Log.java

/* Copyright (c) 2014 Jesper Öqvist <jesper@llbit.se>
 *
 * This file is part of Chunky.
 *
 * Chunky 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 3 of the License, or
 * (at your option) any later version.
 *
 * Chunky 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 Chunky.  If not, see <http://www.gnu.org/licenses/>.
 */
package se.llbit.log;

/**
 * Simple logging framework.
 *
 * <p>The default log level is "WARNING". The default log level can be changed
 * by adding -DlogLevel=INFO to the Java command line.
 */
public class Log {

  public static Level level = Level.WARNING;
  private static final int INFO = Level.INFO.ordinal();
  private static final int WARNING = Level.WARNING.ordinal();
  private static final int ERROR = Level.ERROR.ordinal();
  private static final Receiver[] receiver =
      {ConsoleReceiver.INSTANCE, ConsoleReceiver.INSTANCE, ConsoleReceiver.INSTANCE};

  static {
    try {
      level = Level.valueOf(System.getProperty("logLevel", "WARNING"));
    } catch (IllegalArgumentException e) {
      // Ignored.
    }
  }

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

  public static void setReceiver(Receiver receiver, Level... levels) {
    if (receiver == null) {
      throw new IllegalArgumentException("Can't set a null receiver.");
    }
    if (levels == null || levels.length == 0) {
      throw new IllegalArgumentException("No log level specified for receiver.");
    }
    for (Level level : levels) {
      Log.receiver[level.ordinal()] = receiver;
    }
  }

  public static void infof(String fmt, Object... args) {
    if (level == Level.INFO) {
      receiver[INFO].logEvent(Level.INFO, String.format(fmt, args));
    }
  }

  public static void info(String message) {
    if (level == Level.INFO) {
      receiver[INFO].logEvent(Level.INFO, message);
    }
  }

  public static void info(String message, Throwable thrown) {
    if (level == Level.INFO) {
      receiver[INFO].logEvent(Level.INFO, message, thrown);
    }
  }

  public static void warnf(String fmt, Object... args) {
    if (level != Level.ERROR) {
      receiver[WARNING].logEvent(Level.WARNING, String.format(fmt, args));
    }
  }

  public static void warn(String message) {
    if (level != Level.ERROR) {
      receiver[WARNING].logEvent(Level.WARNING, message);
    }
  }

  public static void warn(String message, Throwable thrown) {
    if (level != Level.ERROR) {
      receiver[WARNING].logEvent(Level.WARNING, message, thrown);
    }
  }

  public static void errorf(String fmt, Object... args) {
    receiver[ERROR].logEvent(Level.ERROR, String.format(fmt, args));
  }

  public static void error(String message) {
    receiver[ERROR].logEvent(Level.ERROR, message);
  }

  public static void error(String message, Throwable thrown) {
    receiver[ERROR].logEvent(Level.ERROR, message, thrown);
  }

  public static void error(Throwable thrown) {
    receiver[ERROR].logEvent(Level.ERROR, thrown);
  }

}