Java Logger

Logger.java

package livedoc.utils;

import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Logger {
	protected static Logger instance;
	
	PrintWriter logFile;
	DateFormat dateFormat;
	long lastLogTime;
	
	protected Logger (String logPath) {
		this.dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		try {
			logFile = new PrintWriter(new FileWriter(logPath + "/livedocLog.txt", true));
		} catch (IOException e) {
			logFile = null;
			e.printStackTrace();
		}
		updateTime();
	}

	protected Logger () {
		this(System.getProperty("user.home"));
	}
	
	protected void finalize() throws Throwable {
		close();
	}	
	
	public static Logger get() {
		if (instance == null) {
			instance = new Logger();
		}
		return instance;
	}
	
	private void updateTime() {
		lastLogTime = System.currentTimeMillis();
	}
	
	public void log(String logger, String log, boolean doProfile) {
        String str = dateFormat.format(new Date()).replace(' ', 'T') + " ";
        if (!logger.isEmpty()) {
        	str += "[" + logger.toUpperCase() + "] ";
        }
        str += log;
        
        if (logFile != null) {
        	logFile.write(str + "\n");
        	logFile.flush();
        } else {
        	System.out.println(str);
        }
        if (doProfile) {
        	updateTime();
        }
	}
	
	public void log(String logger, String log) {
		log(logger, log, true);
	}
	
	public void log(String log) {
		log("", log);
	}
	
	public void profile(String progress) {
		long time = System.currentTimeMillis() - lastLogTime;
		log("profile", progress + " (time: " + time + "ms)");
	}
	
	public void profile() {
		long time = System.currentTimeMillis() - lastLogTime;
		log("profile", "time: " + time + "ms");
	}
	
	public void logException(Exception e) {
		log("error", e.getMessage());
	}
	
	public void close() {
		logFile.close();
		logFile = null;
	}
}

Sample.java

Logger.get().log("ui", "Plugin initialized");


Logger.get().log("debug", "x=" + x);


Logger.get().log("debug", "start to do X");
//do X
Logger.get().profile();    // outputs time spent on X


Logger.get().log("debug", "start to do X,Y,Z");
//do X
Logger.get().profile("X");    // outputs time spent on X
//do Y
Logger.get().profile("Y");    // outputs time spent on Y
//do Z
Logger.get().profile("Z");    // outputs time spent on Z