LogLevel.java

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/*
    Calimero - A library for KNX network access
    Copyright (C) 2006-2008 B. Malinowsky

    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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA. 
 
    Linking this library statically or dynamically with other modules is 
    making a combined work based on this library. Thus, the terms and 
    conditions of the GNU General Public License cover the whole 
    combination. 
 
    As a special exception, the copyright holders of this library give you 
    permission to link this library with independent modules to produce an 
    executable, regardless of the license terms of these independent 
    modules, and to copy and distribute the resulting executable under terms 
    of your choice, provided that you also meet, for each linked independent 
    module, the terms and conditions of the license of that module. An 
    independent module is a module which is not derived from or based on 
    this library. If you modify this library, you may extend this exception 
    to your version of the library, but you are not obligated to do so. If 
    you do not wish to do so, delete this exception statement from your 
    version. 
*/

package tuwien.auto.calimero.log;

/**
 * Defines different log levels.
 * <p>
 * Defines several severity levels used to categorize logging information and
 * loggers. It also gives a clue about the chattiness of the respective object.
 * 
 * @author B. Malinowsky
 */
public class LogLevel
{
	private static final int LOG_OFF = 0;
	private static final int LOG_FATAL = 100;
	private static final int LOG_ERROR = 200;
	private static final int LOG_WARN = 300;
	private static final int LOG_INFO = 400;
	private static final int LOG_TRACE = 500;
	private static final int LOG_ALL = 1000;

	/**
	 * The lowest log level, logging is turned off.
	 */
	public static final LogLevel OFF = new LogLevel(LOG_OFF);
	/**
	 * This level identifies the attached object for fatal errors purposes.
	 */
	public static final LogLevel FATAL = new LogLevel(LOG_FATAL);
	/**
	 * This level identifies the attached object for errors purposes.
	 */
	public static final LogLevel ERROR = new LogLevel(LOG_ERROR);
	/**
	 * This level identifies the attached object for warning purposes.
	 */
	public static final LogLevel WARN = new LogLevel(LOG_WARN);
	/**
	 * This level identifies the attached object for informational purposes.
	 */
	public static final LogLevel INFO = new LogLevel(LOG_INFO);
	/**
	 * This level identifies the attached object for tracing purposes.
	 */
	public static final LogLevel TRACE = new LogLevel(LOG_TRACE);
	/**
	 * The highest log level, no restrictions, everything will be logged.
	 */
	public static final LogLevel ALL = new LogLevel(LOG_ALL);

	final int level;

	/**
	 * Creates a new LogLevel object with <code>logLevel</code> assigned to it.
	 * @param logLevel log level represented by this object
	 */
	protected LogLevel(int logLevel)
	{
		level = logLevel;
	}

	/**
	 * Compares for a higher log level than <code>l</code>.
	 * <p>
	 * 
	 * @param l level to compare
	 * @return true iff this object has a higher log level than <code>l</code>.
	 */
	public final boolean higher(LogLevel l)
	{
		return level > l.level;
	}

	/**
	 * Compares the log level with <code>obj</code>.
	 * <p>
	 * 
	 * @param obj {@inheritDoc}
	 * @return <code>true</code> if <code>o</code> is of type
	 *         <code>LogLevel</code> and has the same log level as this object,
	 *         <code>false</code> otherwise.
	 */
	public boolean equals(Object obj)
	{
		if (obj instanceof LogLevel)
			return ((LogLevel) obj).level == level;
		return false;
	}

	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	public int hashCode()
	{
		final int offset = 435273;
		return level + offset;
	}

	/**
	 * Returns the log level in textual format, like "off", "trace",
	 * . . .  or "unknown" if level is not defined.
	 * 
	 * @return the log level as string
	 */
	public String toString()
	{
		switch (level) {
		case LOG_OFF:
			return "off";
		case LOG_TRACE:
			return "trace";
		case LOG_INFO:
			return "info";
		case LOG_WARN:
			return "warn";
		case LOG_ERROR:
			return "error";
		case LOG_FATAL:
			return "fatal";
		case LOG_ALL:
			return "all";
		default:
			return "unknown";
		}
	}
}