Hibernate example source code file (ConnectionProxyHandler.java)

This example Hibernate source code file (ConnectionProxyHandler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

connection, connection, connectionproxyhandler, jdbc, logicalconnectionimplementor, method, object, object, override, override, reflection, sql, sqlexception, sqlexception, statement, string, throwable

The Hibernate ConnectionProxyHandler.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.engine.jdbc.internal.proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Statement;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.engine.jdbc.spi.JdbcResourceRegistry;
import org.hibernate.engine.jdbc.spi.JdbcServices;
import org.hibernate.engine.jdbc.spi.LogicalConnectionImplementor;
import org.hibernate.engine.jdbc.spi.NonDurableConnectionObserver;

import org.jboss.logging.Logger;

/**
 * The {@link InvocationHandler} for intercepting messages to {@link java.sql.Connection} proxies.
 *
 * @author Steve Ebersole
 */
public class ConnectionProxyHandler
		extends AbstractProxyHandler
		implements InvocationHandler, NonDurableConnectionObserver {

    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class,
                                                                       ConnectionProxyHandler.class.getName());

	private LogicalConnectionImplementor logicalConnection;

	public ConnectionProxyHandler(LogicalConnectionImplementor logicalConnection) {
		super( logicalConnection.hashCode() );
		this.logicalConnection = logicalConnection;
		this.logicalConnection.addObserver( this );
	}

	/**
	 * Access to our logical connection.
	 *
	 * @return the logical connection
	 */
	protected LogicalConnectionImplementor getLogicalConnection() {
		errorIfInvalid();
		return logicalConnection;
	}

	/**
	 * Get reference to physical connection.
	 * <p/>
	 * NOTE : be sure this handler is still valid before calling!
	 *
	 * @return The physical connection
	 */
	private Connection extractPhysicalConnection() {
		return logicalConnection.getConnection();
	}

	/**
	 * Provide access to JDBCServices.
	 * <p/>
	 * NOTE : package-protected
	 *
	 * @return JDBCServices
	 */
	JdbcServices getJdbcServices() {
		return logicalConnection.getJdbcServices();
	}

	/**
	 * Provide access to JDBCContainer.
	 * <p/>
	 * NOTE : package-protected
	 *
	 * @return JDBCContainer
	 */
	JdbcResourceRegistry getResourceRegistry() {
		return logicalConnection.getResourceRegistry();
	}

	@Override
    protected Object continueInvocation(Object proxy, Method method, Object[] args) throws Throwable {
		String methodName = method.getName();
        LOG.trace("Handling invocation of connection method [" + methodName + "]");

		// other methods allowed while invalid ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
		if ( "close".equals( methodName ) ) {
			explicitClose();
			return null;
		}

		if ( "isClosed".equals( methodName ) ) {
			return ! isValid();
		}

		errorIfInvalid();

		// handle the JDBC 4 Wrapper#isWrapperFor and Wrapper#unwrap calls
		//		these cause problems to the whole proxy scheme though as we need to return the raw objects
		if ( "isWrapperFor".equals( methodName ) && args.length == 1 ) {
			return method.invoke( extractPhysicalConnection(), args );
		}
		if ( "unwrap".equals( methodName ) && args.length == 1 ) {
			return method.invoke( extractPhysicalConnection(), args );
		}

		if ( "getWrappedObject".equals( methodName ) ) {
			return extractPhysicalConnection();
		}

		try {
			Object result = method.invoke( extractPhysicalConnection(), args );
			result = postProcess( result, proxy, method, args );

			return result;
		}
		catch( InvocationTargetException e ) {
			Throwable realException = e.getTargetException();
			if ( SQLException.class.isInstance( realException ) ) {
				throw logicalConnection.getJdbcServices().getSqlExceptionHelper()
						.convert( ( SQLException ) realException, realException.getMessage() );
			}
			else {
				throw realException;
			}
		}
	}

	private Object postProcess(Object result, Object proxy, Method method, Object[] args) throws SQLException {
		String methodName = method.getName();
		Object wrapped = result;
		if ( "createStatement".equals( methodName ) ) {
			wrapped = ProxyBuilder.buildStatement(
					(Statement) result,
					this,
					( Connection ) proxy
			);
			postProcessStatement( ( Statement ) wrapped );
		}
		else if ( "prepareStatement".equals( methodName ) ) {
			wrapped = ProxyBuilder.buildPreparedStatement(
					( String ) args[0],
					(PreparedStatement) result,
					this,
					( Connection ) proxy
			);
			postProcessPreparedStatement( ( Statement ) wrapped );
		}
		else if ( "prepareCall".equals( methodName ) ) {
			wrapped = ProxyBuilder.buildCallableStatement(
					( String ) args[0],
					(CallableStatement) result,
					this,
					( Connection ) proxy
			);
			postProcessPreparedStatement( ( Statement ) wrapped );
		}
		else if ( "getMetaData".equals( methodName ) ) {
			wrapped = ProxyBuilder.buildDatabaseMetaData( (DatabaseMetaData) result, this, ( Connection ) proxy );
		}
		return wrapped;
	}

	private void postProcessStatement(Statement statement) throws SQLException {
		getResourceRegistry().register( statement );
	}

	private void postProcessPreparedStatement(Statement statement) throws SQLException  {
		logicalConnection.notifyObserversStatementPrepared();
		postProcessStatement( statement );
	}

	private void explicitClose() {
		if ( isValid() ) {
			invalidateHandle();
		}
	}

	private void invalidateHandle() {
        LOG.trace("Invalidating connection handle");
		logicalConnection = null;
		invalidate();
	}

	// ConnectionObserver ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	@Override
	public void physicalConnectionObtained(Connection connection) {
	}

	@Override
	public void physicalConnectionReleased() {
        LOG.logicalConnectionReleasingPhysicalConnection();
	}

	@Override
	public void logicalConnectionClosed() {
        LOG.logicalConnectionClosed();
		invalidateHandle();
	}

	@Override
	public void statementPrepared() {
		// N/A
	}
}