pongmessage.java

P2P协议GUNTELLA的java源代码

/*
 * Copyright (C) 2000-2001  Ken McCrary
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Email: [e-mail]
 */
package com.kenmccrary.jtella;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import com.kenmccrary.jtella.util.Log;

/**
 *  A Pong message is sent in reply to a Ping and provides host information
 *
 */
public class PongMessage extends Message
{
  private short port;
  private String ipAddress;
  private int fileCount;
  private int fileSize;
  
  /**
   *  Construct a PONG message 
   *
   *  @param port listening port
   *  @param ipAddress ipAdress for servant
   *  @param fileCount shared file count
   *  @param fileSize shared file size in KB
   */
  PongMessage(short port, String ipAddress, int fileCount, int fileSize)
  {
    super(Message.PONG);
    init(port, ipAddress, fileCount, fileSize);
  }
  
  /**
   *  Construct a PONG message 
   *
   *  @param GUID specific guid, generally from PING
   *  @param port listening port
   *  @param ipAddress ipAdress for servant
   *  @param fileCount shared file count
   *  @param fileSize shared file size in KB
   */
  PongMessage(GUID guid, 
              short port, 
              String ipAddress, 
              int fileCount, 
              int fileSize)
  {
    super(guid, Message.PONG);
    init(port, ipAddress, fileCount, fileSize);
  }
    

  /**
   *  Construct a PongMessage from data read from network
   *
   *  @param rawMessage binary data from a connection
   *  @param originatingConnection Connection creating this message
   */
  PongMessage(short[] rawMessage, Connection originatingConnection)
  {
    super(rawMessage, originatingConnection);
  }
  
  /**
   *  Construct a Pong message using a Host from the cache
   *
   *  @param host
   */
  PongMessage(Host host)
  {
    this((short)host.getPort(), 
         host.getIPAddress(), 
         host.getSharedFileCount(), 
         host.getSharedFileSize());
  }
  
  /**
   *  Common init
   *
   *  @param GUID specific guid, generally from PING
   *  @param port listening port
   *  @param ipAddress ipAdress for servant
   *  @param fileCount shared file count
   *  @param fileSize shared file size in KB
   *
   */
  private void init(short port, String ipAddress, int fileCount, int fileSize)
  {
    this.port = port;
    this.ipAddress = ipAddress;
    this.fileCount = fileCount;
    this.fileSize = fileSize;
    
    buildPayload();
  }

/*
 *  Payload 0-1 Port (little endian)
 *          2-5 IP address (little endian)
 *          6-9 shared file count
 *          10-13 total shared file size in kb
 */

  /**
   *  Query the IP address for this pong message
   *  result is an IP address in the form of
   *  "206.26.48.100".
   *
   *  @return IP address
   */
  String getIPAddress()
  {
    StringBuffer ipBuffer = new StringBuffer();

    ipBuffer.append(Integer.toString(payload[2])).
             append(".").
             append(Integer.toString(payload[3])).
             append(".").
             append(Integer.toString(payload[4])).
             append(".").
             append(Integer.toString(payload[5]));

    return ipBuffer.toString();
  }

  /**
   *  Query the port for this pong message
   *
   *  @return port
   */
  int getPort()
  {
    int port = 0;
    int byte1 = 0;
    int byte2 = 0;
    byte1 |= payload[0];
    byte2 |= payload[1];
    port |= byte1;
    port |= (byte2 << 8);
    return port;
  }

  /**
   *  Get the number of shared files
   *
   *  @return shared files
   */
  int getSharedFileCount()
  {
    int byte1 = payload[6];
    int byte2 = payload[7];
    int byte3 = payload[8];
    int byte4 = payload[9];
    
    return byte1 | (byte2 << 8 | byte3 << 16 | byte4 << 24);

  }
  
  /**
   *  Get the size of shared files
   *
   *  @return size
   */
  int getSharedFileSize()
  {
    int byte1 = payload[10];
    int byte2 = payload[11];
    int byte3 = payload[12];
    int byte4 = payload[13];
    
    return byte1 | (byte2 << 8 | byte3 << 16 | byte4 << 24);
  }
  
  /**
   *   Builds the PONG message payload
   *
   */
  void buildPayload()
  {
    try
    {
      ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
      DataOutputStream dataStream = new DataOutputStream(byteStream);
     
      // write the port, little endian
      int byte1 = 0x00FF & port;
      int byte2 = (0xFF00 & port) >> 8;
      dataStream.write(byte1);
      dataStream.write(byte2);
        
      // write the ip address
      
      // IP Address, little endian
      int beginIndex = 0;
      int endIndex = ipAddress.indexOf('.');

      int ip1 = Integer.parseInt(ipAddress.substring(beginIndex, endIndex));

      beginIndex = endIndex + 1;
      endIndex = ipAddress.indexOf('.', beginIndex);

      int ip2 = Integer.parseInt(ipAddress.substring(beginIndex, endIndex));

      beginIndex = endIndex + 1;
      endIndex = ipAddress.indexOf('.', beginIndex);

      int ip3 = Integer.parseInt(ipAddress.substring(beginIndex, endIndex));

      beginIndex = endIndex + 1;

      int ip4 = Integer.parseInt(ipAddress.substring(beginIndex, ipAddress.length()));

      dataStream.write(ip1);
      dataStream.write(ip2);
      dataStream.write(ip3);
      dataStream.write(ip4);
       
      // write the number of files
      int fileCountByte1 = 0x000000FF & fileCount;
      int fileCountByte2 = (0x0000FF00 & fileCount) >> 8;
      int fileCountByte3 = (0x00FF0000 & fileCount) >> 16;
      int fileCountByte4 = (0xFF000000 & fileCount) >> 24;
      dataStream.writeByte(fileCountByte1);
      dataStream.writeByte(fileCountByte2);
      dataStream.writeByte(fileCountByte3);
      dataStream.writeByte(fileCountByte4);
      
      // write the file size
      int fileSizeByte1 = 0x000000FF & fileSize;
      int fileSizeByte2 = (0x0000FF00 & fileSize) >> 8;
      int fileSizeByte3 = (0x00FF0000 & fileSize) >> 16;
      int fileSizeByte4 = (0xFF000000 & fileSize) >> 24;
      dataStream.writeByte(fileSizeByte1);
      dataStream.writeByte(fileSizeByte2);
      dataStream.writeByte(fileSizeByte3);
      dataStream.writeByte(fileSizeByte4);
      
      addPayload(byteStream.toByteArray());
      dataStream.close();

    }    
    catch (IOException io)
    {
    }   
  }    


}