WrapperBase.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.jdbc2.optional;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.SQLException;
import java.util.Map;

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

/**
 * Base class for all wrapped instances created by LogicalHandle
 * 
 * @author Mark matthews
 * 
 * @version $Id$
 */
abstract class WrapperBase {
	protected MysqlPooledConnection pooledConnection;

	/**
	 * Fires connection error event if required, before re-throwing exception
	 * 
	 * @param sqlEx
	 *            the SQLException that has ocurred
	 * @throws SQLException
	 *             (rethrown)
	 */
	protected void checkAndFireConnectionError(SQLException sqlEx)
			throws SQLException {
		if (this.pooledConnection != null) {
			if (SQLError.SQL_STATE_COMMUNICATION_LINK_FAILURE.equals(sqlEx
					.getSQLState())) {
				this.pooledConnection.callConnectionEventListeners(
						MysqlPooledConnection.CONNECTION_ERROR_EVENT, sqlEx);
			}
		}

		throw sqlEx;
	}
	
	protected Map unwrappedInterfaces = null;
	protected ExceptionInterceptor exceptionInterceptor;

	protected WrapperBase(MysqlPooledConnection pooledConnection) {
		this.pooledConnection = pooledConnection;
		this.exceptionInterceptor = this.pooledConnection.getExceptionInterceptor();
	}
	
	protected class ConnectionErrorFiringInvocationHandler implements InvocationHandler {
		Object invokeOn = null;
		
		public ConnectionErrorFiringInvocationHandler(Object toInvokeOn) {
			invokeOn = toInvokeOn;
		}
		
		public Object invoke(Object proxy, Method method,
				Object[] args) throws Throwable {
			Object result = null;

			try {
				result = method.invoke(invokeOn, args);
				
				if (result != null) {
					result = proxyIfInterfaceIsJdbc(result, 
							result.getClass());
				}
			} catch (InvocationTargetException e) {
				if (e.getTargetException() instanceof SQLException) {
					checkAndFireConnectionError((SQLException) e
							.getTargetException());
				} else {
					throw e;
				}
			}

			return result;
		}
		
		/**
		 * Recursively checks for interfaces on the given object to determine
		 * if it implements a java.sql interface, and if so, proxies the 
		 * instance so that we can catch and fire SQL errors.
		 * @param toProxy
		 * @param clazz
		 * @return
		 */
		private Object proxyIfInterfaceIsJdbc(Object toProxy, Class<?> clazz) {
			Class<?>[] interfaces = clazz.getInterfaces();
			
			for (Class<?> iclass : interfaces) {
				String packageName = iclass.getPackage().getName();
				
				if ("java.sql".equals(packageName) || 
						"javax.sql".equals(packageName)) {
					return Proxy.newProxyInstance(toProxy.getClass()
							.getClassLoader(), interfaces,
							new ConnectionErrorFiringInvocationHandler(toProxy));
				}
				
				return proxyIfInterfaceIsJdbc(toProxy, iclass);
			}
			
			return toProxy;
		}
	}
}