LogFactory.java

/*
 Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J is licensed under the terms of the GPLv2
  <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  <http://www.mysql.com/about/legal/licensing/foss-exception.html>.

  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;
		}
	}
}