Hibernate example source code file (SequenceGenerator.java)

This example Hibernate source code file (SequenceGenerator.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

hibernateexception, integraldatatypeholder, integraldatatypeholder, io, jdbc, mappingexception, object, object, objectnamenormalizer, parameters, persistentidentifiergenerator, sequence, sequence, sql, string, string, type, util

The Hibernate SequenceGenerator.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.id;
import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
import org.hibernate.HibernateException;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.MappingException;
import org.hibernate.cfg.ObjectNameNormalizer;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.internal.util.config.ConfigurationHelper;
import org.hibernate.mapping.Table;
import org.hibernate.type.Type;
import org.jboss.logging.Logger;

/**
 * <b>sequence

 * <br>
 * Generates <tt>long values using an oracle-style sequence. A higher
 * performance algorithm is <tt>SequenceHiLoGenerator.

 * <br>
 * Mapping parameters supported: sequence, parameters.
 *
 * @see SequenceHiLoGenerator
 * @see TableHiLoGenerator
 * @author Gavin King
 */
public class SequenceGenerator implements PersistentIdentifierGenerator, Configurable {

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

	/**
	 * The sequence parameter
	 */
	public static final String SEQUENCE = "sequence";

	/**
	 * The parameters parameter, appended to the create sequence DDL.
	 * For example (Oracle): <tt>INCREMENT BY 1 START WITH 1 MAXVALUE 100 NOCACHE.
	 */
	public static final String PARAMETERS = "parameters";

	private String sequenceName;
	private String parameters;
	private Type identifierType;
	private String sql;

	protected Type getIdentifierType() {
		return identifierType;
	}

	public void configure(Type type, Properties params, Dialect dialect) throws MappingException {
		ObjectNameNormalizer normalizer = ( ObjectNameNormalizer ) params.get( IDENTIFIER_NORMALIZER );
		sequenceName = normalizer.normalizeIdentifierQuoting(
				ConfigurationHelper.getString( SEQUENCE, params, "hibernate_sequence" )
		);
		parameters = params.getProperty( PARAMETERS );

		if ( sequenceName.indexOf( '.' ) < 0 ) {
			final String schemaName = normalizer.normalizeIdentifierQuoting( params.getProperty( SCHEMA ) );
			final String catalogName = normalizer.normalizeIdentifierQuoting( params.getProperty( CATALOG ) );
			sequenceName = Table.qualify(
					dialect.quote( catalogName ),
					dialect.quote( schemaName ),
					dialect.quote( sequenceName )
			);
		}
		else {
			// if already qualified there is not much we can do in a portable manner so we pass it
			// through and assume the user has set up the name correctly.
		}

		this.identifierType = type;
		sql = dialect.getSequenceNextValString( sequenceName );
	}

	public Serializable generate(SessionImplementor session, Object obj) {
		return generateHolder( session ).makeValue();
	}

	protected IntegralDataTypeHolder generateHolder(SessionImplementor session) {
		try {
			PreparedStatement st = session.getTransactionCoordinator().getJdbcCoordinator().getStatementPreparer().prepareStatement( sql );
			try {
				ResultSet rs = st.executeQuery();
				try {
					rs.next();
					IntegralDataTypeHolder result = buildHolder();
					result.initialize( rs, 1 );
                    LOG.debugf("Sequence identifier generated: %s", result);
					return result;
				}
				finally {
					rs.close();
				}
			}
			finally {
				st.close();
			}

		}
		catch (SQLException sqle) {
			throw session.getFactory().getSQLExceptionHelper().convert(
					sqle,
					"could not get next sequence value",
					sql
			);
		}
	}

	protected IntegralDataTypeHolder buildHolder() {
		return IdentifierGeneratorHelper.getIntegralDataTypeHolder( identifierType.getReturnedClass() );
	}

	public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
		String[] ddl = dialect.getCreateSequenceStrings(sequenceName);
		if ( parameters != null ) {
			ddl[ddl.length - 1] += ' ' + parameters;
		}
		return ddl;
	}

	public String[] sqlDropStrings(Dialect dialect) throws HibernateException {
		return dialect.getDropSequenceStrings(sequenceName);
	}

	public Object generatorKey() {
		return sequenceName;
	}

	public String getSequenceName() {
		return sequenceName;
	}
}