# 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;
       }
    }