Hibernate example source code file (TableStructure.java)

This example Hibernate source code file (TableStructure.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, class, hibernateexception, integraldatatypeholder, integraldatatypeholder, jdbc, override, override, preparedstatement, sql, sqlexception, sqlexception, string, string, stringbuffer, tablestructure

The Hibernate TableStructure.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008-2011, 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.enhanced;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import org.hibernate.HibernateException;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.LockMode;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.engine.jdbc.internal.FormatStyle;
import org.hibernate.engine.jdbc.spi.JdbcServices;
import org.hibernate.engine.jdbc.spi.SqlStatementLogger;
import org.hibernate.id.IdentifierGenerationException;
import org.hibernate.id.IdentifierGeneratorHelper;
import org.hibernate.id.IntegralDataTypeHolder;
import org.hibernate.jdbc.AbstractReturningWork;

import org.jboss.logging.Logger;

/**
 * Describes a table used to mimic sequence behavior
 *
 * @author Steve Ebersole
 */
public class TableStructure implements DatabaseStructure {

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

	private final String tableName;
	private final String valueColumnName;
	private final int initialValue;
	private final int incrementSize;
	private final Class numberType;
	private final String selectQuery;
	private final String updateQuery;

	private boolean applyIncrementSizeToSourceValues;
	private int accessCounter;

	public TableStructure(
			Dialect dialect,
			String tableName,
			String valueColumnName,
			int initialValue,
			int incrementSize,
			Class numberType) {
		this.tableName = tableName;
		this.initialValue = initialValue;
		this.incrementSize = incrementSize;
		this.valueColumnName = valueColumnName;
		this.numberType = numberType;

		selectQuery = "select " + valueColumnName + " as id_val" +
				" from " + dialect.appendLockHint( LockMode.PESSIMISTIC_WRITE, tableName ) +
				dialect.getForUpdateString();

		updateQuery = "update " + tableName +
				" set " + valueColumnName + "= ?" +
				" where " + valueColumnName + "=?";
	}

	@Override
	public String getName() {
		return tableName;
	}

	@Override
	public int getInitialValue() {
		return initialValue;
	}

	@Override
	public int getIncrementSize() {
		return incrementSize;
	}

	@Override
	public int getTimesAccessed() {
		return accessCounter;
	}

	@Override
	public void prepare(Optimizer optimizer) {
		applyIncrementSizeToSourceValues = optimizer.applyIncrementSizeToSourceValues();
	}

	@Override
	public AccessCallback buildCallback(final SessionImplementor session) {
		return new AccessCallback() {
			@Override
			public IntegralDataTypeHolder getNextValue() {
				return session.getTransactionCoordinator().getTransaction().createIsolationDelegate().delegateWork(
						new AbstractReturningWork<IntegralDataTypeHolder>() {
							@Override
							public IntegralDataTypeHolder execute(Connection connection) throws SQLException {
								final SqlStatementLogger statementLogger = session
										.getFactory()
										.getServiceRegistry()
										.getService( JdbcServices.class )
										.getSqlStatementLogger();
								IntegralDataTypeHolder value = IdentifierGeneratorHelper.getIntegralDataTypeHolder( numberType );
								int rows;
								do {
									statementLogger.logStatement( selectQuery, FormatStyle.BASIC.getFormatter() );
									PreparedStatement selectStatement = connection.prepareStatement( selectQuery );
									try {
										ResultSet selectRS = selectStatement.executeQuery();
										if ( !selectRS.next() ) {
											String err = "could not read a hi value - you need to populate the table: " + tableName;
											LOG.error( err );
											throw new IdentifierGenerationException( err );
										}
										value.initialize( selectRS, 1 );
										selectRS.close();
									}
									catch ( SQLException sqle ) {
										LOG.error( "could not read a hi value", sqle );
										throw sqle;
									}
									finally {
										selectStatement.close();
									}

									statementLogger.logStatement( updateQuery, FormatStyle.BASIC.getFormatter() );
									PreparedStatement updatePS = connection.prepareStatement( updateQuery );
									try {
										final int increment = applyIncrementSizeToSourceValues ? incrementSize : 1;
										final IntegralDataTypeHolder updateValue = value.copy().add( increment );
										updateValue.bind( updatePS, 1 );
										value.bind( updatePS, 2 );
										rows = updatePS.executeUpdate();
									}
									catch ( SQLException e ) {
									    LOG.unableToUpdateQueryHiValue(tableName, e);
										throw e;
									}
									finally {
										updatePS.close();
									}
								} while ( rows == 0 );

								accessCounter++;

								return value;
							}
						},
						true
				);
			}
		};
	}

	@Override
	public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
		return new String[] {
				dialect.getCreateTableString() + " " + tableName + " ( " + valueColumnName + " " + dialect.getTypeName( Types.BIGINT ) + " )",
				"insert into " + tableName + " values ( " + initialValue + " )"
		};
	}

	@Override
	public String[] sqlDropStrings(Dialect dialect) throws HibernateException {
		StringBuffer sqlDropString = new StringBuffer().append( "drop table " );
		if ( dialect.supportsIfExistsBeforeTableName() ) {
			sqlDropString.append( "if exists " );
		}
		sqlDropString.append( tableName ).append( dialect.getCascadeConstraintsString() );
		if ( dialect.supportsIfExistsAfterTableName() ) {
			sqlDropString.append( " if exists" );
		}
		return new String[] { sqlDropString.toString() };
	}
}