/*
* Copyright 2002-2006 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.hibernate3.support;
import java.io.UnsupportedEncodingException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import javax.transaction.TransactionManager;
import org.springframework.jdbc.support.lob.LobCreator;
import org.springframework.jdbc.support.lob.LobHandler;
/**
* Hibernate UserType implementation for Strings that get mapped to BLOBs.
* Retrieves the LobHandler to use from LocalSessionFactoryBean at config time.
*
* <p>This is intended for the (arguably unnatural, but still common) case
* where character data is stored in a binary LOB. This requires encoding
* and decoding the characters within this UserType; see the javadoc of the
* <code>getCharacterEncoding()</code> method.
*
* <p>Can also be defined in generic Hibernate mappings, as DefaultLobCreator will
* work with most JDBC-compliant database drivers. In this case, the field type
* does not have to be BLOB: For databases like MySQL and MS SQL Server, any
* large enough binary type will work.
*
* @author Juergen Hoeller
* @since 1.2.7
* @see #getCharacterEncoding()
* @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#setLobHandler
*/
public class BlobStringType extends AbstractLobType {
/**
* Constructor used by Hibernate: fetches config-time LobHandler and
* config-time JTA TransactionManager from LocalSessionFactoryBean.
* @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#getConfigTimeLobHandler
* @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#getConfigTimeTransactionManager
*/
public BlobStringType() {
super();
}
/**
* Constructor used for testing: takes an explicit LobHandler
* and an explicit JTA TransactionManager (can be <code>null</code>).
*/
protected BlobStringType(LobHandler lobHandler, TransactionManager jtaTransactionManager) {
super(lobHandler, jtaTransactionManager);
}
public int[] sqlTypes() {
return new int[] {Types.BLOB};
}
public Class returnedClass() {
return String.class;
}
@Override
protected Object nullSafeGetInternal(
ResultSet rs, String[] names, Object owner, LobHandler lobHandler)
throws SQLException, UnsupportedEncodingException {
byte[] bytes = lobHandler.getBlobAsBytes(rs, names[0]);
if (bytes != null) {
String encoding = getCharacterEncoding();
return (encoding != null ? new String(bytes, encoding) : new String(bytes));
}
else {
return null;
}
}
@Override
protected void nullSafeSetInternal(
PreparedStatement ps, int index, Object value, LobCreator lobCreator)
throws SQLException, UnsupportedEncodingException {
if (value != null) {
String str = (String) value;
String encoding = getCharacterEncoding();
byte[] bytes = (encoding != null ? str.getBytes(encoding) : str.getBytes());
lobCreator.setBlobAsBytes(ps, index, bytes);
}
else {
lobCreator.setBlobAsBytes(ps, index, null);
}
}
/**
* Determine the character encoding to apply to the BLOB's bytes
* to turn them into a String.
* <p>Default is <code>null</code>, indicating to use the platform
* default encoding. To be overridden in subclasses for a specific
* encoding such as "ISO-8859-1" or "UTF-8".
* @return the character encoding to use, or <code>null</code>
* to use the platform default encoding
* @see java.lang.String#String(byte[], String)
* @see java.lang.String#getBytes(String)
*/
protected String getCharacterEncoding() {
return null;
}
}
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