/*
* Copyright 2009 Ahmad Hassan, Ralf Joachim
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.castor.cpa.persistence.sql.keygen;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.text.MessageFormat;
import java.util.Properties;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.exolab.castor.jdo.PersistenceException;
import org.castor.core.util.Messages;
import org.castor.cpa.persistence.sql.keygen.typehandler.KeyGeneratorTypeHandler;
import org.castor.cpa.persistence.sql.keygen.typehandler.KeyGeneratorTypeHandlerBigDecimal;
import org.castor.cpa.persistence.sql.keygen.typehandler.KeyGeneratorTypeHandlerInteger;
import org.castor.cpa.persistence.sql.keygen.typehandler.KeyGeneratorTypeHandlerLong;
import org.castor.cpa.persistence.sql.keygen.typehandler.KeyGeneratorTypeHandlerString;
import org.exolab.castor.mapping.MappingException;
import org.exolab.castor.persist.spi.PersistenceFactory;
/**
* Extends AbstractAfterKeyGenerator and implements additional methods specific
* to Sequence Key generator. It invovles the fetching the Table ID after the
* record is inserted into the table.
*
* @author <a href="mailto:ahmad DOT hassan AT gmail DOT com">Ahmad Hassan</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision$ $Date: 2009-07-13 17:22:43 (Tue, 28 Jul 2009) $
*/
public final class SequenceAfterKeyGenerator extends AbstractAfterKeyGenerator {
//-----------------------------------------------------------------------------------
/** The <a href="http://jakarta.apache.org/commons/logging/">Jakarta
* Commons Logging</a> instance used for all logging. */
private static final Log LOG = LogFactory.getLog(SequenceAfterKeyGenerator.class);
/** Key length used for KeyGeneratorTypeHandlerString. */
private static final int STRING_KEY_LENGTH = 8;
/** Persistence factory for the database engine the entity is persisted in.
* Used to format the SQL statement. */
private PersistenceFactory _factory;
/** Sequence name associated with the table. */
private String _seqName;
/** Particular type handler instance. */
private KeyGeneratorTypeHandler<? extends Object> _typeHandler;
//-----------------------------------------------------------------------------------
/**
* Initialize the SEQUENCE key generator for AFTER_INSERT style
* {@link #generateKey} is called after INSERT.
*
* @param factory A PersistenceFactory instance.
* @param params Database engine specific parameters.
* @param sqlType A SQLTypidentifier.
* @throws MappingException if this key generator is not compatible with the
* persistance factory.
*/
public SequenceAfterKeyGenerator(final PersistenceFactory factory, final Properties params,
final int sqlType) throws MappingException {
super(params);
_factory = factory;
_seqName = params.getProperty("sequence", "{0}_seq");
initSqlTypeHandler(sqlType);
}
/**
* Initialize the Handler based on SQL Type.
*
* @param sqlType A SQLTypidentifier.
*/
protected void initSqlTypeHandler(final int sqlType) {
if (sqlType == Types.INTEGER) {
_typeHandler = new KeyGeneratorTypeHandlerInteger(true);
} else if (sqlType == Types.BIGINT) {
_typeHandler = new KeyGeneratorTypeHandlerLong(true);
} else if ((sqlType == Types.CHAR) || (sqlType == Types.VARCHAR)) {
_typeHandler = new KeyGeneratorTypeHandlerString(true, STRING_KEY_LENGTH);
} else {
_typeHandler = new KeyGeneratorTypeHandlerBigDecimal(true);
}
}
/**
* Formats the sequence name using name of the table and ID.
*
* @param tableName Name of the table.
* @param primKeyName ID of the table.
* @return Strign representing formatted sequence name.
*/
private String getSeqName(final String tableName, final String primKeyName) {
return MessageFormat.format(_seqName, new Object[] {tableName, primKeyName});
}
//-----------------------------------------------------------------------------------
/**
* @param conn An open connection within the given transaction.
* @param tableName The table name.
* @param primKeyName The primary key name.
* @return A new key.
* @throws PersistenceException An error occured talking to persistent storage.
*/
public Object generateKey(final Connection conn, final String tableName,
final String primKeyName) throws PersistenceException {
PreparedStatement stmt = null;
ResultSet rs = null;
try {
// prepares the statement
String sql = _factory.getSequenceAfterSelectString(
getSeqName(tableName, primKeyName), tableName);
stmt = conn.prepareStatement(sql);
// execute the prepared statement
rs = stmt.executeQuery();
// process result set using appropriate handler and return its value
return _typeHandler.getValue(rs);
} catch (SQLException e) {
String msg = Messages.format("persist.keyGenSQL",
this.getClass().getName(), e.toString());
throw new PersistenceException(msg);
} finally {
try {
if (rs != null) { rs.close(); }
if (stmt != null) { stmt.close(); }
} catch (SQLException e) {
LOG.warn("Problem closing JDBC statement", e);
}
}
}
/**
* {@inheritDoc}
*/
public boolean isInSameConnection() {
return true;
}
//-----------------------------------------------------------------------------------
}