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Spring Framework example source code file (BlobSerializableType.java)

This example Spring Framework source code file (BlobSerializableType.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

blob, blobserializabletype, bytearrayoutputstream, bytearrayoutputstream, classnotfoundexception, couldn't, hibernateexception, hibernateexception, io, ioexception, jdbc, object, object, objectinputstream, objectinputstream, objectoutputstream, sql, transaction

The Spring Framework BlobSerializableType.java source code

/*
 * 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.hibernate3.support;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import javax.transaction.TransactionManager;

import org.hibernate.HibernateException;

import org.springframework.jdbc.support.lob.LobCreator;
import org.springframework.jdbc.support.lob.LobHandler;

/**
 * Hibernate UserType implementation for arbitrary objects that get serialized to BLOBs.
 * Retrieves the LobHandler to use from LocalSessionFactoryBean at config time.
 *
 * <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
 * @see org.springframework.orm.hibernate3.LocalSessionFactoryBean#setLobHandler
 */
public class BlobSerializableType extends AbstractLobType {

	/**
	 * Initial size for ByteArrayOutputStreams used for serialization output.
	 * <p>If a serialized object is larger than these 1024 bytes, the size of
	 * the byte array used by the output stream will be doubled each time the
	 * limit is reached.
	 */
	private static final int OUTPUT_BYTE_ARRAY_INITIAL_SIZE = 1024;

	/**
	 * 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 BlobSerializableType() {
		super();
	}

	/**
	 * Constructor used for testing: takes an explicit LobHandler
	 * and an explicit JTA TransactionManager (can be <code>null).
	 */
	protected BlobSerializableType(LobHandler lobHandler, TransactionManager jtaTransactionManager) {
		super(lobHandler, jtaTransactionManager);
	}

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

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

	public boolean isMutable() {
		return true;
	}

	public Object deepCopy(Object value) throws HibernateException {
		try {
			// Write to new byte array to clone.
			ByteArrayOutputStream baos = new ByteArrayOutputStream(OUTPUT_BYTE_ARRAY_INITIAL_SIZE);
			ObjectOutputStream oos = new ObjectOutputStream(baos);
			try {
				oos.writeObject(value);
			}
			finally {
				oos.close();
			}

			// Read it back and return a true copy.
			ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
			ObjectInputStream ois = new ObjectInputStream(bais);
			try {
				return ois.readObject();
			}
			finally {
				ois.close();
			}
		}
		catch (ClassNotFoundException ex) {
			throw new HibernateException("Couldn't clone BLOB contents", ex);
		}
		catch (IOException ex) {
			throw new HibernateException("Couldn't clone BLOB contents", ex);
		}
	}

	protected Object nullSafeGetInternal(
			ResultSet rs, String[] names, Object owner, LobHandler lobHandler)
			throws SQLException, IOException, HibernateException {

		InputStream is = lobHandler.getBlobAsBinaryStream(rs, names[0]);
		if (is != null) {
			ObjectInputStream ois = new ObjectInputStream(is);
			try {
				return ois.readObject();
			}
			catch (ClassNotFoundException ex) {
				throw new HibernateException("Could not deserialize BLOB contents", ex);
			}
			finally {
				ois.close();
			}
		}
		else {
			return null;
		}
	}

	protected void nullSafeSetInternal(
			PreparedStatement ps, int index, Object value, LobCreator lobCreator)
			throws SQLException, IOException {

		if (value != null) {
			ByteArrayOutputStream baos = new ByteArrayOutputStream(OUTPUT_BYTE_ARRAY_INITIAL_SIZE);
			ObjectOutputStream oos = new ObjectOutputStream(baos);
			try {
				oos.writeObject(value);
				oos.flush();
				lobCreator.setBlobAsBytes(ps, index, baos.toByteArray());
			}
			finally {
				oos.close();
			}
		}
		else {
			lobCreator.setBlobAsBytes(ps, index, null);
		}
	}

}

Other Spring Framework examples (source code examples)

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