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/*-------------------------------------------------------------------------
*
* Copyright (c) 2003-2008, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgjdbc/org/postgresql/largeobject/BlobOutputStream.java,v 1.13 2008/01/08 06:56:30 jurka Exp $
*
*-------------------------------------------------------------------------
*/
package org.postgresql.largeobject;
import java.io.IOException;
import java.io.OutputStream;
import java.sql.SQLException;
/**
* This implements a basic output stream that writes to a LargeObject
*/
public class BlobOutputStream extends OutputStream
{
/**
* The parent LargeObject
*/
private LargeObject lo;
/**
* Buffer
*/
private byte buf[];
/**
* Size of the buffer (default 1K)
*/
private int bsize;
/**
* Position within the buffer
*/
private int bpos;
/**
* Create an OutputStream to a large object
* @param lo LargeObject
*/
public BlobOutputStream(LargeObject lo)
{
this(lo, 1024);
}
/**
* Create an OutputStream to a large object
* @param lo LargeObject
* @param bsize The size of the buffer used to improve performance
*/
public BlobOutputStream(LargeObject lo, int bsize)
{
this.lo = lo;
this.bsize = bsize;
buf = new byte[bsize];
bpos = 0;
}
public void write(int b) throws java.io.IOException
{
checkClosed();
try
{
if (bpos >= bsize)
{
lo.write(buf);
bpos = 0;
}
buf[bpos++] = (byte)b;
}
catch (SQLException se)
{
throw new IOException(se.toString());
}
}
public void write(byte[] buf, int off, int len) throws java.io.IOException
{
checkClosed();
try
{
// If we have any internally buffered data, send it first
if ( bpos > 0 )
flush();
if ( off == 0 && len == buf.length )
lo.write(buf); // save a buffer creation and copy since full buffer written
else
lo.write(buf, off, len);
}
catch (SQLException se)
{
throw new IOException(se.toString());
}
}
/**
* Flushes this output stream and forces any buffered output bytes
* to be written out. The general contract of <code>flush</code> is
* that calling it is an indication that, if any bytes previously
* written have been buffered by the implementation of the output
* stream, such bytes should immediately be written to their
* intended destination.
*
* @exception IOException if an I/O error occurs.
*/
public void flush() throws IOException
{
checkClosed();
try
{
if (bpos > 0)
lo.write(buf, 0, bpos);
bpos = 0;
}
catch (SQLException se)
{
throw new IOException(se.toString());
}
}
/**
* Closes this output stream and releases any system resources
* associated with this stream. The general contract of <code>close</code>
* is that it closes the output stream. A closed stream cannot perform
* output operations and cannot be reopened.
* <p>
* The <code>close</code> method of <code>OutputStream</code> does nothing.
*
* @exception IOException if an I/O error occurs.
*/
public void close() throws IOException
{
if (lo != null) {
try
{
flush();
lo.close();
lo = null;
}
catch (SQLException se)
{
throw new IOException(se.toString());
}
}
}
private void checkClosed() throws IOException
{
if (lo == null)
throw new IOException("BlobOutputStream is closed");
}
}
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