# NullStream.java

    /*
    ** Module   : NullStream.java
    ** Abstract : represents a stream instance that is safe to call for any
    **            processing but which is a NOP
    **
    ** Copyright (c) 2006-2022, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- --JPRM-- ----------------------------Description----------------------------
    ** 001 GES 20060323   @25207 Created initial version which represents a
    **                           stream instance that is safe to call for any
    **                           processing but which is a NOP.
    ** 002 NVS 20070725   @34687 Implemented methods isIn() and isOut(), which
    **                           are newly added to the base class as abstract.
    ** 003 GES 20090625   @42944 Allow isIn() and isOut() to return true. This
    **                           avoid read/write errors on "closed" streams which
    **                           is how Progress silently deals with this case.
    ** 004 SVL 20110403          Added write(byte[]) function.
    ** 005 OM  20170622          Implemented peekCh() method.
    ** 006 ECF 20171026          Added write(byte[], int, int) method.
    ** 007 EVL 20220325          Base refactoring for Stream based classes getting single byte and array of bytes.
    */

    /*
    ** 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.*;

    import com.goldencode.p2j.net.*;
    import com.goldencode.p2j.security.ContextLocal;

    /**
     * A stream class which represents a stream instance that is safe to call for
     * any processing but which is in actuality a no operation.
     *
     * @author    GES
     */
    public class NullStream
    extends Stream
    {
       /**
        * Create a default instance.
        */
       public NullStream()
       {
          // no data, nothing to do
       }

       /**
        * The number of bytes available to be immediately read without blocking.
        *
        * @return   Always 0.
        */
       public long available()
       {
          return (long) 0;
       }

       /**
        * The 0-based offset into the stream at which the next read or write will
        * occur.
        *
        * @return   Always 0.
        */
       public long getPos()
       {
          return (long) 0;
       }

       /**
        * Moves the current read/write position to the specified absolute 0-based
        * offset, in actuality this has no effect.
        *
        * @param    pos
        *           The new read/write position in the stream.
        */
       public void setPos(long pos)
       {
          // nothing to do
       }

       /**
        * State of the input side of the stream.
        *
        * @return   Always <code>true</code>.
        */
       public boolean isIn()
       {
          return true;
       }

       /**
        * State of the output side of the stream.
        *
        * @return   Always <code>true</code>.
        */
       public boolean isOut()
       {
          return true;
       }

       /**
        * The length of the stream in bytes.
        *
        * @return   Always 0.
        */
       public long getLen()
       {
          return (long) 0;
       }

       /**
        * Truncates or extends the stream to the specified length if this stream
        * supports such an operation, in actuality this has no effect.
        *
        * @param    len
        *           Ignored.
        */
       public void setLen(long len)
       {
          // nothing to do
       }

       /**
        * Write the given character to the output stream, in actuality this has
        * no effect.
        *
        * @param    ch
        *           Ignored.
        */
       public void writeCh(char ch)
       {
          // nothing to do
       }

       /**
        * Write the given byte to the output stream, in actuality this has no
        * effect.
        *
        * @param    b
        *           Ignored.
        */
       public void writeByte(byte b)
       {
          // nothing to do
       }

       /**
        * Write the given string to the output stream, in actuality this has no
        * effect.
        *
        * @param    data
        *           Ignored.
        */
       public void write(String data)
       {
          // nothing to do
       }

       /**
        * Write the given byte array to the output stream, in actuality this has
        * no effect.
        *
        * @param    data
        *           Ignored.
        */
       public void write(byte[] data)
       {
          // nothing to do
       }

       /**
        * Write the specified range of bytes from the given byte array to the output stream.
        * Implemented as a no-op.
        *
        * @param    data
        *           The data to be written.
        * @param    off
        *           Starting offset in data from which to read bytes to be written. Must be
        *           non-negative and {@code &lt; data.length}.
        * @param    len
        *           Length of data to be written. Must be non-negative and {@code &lt;= (data.length
        *           - offset)}.
        *
        * @throws   IOException
        *           If an I/O error occurs.
        */
       public void write(byte[] data, int off, int len)
       throws IOException
       {
          // nothing to do
       }

       /**
        * Read a character from the current read position in the stream.
        *
        * @return   Always -2 (simulates an {@code EOF}).
        */
       public int peekCh()
       {
          return -2;
       }

       /**
        * Read a character from the current read position in the stream.
        *
        * @return   Always -2 (simulates an <code>EOF</code>).
        */
       public int readCh()
       {
          return -2;
       }

       /**
        * Read a single byte from the underlying stream.
        *
        * @return   A single byte from the stream, -1 on any failure and -2 upon an {@code EOF}.
        */
       @Override
       public int readByte()
       {
          return -2;
       }

       /**
        * Read all characters from the current read position in the stream to the
        * next line separator (as determined by the <code>File.separator</code>
        * or to the <code>EOF</code>. Any line separator character(s) and the
        * <code>EOF</code> character are not returned.  In actuality this has no
        * effect.
        *
        * @return   Always throws an <code>EOFException</code>.
        */
       public String readLn()
       throws EOFException
       {
          throw new EOFException("There is no stream.");
       }

       /**
        * Closes the input stream and releases OS resources associated with it,
        * in actuality this has no effect.
        */
       public void closeIn()
       {
          // nothing to do
       }

       /**
        * Closes the output stream and releases OS resources associated with it,
        * in actuality this has no effect.
        */
       public void closeOut()
       {
          // nothing to do
       }

       /**
        * Closes the stream and releases OS resources associated with it, in
        * actuality this has no effect.
        */
       public void close()
       {
          // nothing to do
       }

       /**
        * Assigns the internal stream reference to the given reference, in
        * actuality this has no effect.
        *
        * @param    s
        *           The new internal stream reference to use for all operations,
        *           ignored.
        */
       public void assign(Stream s)
       {
          // nothing to do
       }

       /**
        * Perform common close <b>preprocessing</b> for all streams, in actuality
        * this has no effect.
        *
        * @param    in
        *           Ignored.
        * @param    out
        *           Ignored.
        */
       protected void cleanup(boolean in, boolean out)
       throws IOException
       {
          // nothing to do
       }

       /**
        * Detects when a page break is needed.
        *
        * @return   Always <code>false</code>.
        */
       boolean needsPageBreak()
       {
          return false;
       }

       /**
        * Gets the current page size in lines.
        *
        * @return   Always 0.
        */
       int rawGetPageSize()
       {
          return 0;
       }

       /**
        * Sets the current page size in lines, in actuality this has no effect.
        *
        * @param    sz
        *           Ignored.
        */
       void rawSetPageSize(int sz)
       {
          // nothing to do
       }

       /**
        * Gets the current page number.
        *
        * @return   Always 0.
        */
       int rawGetPageNum()
       {
          return 0;
       }

       /**
        * Increments the current page number, in actuality this has no effect.
        */
       void rawIncrementPageNum()
       {
          // nothing to do
       }

       /**
        * Gets the current page's next line number.
        *
        * @return   Always 0.
        */
       int rawGetNextLineNum()
       {
          return 0;
       }

       /**
        * Increments the current page's next line number, in actuality this has
        * no effect.
        */
       void rawIncrementNextLineNum()
       {
          // nothing to do
       }

       /**
        * Resets the current page's next line number to 1, in actuality this has
        * no effect.
        */
       void rawResetNextLineNum()
       {
          // nothing to do
       }
    }