# NIONetSocketBase.java

    /*
    ** Module   : NIONetSocketBase.java
    ** Abstract : Implements NetSocket operations which are common for all NIO-based implementations.
    **
    ** Copyright (c) 2016-2021, Golden Code Development Corporation.
    **
    ** -#- -I- --Date--  ---------------------------------------Description---------------------------------------
    ** 001 IAS 20160805  Initial version
    ** 002 IAS 20200729  Process large messages
    ** 003 IAS 20210329  Re-worked logging configuration
    */
    /*
    ** 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.net;

    import java.io.*;
    import java.net.*;
    import java.nio.*;
    import java.nio.channels.*;
    import java.util.logging.*;

    import com.goldencode.p2j.util.*;

    /**
     * Implements NetSocket operations which are common for all NIO-based implementations.
     */
    public abstract class NIONetSocketBase
    extends NetSocketBase
    implements NetSocket
    {

       /** Underlying SocketChannel instance */
       protected final SocketChannel channel;

       /**
        * Constructor
        *
        * @param channel
        *        underlying SocketChannel instance
        * @throws   IOException
        *           on error
        */
       NIONetSocketBase(SocketChannel channel)
       throws IOException
       {
          this.channel = channel;

    //      this.channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
          this.channel.setOption(StandardSocketOptions.TCP_NODELAY, true);
          this.channel.setOption(StandardSocketOptions.SO_SNDBUF, BUF_SIZE);
          this.channel.setOption(StandardSocketOptions.SO_RCVBUF, BUF_SIZE);
       }

       /**
        * Closes the socket.
        */
       @Override
       public void close()
       {
          try
          {
             channel.close();
          }
          catch (IOException ex)
          {
             // best efforts
          }
       }

       /**
        * Reports if the socket is closed (and thus can no longer be used).
        *
        * @return   <code>true</code> if the socket is closed.
        */
       @Override
       public boolean isClosed()
       {
          return !channel.isOpen();
       }

       /**
        * Access the address of the local system, through which we are connecting.
        *
        * @return   The local address.
        */
       @Override
       public InetAddress getLocalAddr()
       {
          return channel.socket().getLocalAddress();
       }

       /**
        * Access the address of the local system, through which we are connecting.
        *
        * @return   The local socket address.
        */
       @Override
       public InetSocketAddress getLocalSockAddr()
       {
          return new InetSocketAddress(channel.socket().getLocalAddress(), channel.socket().getLocalPort());
       }

       /**
        * Access the address of the remote system, to which we are connecting.
        *
        * @return   The remote address.
        */
       @Override
       public InetAddress getRemoteAddr()
       {
          return channel.socket().getInetAddress();
       }

       /**
        * Access the address of the remote system, to which we are connecting.
        *
        * @return   The remote socket address.
        */
       @Override
       public InetSocketAddress getRemoteSockAddr()
       {
          return new InetSocketAddress(channel.socket().getInetAddress(), channel.socket().getPort());
       }

       /**
        * Write byte array to the output
        *
        * @param data
        *        byte array
        * @throws IOException
        */
       public void write(byte[] data)
       throws IOException
       {
          ByteBuffer wbuf;
          int maxMessageSize = getMaxMessageSize();
          int total = data.length;
          if (total + 4 < maxMessageSize)
          {
             wbuf = ByteBuffer.allocate(4 + data.length);
             wbuf.putInt(data.length);
             wbuf.put(data);
             wbuf.flip();
             write(wbuf);
             return;
          }
          if (TRACE_LM)
          {
             NetSocketBase.LOG.finest(
                   String.format("Long message to be sent. length: %d", data.length));
          }
          wbuf = ByteBuffer.allocate(4);
          wbuf.putInt(-total);
          wbuf.flip();
          write(wbuf);

          int pos = 0;
          while (total > 0)
          {
             int msgSize = Math.min(4 + total, maxMessageSize);
             wbuf = ByteBuffer.allocate(msgSize);
             msgSize -= 4;
             wbuf.putInt(msgSize);
             wbuf.put(data, pos, msgSize);
             wbuf.flip();
             write(wbuf);
             pos += msgSize;
             total -= msgSize;
             if (TRACE_LM)
             {
                NetSocketBase.LOG.finest(
                      String.format("Next chunk of long message sent. length: %d; remains: %d",
                            msgSize, total));
             }
          }
          if (TRACE_LM)
          {
             NetSocketBase.LOG.finest(
                   String.format("Long message sent. length: %d", data.length));
          }
     }

