Log4Simple

Log4Simple.java

import java.util.LinkedList;
import java.nio.charset.Charset;
import java.io.IOException;
import java.io.OutputStream;
import java.io.FileOutputStream;

public class Log4Simple
{
    public enum Level {
	TRACE(0),
	DEBUG(1),
	INFO(2),
	WARN(3),
	ERROR(4),
	FATAL(5);

	private int value;
	
	private Level(int value) {
	    this.value = value;
	}

	public int getValue() {
	    return this.value;
	}
    }

    public abstract class Appender {
	abstract void append(Level level, String message);
    }

    public class FileAppender extends Appender {
	private OutputStream stream;
	private Charset charset;

	FileAppender(OutputStream os, Charset charset) throws IOException {
	    this.charset = charset;
	    this.stream = os;
	}

	FileAppender(String filename, Charset charset) throws IOException {
	    this(new FileOutputStream(filename), charset);
	}

	FileAppender(String filename) throws IOException {
	    this(new FileOutputStream(filename), Charset.forName("UTF-8"));
	}


	void setStream(OutputStream os) {
	    this.stream = os;
	}
	
	@Override
	void append(Level level, String message) {
	    if(this.stream == null) {
		return;
	    }
	    try {
		this.stream.write(message.getBytes(charset));
	    } catch(IOException e) {
		System.err.println("Could not log message");
	    }
	}
    }

    public class ConsoleAppender extends FileAppender {
	public ConsoleAppender(Charset charset) throws IOException {
	    super(System.out, charset);
	}
	
	public ConsoleAppender() throws IOException {
	    this(Charset.forName("UTF-8"));
	}
    }


    private static final LinkedList<Appender> Appenders = new LinkedList<Appender>();
    private static Level level;
    
    public static void addAppender(Appender appender) {
	Appenders.add(appender);
    }

    public static boolean removeAppender(Appender appender) {
	int i = Appenders.indexOf(appender);
	if(i== -1) {
	    return false;
	}
	Appenders.remove(appender);
	return true;
    }

    public static void setLevel(Level lvl) {
	level = lvl;
    }

    public static Level getLevel() {
	return level;
    }
    
    public static void Log(Level lvl, String message) {
	if(level.getValue() >= lvl.getValue()) {
	    for(Appender a : Appenders) {
		a.append(level, message);
	    }
	}
    }
}