appender.fileout.layout = org.apache.log4j.PatternLayout
    log4j.appender.fileout.File = C:/vraa/temp/logs.log
```

## Let's test our code

```java
    package com.veerasundar.log4j;

    import org.apache.log4j.Logger;

    public class Log4jDemo {

    	private static final Logger logger = Logger.getLogger(Log4jDemo.class);

    	public static void main(String args[]) {
    		logger.debug("This is a debug message");
    		logger.info("This is a information message");
    		logger.warn("This is a warning message");
    		logger.error("This is an error message");
    		logger.fatal("This is a fatal message");
    		logger.debug("This is another debug message");
    		logger.info("This is another information message");
    		logger.warn("This is another warning message");
    		logger.error("This is another error message");
    		logger.fatal("This is another fatal message");
    	}
    }
```


Log4j Tutorial - Writing different log levels in different log files


![How do you use logging in your application?][1]This time, I feel like conducting a poll and hear from you, instead of writing lengthy content. Similar to my other post, [What does it take to make a 'Ëœgood' developer resume?][2], this is also going to be a discussion post. Feel free to cast your vote and leave your comment at the end of this post.

[1]: http://i187.photobucket.com/albums/x201/talktoveera/2999130055_8697986e51.jpg "How do you use logging in your application?"
[2]: https://veerasundar.com/blog/what-does-it-take-to-make-a-good-developer-resume "How to create a good developer resume"

I don't think there is a need to emphasize on the importance of logging in software. Logging helps to maintain a track record of what happened in the application. A good logging framework helps the developer to use logging effectively without affecting the application's performance. For Java applications, [Log4j][3] is always considered as one of the popular logging framework.

[3]: https://veerasundar.com/blog/log4j-tutorial-adding-log4j-logging-to-your-project "Log4j tutorial"

That said about logging, here is the poll for you to vote.

## Logging Framework or No Logging at all?

[poll id="3"]


#log (3)