logger.java

java 开发的一个电子邮局,挺实用的

/* CVS ID: $Id: Logger.java,v 1.2 2000/04/06 08:02:02 wastl Exp $ */
package net.wastl.webmail.server;

import java.io.*;
import java.util.*;
import java.text.*;
import net.wastl.webmail.misc.*;
import net.wastl.webmail.config.*;

/**
 * Logger.java
 *
 * Created: Sun Sep 19 18:58:28 1999
 *
 * Copyright (C) 1999-2000 Sebastian Schaffert
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
/**
 * This is an asynchronous Logger thread that accepts log messages to a Queue and writes 
 * them to the logfile from time to time (all 5 seconds).
 *
 * @author Sebastian Schaffert
 * @version
 */
public class Logger extends Thread implements ConfigurationListener {
    
    private DateFormat df=null;

    protected PrintWriter logout;
    protected int loglevel;

    protected Queue queue;
    protected Queue time_queue;

    protected boolean do_shutdown=false;

    protected WebMailServer parent;
    protected Storage store;

    protected int interval;

    public Logger(WebMailServer parent, Storage st) {
	this.parent=parent;
	this.store=st;
	parent.getConfigScheme().configRegisterIntegerKey(this,"LOGLEVEL","5",
							  "How much debug output will be written in the logfile");
	parent.getConfigScheme().configRegisterStringKey(this,"LOGFILE",
							 parent.getProperty("webmail.data.path")+
							 System.getProperty("file.separator")+
							 "webmail.log",
							 "WebMail logfile");
	parent.getConfigScheme().configRegisterIntegerKey(this,"LOG INTERVAL","5",
							  "Interval used for flushing the log buffer"+
							  " in seconds. Log messages of level CRIT or"+
							  " ERR will be written immediately in any way.");
	initLog();
	queue=new Queue();
	time_queue=new Queue();
	this.start();
    }
    
    protected void initLog() {
	System.err.print("  * Logfile ... ");
	try {
	    loglevel=Integer.parseInt(store.getConfig("LOGLEVEL"));
	} catch(NumberFormatException e) {}
	try {
	    interval=Integer.parseInt(store.getConfig("LOG INTERVAL"));
	} catch(NumberFormatException e) {}
	try {
	    String filename=store.getConfig("LOGFILE");
	    logout=new PrintWriter(new FileOutputStream(filename,true));
	    System.err.println("initalization complete: "+filename+", Level "+loglevel);
	} catch(IOException ex) {
	    ex.printStackTrace();
	    logout=new PrintWriter(System.out);
	    System.err.println("initalization complete: Sending to STDOUT, Level "+loglevel);
	}
    }	

    protected String formatDate(long date) {
	if(df==null) {
	    TimeZone tz=TimeZone.getDefault();
	    df=DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.DEFAULT, Locale.getDefault());
	    df.setTimeZone(tz);
	}
	String now=df.format(new Date(date));
	return now;
    }

    protected void writeMessage(long time, String message) {
	logout.println("["+formatDate(time)+"] - "+message);
   }
    

    public void log(int level, String message) {
	if(level <= loglevel) {
	    String s="LEVEL "+level;
	    switch(level) {
	    case Storage.LOG_DEBUG: s="DEBUG   "; break;
	    case Storage.LOG_INFO: s="INFO    "; break;
	    case Storage.LOG_WARN: s="WARNING "; break;
	    case Storage.LOG_ERR: s="ERROR   "; break;
	    case Storage.LOG_CRIT: s="CRITICAL"; break;
	    }
	    queue(System.currentTimeMillis(),s+" - "+message);
	    if(level <= Storage.LOG_ERR) {
		flush();
	    }
	}
    }

    protected void flush() {
	while(!queue.isEmpty()) {
	    Long l=(Long)time_queue.next();
	    String s=(String)queue.next();
	    writeMessage(l.longValue(),s);
	}
	logout.flush();
    }	

    public void queue(long time, String message) {
	queue.queue(message);
        time_queue.queue(new Long(time));
    }

    public void notifyConfigurationChange(String key) {
	initLog();
    }	

    public void shutdown() {
	flush();
	do_shutdown=true;
    }

    public void run() {
	while(!do_shutdown) {
	    flush();
	    try {
		sleep(interval*1000);
	    } catch(InterruptedException e) {}
	}
    }
} // Logger