LogFactory.java

/*
 Copyright  2002-2007 MySQL AB, 2008 Sun Microsystems
 All rights reserved. Use is subject to license terms.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.com.

  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; version 2 of the
  License.

  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 St, Fifth Floor, Boston, MA
  02110-1301 USA



 */
package com.mysql.jdbc.log;

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

import com.mysql.jdbc.ExceptionInterceptor;
import com.mysql.jdbc.SQLError;

/**
 * Creates instances of loggers for the driver to use.
 * 
 * @author Mark Matthews
 * 
 * @version $Id$
 */
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, ExceptionInterceptor exceptionInterceptor)
			throws SQLException {

		if (className == null) {
			throw SQLError.createSQLException("Logger class can not be NULL",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
		}

		if (instanceName == null) {
			throw SQLError.createSQLException(
					"Logger instance name can not be NULL",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
		}

		try {
			Class loggerClass = null;

			try {
				loggerClass = Class.forName(className);
			} catch (ClassNotFoundException nfe) {
				loggerClass = Class.forName(Log.class.getPackage().getName()
						+ "." + className);
			}

			Constructor constructor = loggerClass
					.getConstructor(new Class[] { String.class });

			return (Log) constructor.newInstance(new Object[] { instanceName });
		} catch (ClassNotFoundException cnfe) {
			SQLException sqlEx = SQLError.createSQLException(
					"Unable to load class for logger '" + className + "'",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(cnfe);

			throw sqlEx;
		} catch (NoSuchMethodException nsme) {
			SQLException sqlEx = SQLError
					.createSQLException(
							"Logger class does not have a single-arg constructor that takes an instance name",
							SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(nsme);

			throw sqlEx;
		} catch (InstantiationException inse) {
			SQLException sqlEx = SQLError.createSQLException(
					"Unable to instantiate logger class '" + className
							+ "', exception in constructor?",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(inse);

			throw sqlEx;
		} catch (InvocationTargetException ite) {
			SQLException sqlEx = SQLError.createSQLException(
					"Unable to instantiate logger class '" + className
							+ "', exception in constructor?",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(ite);

			throw sqlEx;
		} catch (IllegalAccessException iae) {
			SQLException sqlEx = SQLError.createSQLException(
					"Unable to instantiate logger class '" + className
							+ "', constructor not public",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(iae);

			throw sqlEx;
		} catch (ClassCastException cce) {
			SQLException sqlEx = SQLError.createSQLException("Logger class '"
					+ className + "' does not implement the '"
					+ Log.class.getName() + "' interface",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
			sqlEx.initCause(cce);

			throw sqlEx;
		}
	}
}