001: /*
002: * $Header: /export/home/cvsroot/MyPersonalizerRepository/MyPersonalizer/Subsystems/Kernel/Sources/es/udc/mypersonalizer/kernel/model/repository/sql/storers/BasicAutoIncrementEntityIdentifierGeneratorSingleton.java,v 1.1.1.1 2004/03/25 12:08:36 fbellas Exp $
003: * $Revision: 1.1.1.1 $
004: * $Date: 2004/03/25 12:08:36 $
005: *
006: * =============================================================================
007: *
008: * Copyright (c) 2003, The MyPersonalizer Development Group
009: * (http://www.tic.udc.es/~fbellas/mypersonalizer/index.html) at
010: * University Of A Coruna
011: * All rights reserved.
012: *
013: * Redistribution and use in source and binary forms, with or without
014: * modification, are permitted provided that the following conditions are met:
015: *
016: * - Redistributions of source code must retain the above copyright notice,
017: * this list of conditions and the following disclaimer.
018: *
019: * - Redistributions in binary form must reproduce the above copyright notice,
020: * this list of conditions and the following disclaimer in the documentation
021: * and/or other materials provided with the distribution.
022: *
023: * - Neither the name of the University Of A Coruna nor the names of its
024: * contributors may be used to endorse or promote products derived from
025: * this software without specific prior written permission.
026: *
027: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
028: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
029: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
030: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
031: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
032: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
033: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
034: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
035: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
036: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
037: * POSSIBILITY OF SUCH DAMAGE.
038: *
039: */
040:
041: package es.udc.mypersonalizer.kernel.model.repository.sql.storers;
042:
043: import java.sql.Connection;
044: import java.sql.ResultSet;
045: import java.sql.SQLException;
046: import java.sql.Statement;
047:
048: import es.udc.mypersonalizer.kernel.model.repository.sql.config.DatabaseConventionsConfigManager;
049: import es.udc.mypersonalizer.kernel.model.repository.sql.config.DatabaseSpecificsConfigManager;
050: import es.udc.mypersonalizer.kernel.model.repository.sql.config.DatabaseTemplatesConfig;
051: import es.udc.mypersonalizer.kernel.model.repository.sql.util.SQLOperations;
052: import es.udc.mypersonalizer.kernel.util.exceptions.InternalErrorException;
053:
054: /**
055: * Identifier generator for databases that provide auto-increment columns.
056: * <p>
057: * This generator works by creating a new row on the emulated sequence
058: * (i.e. a table with just one column: an auto-increment column) and retrieving
059: * the generated value.
060: * <p>
061: * It uses
062: * {@link es.udc.mypersonalizer.kernel.model.repository.sql.config.DatabaseTemplatesConfig#getInsertId(String)}
063: * to obtain the query to insert the row and
064: * {@link es.udc.mypersonalizer.kernel.model.repository.sql.config.DatabaseTemplatesConfig#getNextId(String)}
065: * to obtain the query to retrieve the generated identifier.
066: *
067: * @author Abel Muinho
068: * @author Fernando Bellas
069: * @since 1.0
070: */
071: public class BasicAutoIncrementEntityIdentifierGeneratorSingleton
072: extends EntityIdentifierGeneratorSingleton {
073:
074: private String sequenceSuffix;
075: private DatabaseTemplatesConfig databaseTemplates;
076:
077: public BasicAutoIncrementEntityIdentifierGeneratorSingleton()
078: throws InternalErrorException {
079: super ();
080: sequenceSuffix = DatabaseConventionsConfigManager.getConfig()
081: .getSequenceSuffix();
082: databaseTemplates = DatabaseSpecificsConfigManager.getConfig()
083: .getDatabaseTemplatesConfig();
084: }
085:
086: public Long nextIdentifier(Connection connection,
087: String entityTableName) throws InternalErrorException {
088:
089: Statement statement = null;
090: ResultSet resultSet = null;
091:
092: try {
093:
094: String sequenceName = entityTableName + sequenceSuffix;
095: String insertString = databaseTemplates
096: .getInsertId(sequenceName);
097: String queryString = databaseTemplates
098: .getNextId(sequenceName);
099:
100: /* Insert an empty row to generate a new identifier. */
101: statement = connection.createStatement();
102:
103: /* Get generated identifier. */
104: statement.executeUpdate(insertString);
105: statement = connection.createStatement();
106: resultSet = statement.executeQuery(queryString);
107:
108: /* Get and return the generated identifier. */
109: if (!resultSet.next()) {
110: throw new InternalErrorException(
111: "There is no sequence for " + entityTableName);
112: }
113:
114: Long generatedKey = new Long(resultSet.getLong(1));
115:
116: return generatedKey;
117:
118: } catch (SQLException e) {
119: throw new InternalErrorException(e);
120: } finally {
121: SQLOperations.closeResultSet(resultSet);
122: SQLOperations.closeStatement(statement);
123: }
124: }
125:
126: }
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