Spring Framework example source code file (BlobStringType.java)

This example Spring Framework source code file (BlobStringType.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

abstractlobtype, blobstringtype, blobstringtype, io, jdbc, lobhandler, object, object, preparedstatement, resultset, sql, sqlexception, sqlexception, string, string, transaction, transactionmanager, unsupportedencodingexception

The Spring Framework BlobStringType.java source code

/*
 * 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() 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).
	 */
	protected BlobStringType(LobHandler lobHandler, TransactionManager jtaTransactionManager) {
		super(lobHandler, jtaTransactionManager);
	}

	public int[] sqlTypes() {
		return new int[] {Types.BLOB};
	}

	public Class returnedClass() {
		return String.class;
	}

	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;
		}
	}

	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 null, 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
	 * to use the platform default encoding
	 * @see java.lang.String#String(byte[], String)
	 * @see java.lang.String#getBytes(String)
	 */
	protected String getCharacterEncoding() {
		return null;
	}

}