/*
* Copyright 2002-2005 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.orm.ibatis.support;
import java.io.IOException;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.ibatis.sqlmap.engine.type.BaseTypeHandler;
import org.springframework.jdbc.datasource.DataSourceUtils;
import org.springframework.jdbc.support.lob.LobCreator;
import org.springframework.jdbc.support.lob.LobHandler;
import org.springframework.orm.ibatis.SqlMapClientFactoryBean;
import org.springframework.transaction.support.TransactionSynchronizationAdapter;
import org.springframework.transaction.support.TransactionSynchronizationManager;
/**
* Abstract base class for iBATIS TypeHandler implementations that map to LOBs.
* Retrieves the LobHandler to use from SqlMapClientFactoryBean at config time.
*
* <p>For writing LOBs, an active Spring transaction synchronization is required,
* to be able to register a synchronization that closes the LobCreator.
*
* <p>Offers template methods for setting parameters and getting result values,
* passing in the LobHandler or LobCreator to use.
*
* @author Juergen Hoeller
* @since 1.1.5
* @see org.springframework.jdbc.support.lob.LobHandler
* @see org.springframework.jdbc.support.lob.LobCreator
* @see org.springframework.orm.ibatis.SqlMapClientFactoryBean#setLobHandler
*/
public abstract class AbstractLobTypeHandler extends BaseTypeHandler {
/**
* Order value for TransactionSynchronization objects that clean up LobCreators.
* Return DataSourceUtils.#CONNECTION_SYNCHRONIZATION_ORDER - 100 to execute
* LobCreator cleanup before JDBC Connection cleanup, if any.
* @see org.springframework.jdbc.datasource.DataSourceUtils#CONNECTION_SYNCHRONIZATION_ORDER
*/
public static final int LOB_CREATOR_SYNCHRONIZATION_ORDER =
DataSourceUtils.CONNECTION_SYNCHRONIZATION_ORDER - 200;
private LobHandler lobHandler;
/**
* Constructor used by iBATIS: fetches config-time LobHandler from
* SqlMapClientFactoryBean.
* @see org.springframework.orm.ibatis.SqlMapClientFactoryBean#getConfigTimeLobHandler
*/
public AbstractLobTypeHandler() {
this(SqlMapClientFactoryBean.getConfigTimeLobHandler());
}
/**
* Constructor used for testing: takes an explicit LobHandler.
*/
protected AbstractLobTypeHandler(LobHandler lobHandler) {
if (lobHandler == null) {
throw new IllegalStateException("No LobHandler found for configuration - " +
"lobHandler property must be set on SqlMapClientFactoryBean");
}
this.lobHandler = lobHandler;
}
/**
* This implementation delegates to setParameterInternal,
* passing in a transaction-synchronized LobCreator for the
* LobHandler of this type.
* @see #setParameterInternal
*/
public final void setParameter(PreparedStatement ps, int i, Object parameter, String jdbcType)
throws SQLException {
if (!TransactionSynchronizationManager.isSynchronizationActive()) {
throw new IllegalStateException("Spring transaction synchronization needs to be active for " +
"setting values in iBATIS TypeHandlers that delegate to a Spring LobHandler");
}
final LobCreator lobCreator = this.lobHandler.getLobCreator();
try {
setParameterInternal(ps, i, parameter, jdbcType, lobCreator);
}
catch (IOException ex) {
throw new SQLException("I/O errors during LOB access: " + ex.getMessage());
}
TransactionSynchronizationManager.registerSynchronization(
new LobCreatorSynchronization(lobCreator));
}
/**
* This implementation delegates to the getResult version
* that takes a column index.
* @see #getResult(java.sql.ResultSet, String)
* @see java.sql.ResultSet#findColumn
*/
public final Object getResult(ResultSet rs, String columnName) throws SQLException {
return getResult(rs, rs.findColumn(columnName));
}
/**
* This implementation delegates to getResultInternal,
* passing in the LobHandler of this type.
* @see #getResultInternal
*/
public final Object getResult(ResultSet rs, int columnIndex) throws SQLException {
try {
return getResultInternal(rs, columnIndex, this.lobHandler);
}
catch (IOException ex) {
throw new SQLException(
"I/O errors during LOB access: " + ex.getClass().getName() + ": " + ex.getMessage());
}
}
/**
* This implementation always throws a SQLException:
* retrieving LOBs from a CallableStatement is not supported.
*/
public Object getResult(CallableStatement cs, int columnIndex) throws SQLException {
throw new SQLException("Retrieving LOBs from a CallableStatement is not supported");
}
/**
* Template method to set the given value on the given statement.
* @param ps the PreparedStatement to set on
* @param index the statement parameter index
* @param value the parameter value to set
* @param jdbcType the JDBC type of the parameter
* @param lobCreator the LobCreator to use
* @throws SQLException if thrown by JDBC methods
* @throws IOException if thrown by streaming methods
*/
protected abstract void setParameterInternal(
PreparedStatement ps, int index, Object value, String jdbcType, LobCreator lobCreator)
throws SQLException, IOException;
/**
* Template method to extract a value from the given result set.
* @param rs the ResultSet to extract from
* @param index the index in the ResultSet
* @param lobHandler the LobHandler to use
* @return the extracted value
* @throws SQLException if thrown by JDBC methods
* @throws IOException if thrown by streaming methods
*/
protected abstract Object getResultInternal(ResultSet rs, int index, LobHandler lobHandler)
throws SQLException, IOException;
/**
* Callback for resource cleanup at the end of a Spring transaction.
* Invokes LobCreator.close to clean up temporary LOBs that might have been created.
* @see org.springframework.jdbc.support.lob.LobCreator#close
*/
private static class LobCreatorSynchronization extends TransactionSynchronizationAdapter {
private final LobCreator lobCreator;
public LobCreatorSynchronization(LobCreator lobCreator) {
this.lobCreator = lobCreator;
}
@Override
public int getOrder() {
return LOB_CREATOR_SYNCHRONIZATION_ORDER;
}
@Override
public void beforeCompletion() {
this.lobCreator.close();
}
}
}
|