Hibernate example source code file (DatabaseMetaDataProxyHandler.java)

This example Hibernate source code file (DatabaseMetaDataProxyHandler.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

abstractproxyhandler, connection, connection, connectionproxyhandler, databasemetadataproxyhandler, databasemetadataproxyhandler, invocationtargetexception, jdbc, method, object, object, reflection, resultset, resultset, sql, sqlexception, throwable

The Hibernate DatabaseMetaDataProxyHandler.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.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * The InvocationHandler for intercepting messages to {@link java.sql.DatabaseMetaData} proxies.
 * <p/>
 * Mainly we need to intercept the methods defined on {@link java.sql.DatabaseMetaData} which expose
 * {@link java.sql.ResultSet} instances, which in turn expose {@link java.sql.Statement}
 * instances, which in turn...
 *
 * @author Steve Ebersole
 */
public class DatabaseMetaDataProxyHandler extends AbstractProxyHandler {
	private ConnectionProxyHandler connectionProxyHandler;
	private Connection connectionProxy;
	private DatabaseMetaData databaseMetaData;

	public DatabaseMetaDataProxyHandler(DatabaseMetaData databaseMetaData, ConnectionProxyHandler connectionProxyHandler, Connection connectionProxy) {
		super( databaseMetaData.hashCode() );
		this.connectionProxyHandler = connectionProxyHandler;
		this.connectionProxy = connectionProxy;
		this.databaseMetaData = databaseMetaData;
	}

	protected Object continueInvocation(Object proxy, Method method, Object[] args) throws Throwable {
		// 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( method.getName() ) && args.length == 1 ) {
			return method.invoke( databaseMetaData, args );
		}
		if ( "unwrap".equals( method.getName() ) && args.length == 1 ) {
			return method.invoke( databaseMetaData, args );
		}

		try {
			boolean exposingResultSet = doesMethodExposeResultSet( method );

			Object result = method.invoke( databaseMetaData, args );

			if ( exposingResultSet ) {
				result = ProxyBuilder.buildImplicitResultSet( (ResultSet) result, connectionProxyHandler, connectionProxy );
				connectionProxyHandler.getResourceRegistry().register( ( ResultSet ) result );
			}

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

	protected boolean doesMethodExposeResultSet(Method method) {
		return ResultSet.class.isAssignableFrom( method.getReturnType() );
	}

}