/*
    * $Id: LoggerService.java 269 2005-08-10 17:49:22Z josem $
    *
    * Tarsis
    * Copyright (C) 2002 Talika Open Source Group
    *
    * 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
   *
   */
  
  package org.talika.tarsis.log;
  
  import java.util.Date;
  import java.text.DateFormat;
  
  import org.talika.tarsis.service.AbstractService;
  
  /**
   * Base implementation of <code>Logger</code> interface.<br>
   * <br>
   * Logger plugs in system like a service by extending <code>AbstractService</code>.
   *
   * @author  Jose M. Palomar
   * @version $Revision: 269 $
   */
  public abstract class LoggerService extends AbstractService implements Logger {
  
      // Constants
      /**
       * Level literals.
       */
      private static final String[] LEVEL_STRINGS = {
                              "debug",
                              "info",
                              "warning",
                              "error",
                              "panic" };
  
      // Fields
      /**
       * Date format.
       */
      private static final DateFormat df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);
  
      /**
       * Logger log level.
       */
      private int logLevel;
  
      // Constructors
      /**
       * Creates a new <code>LoggerService</code>. Default level is <code>WARNING</code>.
       */
      public LoggerService() {
          this(WARNING);
      }
  
      /**
       * Creates a new <code>LoggerService</code> using given log level.
       *
       * @param logLevel int log level.
       */
      public LoggerService(int logLevel) {
          super();
          this.logLevel = logLevel;
      }
  
      // Methods
      /**
       * Returns log level parameter.
       *
       * @return int log level parameter.
       * @see org.talika.tarsis.log.Logger#getLogLevel()
       */
      public int getLogLevel() {
          return logLevel;
      }
  
      /**
       * Sets log level parameter.
       *
       * @param logLevel int log level parameter.
       */
      public void setLogLevel(int logLevel) {
          this.logLevel = logLevel;
      }
  
     /**
      * Returns <code>true</code> if log level is debug or higher.
      *
      * @return boolean <code>true</code> if log level is debug or higher.
      */
     public final boolean isDebugEnabled() {
         return (DEBUG < logLevel);
     }
 
     /**
      * Returns <code>true</code> if log level is info or higher.
      *
      * @return boolean <code>true</code> if log level is info or higher.
      */
     public final boolean isInfoEnabled() {
         return (INFO < logLevel);
     }
 
     /**
      * Returns <code>true</code> if log level is warning or higher.
      *
      * @return boolean <code>true</code> if log level is warning or higher.
      */
     public final boolean isWarningEnabled()  {
         return (WARNING < logLevel);
     }
 
     /**
      * Returns <code>true</code> if log level is error or higher.
      *
      * @return boolean <code>true</code> if log level is error or higher.
      */
     public final boolean isErrorEnabled() {
         return (ERROR < logLevel);
     }
 
     /**
      * Returns <code>true</code> if log level is panic or higher.
      *
      * @return boolean <code>true</code> if log level is panic or higher.
      */
     public final boolean isPanicEnabled()  {
         return (PANIC < logLevel);
     }
 
     /**
      * Log a message using debug level.
      *
      * @param msg String message.
      * @see org.talika.tarsis.log.Logger#logDebug(String)
      */
     public final void logDebug(String msg) {
         log(DEBUG, msg);
     }
 
     /**
      * Log a message using information level.
      *
      * @param msg String message.
      * @see org.talika.tarsis.log.Logger#logInfo(String)
      */
     public final void logInfo(String msg) {
         log(INFO, msg);
     }
 
     /**
      * Log a message using warning level.
      *
      * @param msg String message.
      * @see org.talika.tarsis.log.Logger#logWarning(String)
      */
     public final void logWarning(String msg) {
         log(WARNING, msg);
     }
 
     /**
      * Log an error message using error level.
      *
      * @param msg String message.
      * @param t Throwable a <code>Throwable</code> object.
      * @see org.talika.tarsis.log.Logger#logError(String, Throwable)
      */
     public final void logError(String msg, Throwable t) {
         log(ERROR, msg, t);
     }
 
     /**
      * Log a message using panic level.
      *
      * @param msg String message.
      * @see org.talika.tarsis.log.Logger#logPanic(String)
      */
     public final void logPanic(String msg) {
         log(PANIC, msg);
     }
 
     /**
      * Log an error message using panic level.
      *
      * @param msg String message.
      * @param t Throwable a <code>Throwable</code> object.
      * @see org.talika.tarsis.log.Logger#logPanic(String, Throwable)
      */
     public final void logPanic(String msg, Throwable t) {
         log(PANIC, msg, t);
     }
 
     /**
      * Log a message using given level.
      *
      * @param level int log level.
      * @param msg String message.
      * @see org.talika.tarsis.log.Logger#log(int, String)
      */
     public void log(int level, String msg) {
 
         if (level < logLevel) {
             return;
         }
 
         writeLog(level, formatLog(level, msg, null));
 
     }
 
     /**
      * Log an error message using given level.
      *
      * @param level int log level.
      * @param msg String message.
      * @param t Throwable a <code>Throwable</code> object.
      * @see org.talika.tarsis.log.Logger#log(int, String, Throwable)
      */
     public void log(int level, String msg, Throwable t) {
 
         if (level < logLevel) {
             return;
         }
 
         writeLog(level, formatLog(level, msg, t), t);
 
     }
 
     /**
      * Writes a message to log.
      *
      * @param level int log level.
      * @param msg String message.
      */
     protected abstract void writeLog(int level, String msg);
 
     /**
      * Writes an error message to log.
      *
      * @param level int log level.
      * @param msg String message.
      * @param t Throwable a <code>Throwable</code> object.
      */
     protected abstract void writeLog(int level, String msg, Throwable t);
 
     /**
      * Returns a formatted log message.
      *
      * @param level int log level.
      * @param msg String message.
      * @param t Throwable a <code>Throwable</code> object.
      * @return String formatted log message.
      */
     protected final String formatLog(int level, String msg, Throwable t) {
 
         StringBuffer logMsg = new StringBuffer();
         logMsg.append(df.format(new Date()));
         logMsg.append(" - ");
         logMsg.append(msg);
 
         if (t != null && t.getMessage() != null) {
             logMsg.append(" - ");
             logMsg.append(t.getMessage());
         }
         logMsg.append('\n');
 
         return logMsg.toString();
     }
 
 }