OutputStreamWrapper.java
/*
** Module : OutputStreamWrapper.java
** Abstract : provides an external OutputStream wrapper for a P2J Stream
**
** Copyright (c) 2006-2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- --JPRM-- -----------------------------------Description-----------------------------------
** 001 GES 20060215 @24675 First version which provides an external OutputStream wrapper for a P2J Stream.
** 002 ECF 20171029 Made write(byte[], int, int) more efficient; implemented close to close
** underlying stream.
** 003 ME 20210322 Proxy flush to the underlying stream.
** TJD 20220608 Chunked write implementation
** OM 20221003 Allow the wrapper to be tenmporarily unclosable.
** CA 20221031 Javadoc fixes.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
** You may not represent yourself as Golden Code Development Corporation or FWD.
**
** You may not represent yourself for publicity purposes as associated with
** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
** You may not represent the covered work as solely your work. All modified
** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.util;
import java.io.*;
/**
* Provides an external <code>OutputStream</code> wrapper for a {@link Stream}.
*/
public class OutputStreamWrapper
extends OutputStream
{
/** The wrapped stream. */
private Stream out = null;
/** Flag which allow the wrapped stream to be closed. */
private boolean closable = true;
/**
* The chunk to write at once to the remote {@link #out stream}, via in the {@link #write(byte[], int, int)}
* implementation.
*/
private static final int WRITE_CHUNK_SIZE = 1024 * 1024; // 1MB
/**
* Creates an instance with the associated stream. The created wrapper is closable.
*/
public OutputStreamWrapper(Stream out)
{
this.out = out;
}
/**
* Creates an instance with the associated stream.
*
* @param closable
* Configures whether the wrapper is closable. The attribute can be reset to {@code true} using
* {@link #setClosable()} method.
*/
public OutputStreamWrapper(Stream out, boolean closable)
{
this.out = out;
this.closable = closable;
}
/**
* Writes the specified byte to this output stream (only the low order 8
* bits are written, the high order 24 bits are ignored).
*
* @param b
* The byte to write.
*
* @throws IOException
* if an I/O error occurs. In particular, an IOException may be
* thrown if the output stream has been closed.
*/
@Override
public void write(int b)
throws IOException
{
if (out == null)
{
throw new IOException("Stream is not open.");
}
out.writeByte((byte) (b & 0xFF));
}
/**
* Writes the entire contents of the specified byte array to this output
* stream.
*
* @param b
* The byte array to write.
*
* @throws IOException
* if an I/O error occurs. In particular, an IOException may be
* thrown if the output stream has been closed.
* @throws NullPointerException
* if the array is <code>null</code>.
*/
@Override
public void write(byte[] b)
throws IOException,
NullPointerException
{
if (out == null)
{
throw new IOException("Stream is not open.");
}
write(b, 0, b.length);
}
/**
* Writes <code>len</code> bytes from the specified byte array starting
* at offset <code>off</code> in this output stream. Element b[off] is
* the first byte written and b[off+len-1] is the last byte written.
*
* @param b
* The array of bytes to write.
* @param off
* the start offset in the array.
* @param len
* the number of bytes to write.
*
* @throws IOException
* if an I/O error occurs. In particular, an IOException may be
* thrown if the output stream has been closed.
* @throws NullPointerException
* if the array is <code>null</code>.
* @throws IndexOutOfBoundsException
* if the offset or length are negative, or if offset + length
* is larger than the length of the array.
*/
@Override
public void write(byte[] b, int off, int len)
throws IOException,
NullPointerException,
IndexOutOfBoundsException
{
if (out == null)
{
throw new IOException("Stream is not open.");
}
// Bounds check
if ((off + len) > b.length || off < 0 || len < 0)
{
throw new IndexOutOfBoundsException();
}
int remaining = len - off;
if (remaining == 0)
{
return;
}
byte[] buffer = new byte[Math.min(remaining, WRITE_CHUNK_SIZE)];
while (remaining > 0)
{
System.arraycopy(b, off, buffer, 0, Math.min(remaining, WRITE_CHUNK_SIZE));
// write at most WRITE_CHUNK_SIZE of data and at most the remaining bytes
out.write(buffer, 0, Math.min(remaining, WRITE_CHUNK_SIZE));
remaining -= buffer.length;
off += buffer.length;
}
}
/**
* Closes the underlying stream and releases OS resources associated with it. This will happen only
* if the wrapper is closable at this time. If the intent is to trully close the underlying stream,
* call {@code setClosable()} in advance.
*/
@Override
public void close()
{
if (closable && out != null)
{
out.closeOut();
out = null;
}
}
/**
* Flushes the underlying stream.
*/
@Override
public void flush() throws IOException
{
if (out != null)
{
out.flush();
}
}
/** Makes the stream closable back again by resetting the {@code closable} property. */
public void setClosable()
{
closable = true;
}
}