/*
* Copyright 2002-2008 the original author or authors.
*
* 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.springframework.jdbc.support.incrementer;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.sql.DataSource;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.jdbc.datasource.DataSourceUtils;
import org.springframework.jdbc.support.JdbcUtils;
/**
* Abstract base class for {@link DataFieldMaxValueIncrementer} implementations that use
* a database sequence. Subclasses need to provide the database-specific SQL to use.
*
* @author Juergen Hoeller
* @since 26.02.2004
* @see #getSequenceQuery
*/
public abstract class AbstractSequenceMaxValueIncrementer extends AbstractDataFieldMaxValueIncrementer {
/**
* Default constructor for bean property style usage.
* @see #setDataSource
* @see #setIncrementerName
*/
public AbstractSequenceMaxValueIncrementer() {
}
/**
* Convenience constructor.
* @param dataSource the DataSource to use
* @param incrementerName the name of the sequence/table to use
*/
public AbstractSequenceMaxValueIncrementer(DataSource dataSource, String incrementerName) {
super(dataSource, incrementerName);
}
/**
* Executes the SQL as specified by {@link #getSequenceQuery()}.
*/
@Override
protected long getNextKey() throws DataAccessException {
Connection con = DataSourceUtils.getConnection(getDataSource());
Statement stmt = null;
ResultSet rs = null;
try {
stmt = con.createStatement();
DataSourceUtils.applyTransactionTimeout(stmt, getDataSource());
rs = stmt.executeQuery(getSequenceQuery());
if (rs.next()) {
return rs.getLong(1);
}
else {
throw new DataAccessResourceFailureException("Sequence query did not return a result");
}
}
catch (SQLException ex) {
throw new DataAccessResourceFailureException("Could not obtain sequence value", ex);
}
finally {
JdbcUtils.closeResultSet(rs);
JdbcUtils.closeStatement(stmt);
DataSourceUtils.releaseConnection(con, getDataSource());
}
}
/**
* Return the database-specific query to use for retrieving a sequence value.
* <p>The provided SQL is supposed to result in a single row with a single
* column that allows for extracting a <code>long</code> value.
*/
protected abstract String getSequenceQuery();
}
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