Hibernate example source code file (DialectFactoryImpl.java)

This example Hibernate source code file (DialectFactoryImpl.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, could, dialect, dialect, dialectfactory, dialectfactoryimpl, hibernateexception, hibernateexception, injectservice, jdbc, override, sql, string, unable, unable, util

The Hibernate DialectFactoryImpl.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.service.jdbc.dialect.internal;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Map;

import org.hibernate.HibernateException;
import org.hibernate.cfg.AvailableSettings;
import org.hibernate.dialect.Dialect;
import org.hibernate.service.classloading.spi.ClassLoaderService;
import org.hibernate.service.classloading.spi.ClassLoadingException;
import org.hibernate.service.jdbc.dialect.spi.DialectFactory;
import org.hibernate.service.jdbc.dialect.spi.DialectResolver;
import org.hibernate.service.spi.InjectService;

/**
 * Standard implementation of the {@link DialectFactory} service.
 *
 * @author Steve Ebersole
 */
public class DialectFactoryImpl implements DialectFactory {
	private ClassLoaderService classLoaderService;

	@InjectService
	public void setClassLoaderService(ClassLoaderService classLoaderService) {
		this.classLoaderService = classLoaderService;
	}

	private DialectResolver dialectResolver;

	@InjectService
	public void setDialectResolver(DialectResolver dialectResolver) {
		this.dialectResolver = dialectResolver;
	}

	@Override
	public Dialect buildDialect(Map configValues, Connection connection) throws HibernateException {
		final String dialectName = (String) configValues.get( AvailableSettings.DIALECT );
		if ( dialectName != null ) {
			return constructDialect( dialectName );
		}
		else {
			return determineDialect( connection );
		}
	}

	private Dialect constructDialect(String dialectName) {
		try {
			return ( Dialect ) classLoaderService.classForName( dialectName ).newInstance();
		}
		catch ( ClassLoadingException e ) {
			throw new HibernateException( "Dialect class not found: " + dialectName, e );
		}
		catch ( HibernateException e ) {
			throw e;
		}
		catch ( Exception e ) {
			throw new HibernateException( "Could not instantiate dialect class", e );
		}
	}

	/**
	 * Determine the appropriate Dialect to use given the connection.
	 *
	 * @param connection The configured connection.
	 * @return The appropriate dialect instance.
	 *
	 * @throws HibernateException No connection given or no resolver could make
	 * the determination from the given connection.
	 */
	private Dialect determineDialect(Connection connection) {
		if ( connection == null ) {
			throw new HibernateException( "Connection cannot be null when 'hibernate.dialect' not set" );
		}

		try {
			final DatabaseMetaData databaseMetaData = connection.getMetaData();
			final Dialect dialect = dialectResolver.resolveDialect( databaseMetaData );

			if ( dialect == null ) {
				throw new HibernateException(
						"Unable to determine Dialect to use [name=" + databaseMetaData.getDatabaseProductName() +
								", majorVersion=" + databaseMetaData.getDatabaseMajorVersion() +
								"]; user must register resolver or explicitly set 'hibernate.dialect'"
				);
			}

			return dialect;
		}
		catch ( SQLException sqlException ) {
			throw new HibernateException(
					"Unable to access java.sql.DatabaseMetaData to determine appropriate Dialect to use",
					sqlException
			);
		}
	}
}