       /**
        * Read the next portion of raw data (byte array) to the output
        *
        * @return byte array
        */
       @Override
       public byte[] read()
       throws IOException
       {
          try
          {
             return readFully();
          }
          catch (ClosedChannelException e)
          {
             throw new EOFException();
          }
       }

       /**
        * Read the integer from the input
        *
        * @return integer data
        */
       @Override
       public int readInt()
       throws IOException
       {
          byte[] b = readFully();
          if (b.length != 4)
          {
             throw new IllegalStateException(String.format("Unexpected byte array length: %s instead of %s ",
                                                           b.length, 4));
          }
          return ByteBuffer.wrap(b).getInt();
       }

       /**
        * Write an integer to the output
        *
        * @param val
        *        integer data to be written
        */
       @Override
       public void writeInt(int val)
       throws IOException
       {
          ByteBuffer bb = ByteBuffer.allocate(8);
          bb.putInt(4).putInt(val);
          bb.flip();
          write(bb);
       }

       /**
        * Read the byte sequence from the input
        *
        * @param bytes
        *        byte array to be filled by the input bytes
        */
       @Override
       public void readBytes(byte[] bytes)
       throws IOException
       {
          try
          {
             byte[] b = readFully();
             if (b.length != bytes.length)
             {
                throw new IllegalStateException(String.format("Unexpected byte array length: %s instead of %s ",
                                                              b.length, bytes.length));
             }
             System.arraycopy(b, 0, bytes, 0, bytes.length);
          }
          catch (ClosedChannelException e)
          {
             throw new EOFException();
          }

       }

       /**
        * Write a byte sequence to the output
        *
        * @param bytes
        *        byte sequence to be written
        */
       @Override
       public void writeBytes(byte[] bytes)
       throws IOException
       {
          write(bytes);
       }

       /**
        * Read the boolean from the input
        *
        * @return boolean data
        */
       @Override
       public boolean readBoolean()
       throws IOException
       {
          byte[] b = readFully();
          if (b.length != 1)
          {
             throw new IllegalStateException(String.format("Unexpected byte array length: %s instead of %s ",
                                                           b.length, 1));
          }
          return b[0] != 0;
       }

       /**
        * Write a boolean to the output
        *
        * @param val
        *        boolean data to be written
        */
       @Override
       public void writeBoolean(boolean val)
       throws IOException
       {
          ByteBuffer bb = ByteBuffer.allocate(5);
          bb.putInt(1).put((byte)(val ? 1 : 0));
          bb.flip();
          write(bb);
       }

       /**
        * Read the UTF string from the input
        *
        * @return UTF string
        */
       @Override
       public String readUTF()
       throws IOException
       {
          byte[] data = readFully();
          ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data));
          return ois.readUTF();
       }

       /**
        * Write an UTF String to the output
        *
        * @param val
        *        UTF String to be written
        */
       @Override
       public void writeUTF(String val)
       throws IOException
       {
          ByteArrayOutputStream bos = new ByteArrayOutputStream();
          ObjectOutputStream oos = new ObjectOutputStream(bos);
          oos.writeUTF(val);
          oos.flush();
          oos.close();
          write(bos.toByteArray());
       }

       /**
        * Send the data to the channel
        *
        * @param bb
        *        data to be sent
        * @throws   IOException
        *           on error
        */
       protected abstract void write(ByteBuffer bb)
       throws IOException;

       /**
        * Read next data chunk from the channel
        *
        * @return next data chunk
        * @throws   IOException
        *           on error
        * @throws   EOFException
        *           if no data can be read
        */
       protected abstract byte[] readFully()
       throws IOException,
              EOFException;

       /**
        * Get maximal message size
        *
        * @return maximal message size;
        */
       protected int getMaxMessageSize()
       {
          return Integer.MAX_VALUE;
       }
    }