Hibernate example source code file (SequenceStructure.java)

This example Hibernate source code file (SequenceStructure.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

accesscallback, accesscallback, class, coremessagelogger, dialect, hibernateexception, integraldatatypeholder, integraldatatypeholder, jdbc, log, sequencestructure, sequencestructure, sql, string, string, throwable

The Hibernate SequenceStructure.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
 *
 * 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.enhanced;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.hibernate.HibernateException;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.id.IdentifierGeneratorHelper;
import org.hibernate.id.IntegralDataTypeHolder;

import org.jboss.logging.Logger;

/**
 * Describes a sequence.
 *
 * @author Steve Ebersole
 */
public class SequenceStructure implements DatabaseStructure {

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

	private final String sequenceName;
	private final int initialValue;
	private final int incrementSize;
	private final Class numberType;
	private final String sql;
	private boolean applyIncrementSizeToSourceValues;
	private int accessCounter;

	public SequenceStructure(
			Dialect dialect,
			String sequenceName,
			int initialValue,
			int incrementSize,
			Class numberType) {
		this.sequenceName = sequenceName;
		this.initialValue = initialValue;
		this.incrementSize = incrementSize;
		this.numberType = numberType;
		sql = dialect.getSequenceNextValString( sequenceName );
	}

	/**
	 * {@inheritDoc}
	 */
	public String getName() {
		return sequenceName;
	}

	/**
	 * {@inheritDoc}
	 */
	public int getIncrementSize() {
		return incrementSize;
	}

	/**
	 * {@inheritDoc}
	 */
	public int getTimesAccessed() {
		return accessCounter;
	}

	/**
	 * {@inheritDoc}
	 */
	public int getInitialValue() {
		return initialValue;
	}

	/**
	 * {@inheritDoc}
	 */
	public AccessCallback buildCallback(final SessionImplementor session) {
		return new AccessCallback() {
			public IntegralDataTypeHolder getNextValue() {
				accessCounter++;
				try {
					PreparedStatement st = session.getTransactionCoordinator().getJdbcCoordinator().getStatementPreparer().prepareStatement( sql );
					try {
						ResultSet rs = st.executeQuery();
						try {
							rs.next();
							IntegralDataTypeHolder value = IdentifierGeneratorHelper.getIntegralDataTypeHolder( numberType );
							value.initialize( rs, 1 );
                            LOG.debugf("Sequence value obtained: %s", value.makeValue());
							return value;
						}
						finally {
							try {
								rs.close();
							}
							catch( Throwable ignore ) {
								// intentionally empty
							}
						}
					}
					finally {
						st.close();
					}

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

	/**
	 * {@inheritDoc}
	 */
	public void prepare(Optimizer optimizer) {
		applyIncrementSizeToSourceValues = optimizer.applyIncrementSizeToSourceValues();
	}

	/**
	 * {@inheritDoc}
	 */
	public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
		int sourceIncrementSize = applyIncrementSizeToSourceValues ? incrementSize : 1;
		return dialect.getCreateSequenceStrings( sequenceName, initialValue, sourceIncrementSize );
	}

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