/*********************************************************************
*
* Copyright (C) 2003 Andrew Khan
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
***************************************************************************/
package jxl.common;
import java.security.AccessControlException;
/**
* Abstract wrapper class for the logging interface of choice.
* The methods declared here are the same as those for the log4j
*/
public abstract class Logger
{
/**
* The singleton logger
*/
private static Logger logger = null;
/**
* Factory method to return the logger
*/
public static final Logger getLogger(Class cl)
{
if (logger == null)
{
initializeLogger();
}
return logger.getLoggerImpl(cl);
}
/**
* Initializes the logger in a thread safe manner
*/
private synchronized static void initializeLogger()
{
if (logger != null)
{
return;
}
String loggerName = jxl.common.log.LoggerName.NAME;
try
{
// First see if there was anything defined at run time
loggerName = System.getProperty("logger");
if (loggerName == null)
{
// Get the logger name from the compiled in logger
loggerName = jxl.common.log.LoggerName.NAME;
}
logger = (Logger) Class.forName(loggerName).newInstance();
}
catch(IllegalAccessException e)
{
logger = new jxl.common.log.SimpleLogger();
logger.warn("Could not instantiate logger " + loggerName +
" using default");
}
catch(InstantiationException e)
{
logger = new jxl.common.log.SimpleLogger();
logger.warn("Could not instantiate logger " + loggerName +
" using default");
}
catch (AccessControlException e)
{
logger = new jxl.common.log.SimpleLogger();
logger.warn("Could not instantiate logger " + loggerName +
" using default");
}
catch(ClassNotFoundException e)
{
logger = new jxl.common.log.SimpleLogger();
logger.warn("Could not instantiate logger " + loggerName +
" using default");
}
}
/**
* Constructor
*/
protected Logger()
{
}
/**
* Log a debug message
*/
public abstract void debug(Object message);
/**
* Log a debug message and exception
*/
public abstract void debug(Object message, Throwable t);
/**
* Log an error message
*/
public abstract void error(Object message);
/**
* Log an error message object and exception
*/
public abstract void error(Object message, Throwable t);
/**
* Log a fatal message
*/
public abstract void fatal(Object message);
/**
* Log a fatal message and exception
*/
public abstract void fatal(Object message, Throwable t);
/**
* Log an information message
*/
public abstract void info(Object message);
/**
* Logs an information message and an exception
*/
public abstract void info(Object message, Throwable t);
/**
* Log a warning message object
*/
public abstract void warn(Object message);
/**
* Log a warning message with exception
*/
public abstract void warn(Object message, Throwable t);
/**
* Accessor to the logger implementation
*/
protected abstract Logger getLoggerImpl(Class cl);
/**
* Empty implementation of the suppressWarnings. Subclasses may
* or may not override this method. This method is included
* primarily for backwards support of the jxl.nowarnings property, and
* is used only by the SimpleLogger
*
* @param w suppression flag
*/
public void setSuppressWarnings(boolean w)
{
// default implementation does nothing
}
}
|