/*
 * Copyright (c) JForum Team
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, 
 * with or without modification, are permitted provided 
 * that the following conditions are met:
 * 
 * 1) Redistributions of source code must retain the above 
 * copyright notice, this list of conditions and the 
 * following  disclaimer.
 * 2)  Redistributions in binary form must reproduce the 
 * above copyright notice, this list of conditions and 
 * the following disclaimer in the documentation and/or 
 * other materials provided with the distribution.
 * 3) Neither the name of "Rafael Steil" nor 
 * the names of its contributors may be used to endorse 
 * or promote products derived from this software without 
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT 
 * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY 
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
 * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
 * IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
 * 
 * Created on Jan 26, 2005 4:42:44 PM
 * The JForum Project
 * http://www.jforum.net
 */
package net.jforum.dao.oracle;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import net.jforum.JForumExecutionContext;
import net.jforum.exceptions.DatabaseException;
import net.jforum.util.DbUtils;
import oracle.sql.BLOB;

/**
 * @author Dmitriy Kiriy
 * @version $Id: OracleUtils.java,v 1.14 2007/08/31 22:56:40 rafaelsteil Exp $
 */
public class OracleUtils
{
	public static String readBlobUTF16BinaryStream(ResultSet rs, String fieldName) throws SQLException
	{
		try {
			Blob clob = rs.getBlob(fieldName);

			InputStream is = clob.getBinaryStream();
			StringBuffer sb = new StringBuffer();
			
			int readedBytes;
			int bufferSize = 4096;
			
			do {
				byte[] bytes = new byte[bufferSize];
				
				readedBytes = is.read(bytes);
				
				if (readedBytes > 0) {
					String readed = new String(bytes, 0, readedBytes, "UTF-16");
					sb.append(readed);
				}
			} while (readedBytes == bufferSize);

			is.close();
			return sb.toString();
		}
		catch (IOException e) {
			throw new DatabaseException(e);
		}
	}

	/**
	 * The query should look like:
	 * 
	 * SELECT blob_field from any_table WHERE id = ? FOR UPDATE
	 * 
	 * BUT KEEP IN MIND:
	 * 
	 * When you insert record in previous step, it should go with empty_blob() like:
	 * 
	 * INSERT INTO jforum_posts_text ( post_text ) VALUES (EMPTY_BLOB())
	 * 
	 * @param query String
	 * @param idForQuery int
	 * @param value String
	 * @throws SQLException
	 */
	public static void writeBlobUTF16BinaryStream(String query, int idForQuery, String value) throws Exception
	{
		PreparedStatement p = null;
		ResultSet rs = null;
		OutputStream blobWriter = null;
		
		try {
			p = JForumExecutionContext.getConnection().prepareStatement(query);
			p.setInt(1, idForQuery);

			rs = p.executeQuery();
			rs.next();
			Blob text = rs.getBlob(1);

			if (text instanceof BLOB) {
				blobWriter = ((BLOB) text).getBinaryOutputStream();
			}
			else {
				blobWriter = text.setBinaryStream(0);
			}

			blobWriter.write(value.getBytes("UTF-16"));

			blobWriter.close();
		}
		catch (IOException e) {
			throw new DatabaseException(e);
		}
		finally {
			if (blobWriter != null) {
				blobWriter.close();
			}
			
			DbUtils.close(rs, p);
		}
	}
}