logfactory.java

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/*
      Copyright (C) 2002-2004 MySQL AB

      This program is free software; you can redistribute it and/or modify
      it under the terms of version 2 of the GNU General Public License as 
      published by the Free Software Foundation.

      There are special exceptions to the terms and conditions of the GPL 
      as it is applied to this software. View the full text of the 
      exception in file EXCEPTIONS-CONNECTOR-J in the directory of this 
      software distribution.

      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 com.mysql.jdbc.log;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.sql.SQLException;

import com.mysql.jdbc.SQLError;

/**
 * Creates instances of loggers for the driver to use.
 * 
 * @author Mark Matthews
 * 
 * @version $Id: LogFactory.java,v 1.1.2.4 2004/08/12 20:28:31 mmatthew Exp $
 */
public class LogFactory {
	
	/**
	 * Returns a logger instance of the given class, with the
	 * given instance name.
	 * 
	 * @param className the class to instantiate
	 * @param instanceName the instance name
	 * @return a logger instance
	 * @throws SQLException if unable to create a logger instance
	 */
	public static Log getLogger(String className, String instanceName) 
		throws SQLException {
		
		if (className == null) {
			throw new SQLException("Logger class can not be NULL", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}
		
		if (instanceName == null) {
			throw new SQLException("Logger instance name can not be NULL", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}
				
		try {
			Class loggerClass = Class.forName(className);
			Constructor constructor = loggerClass.getConstructor(new Class[] {String.class});
			
			return (Log) constructor.newInstance(new Object[] {instanceName});
		} catch (ClassNotFoundException cnfe) {
			throw new SQLException("Unable to load class for logger '" + className + "'", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		} catch (NoSuchMethodException nsme) {
			throw new SQLException("Logger class does not have a single-arg constructor that takes an instance name", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		} catch (InstantiationException inse) {
			throw new SQLException("Unable to instantiate logger class '" + className + "', exception in constructor?", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		} catch (InvocationTargetException ite) {
			throw new SQLException("Unable to instantiate logger class '" + className + "', exception in constructor?", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		} catch (IllegalAccessException iae) {
			throw new SQLException("Unable to instantiate logger class '" + className + "', constructor not public", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		} catch (ClassCastException cce) {
			throw new SQLException("Logger class '" + className + "' does not implement the '" + Log.class.getName() + "' interface", SQLError.SQL_STATE_ILLEGAL_ARGUMENT);
		}
	}
}