http://commons.apache.org/proper/commons-net/: Apache Commons Net library contains a collection of network utilities and protocol implementations. Supported protocols include: Echo, Finger, FTP, NNTP, NTP, POP3(S), SMTP(S), Telnet, Whois (The Apache Software Foundation)
  • Henrik Sorensen
  • Jeff Nadler
  • William Noto
  • Stephane ESTE-GRACIAS
  • Dan Armbrust
  • Yuval Kashtan
  • Joseph Hindsley
  • Rob Hasselbaum
  • Mario Ivankovits
  • Naz Irizarry (MITRE Corp)
  • Tapan Karecha
  • Jason Mathews (MITRE Corp)
  • Winston Ojeda (Quad/Graphics, Inc.)
  • Ted Wise
  • Bogdan Drozdowski
  • Jeffrey D. Brekke (Quad/Graphics, Inc.)
  • Steve Cohen (javactivity.org)
  • Bruno D'Avanzo (Hewlett-Packard)
  • Daniel F. Savarese (<a href="http://www.savarese.com/">Savarese Software Research</a>)
  • Rory Winston ()
  • Rory Winston () 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.tftp;

import java.net.DatagramPacket;
import java.net.InetAddress;


A final class derived from TFTPPacket definiing the TFTP Acknowledgement
packet type.

 Details regarding the TFTP protocol and the format of TFTP packets can be found in RFC 783. But the point of these classes is to keep you from having to worry about the internals. Additionally, only very few people should have to care about any of the TFTPPacket classes or derived classes. Almost all users should only be concerned with the TFTPClient class receiveFile() and sendFile() methods. 
See Also:
/***
 * A final class derived from TFTPPacket definiing the TFTP Acknowledgement
 * packet type.
 * <p>
 * Details regarding the TFTP protocol and the format of TFTP packets can
 * be found in RFC 783.  But the point of these classes is to keep you
 * from having to worry about the internals.  Additionally, only very
 * few people should have to care about any of the TFTPPacket classes
 * or derived classes.  Almost all users should only be concerned with the
 * {@link org.apache.commons.net.tftp.TFTPClient} class
 * {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()}
 * and
 * {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()}
 * methods.
 *
 *
 * @see TFTPPacket
 * @see TFTPPacketException
 * @see TFTP
 ***/

public final class TFTPAckPacket extends TFTPPacket
{
    
The block number being acknowledged by the packet. 
/*** The block number being acknowledged by the packet. ***/
    int _blockNumber;

    
Creates an acknowledgment packet to be sent to a host at a given port
acknowledging receipt of a block.

Params:
  • destination –  The host to which the packet is going to be sent.
  • port –  The port to which the packet is going to be sent.
  • blockNumber –  The block number being acknowledged.
/***
     * Creates an acknowledgment packet to be sent to a host at a given port
     * acknowledging receipt of a block.
     *
     * @param destination  The host to which the packet is going to be sent.
     * @param port  The port to which the packet is going to be sent.
     * @param blockNumber  The block number being acknowledged.
     ***/
    public TFTPAckPacket(InetAddress destination, int port, int blockNumber)
    {
        super(TFTPPacket.ACKNOWLEDGEMENT, destination, port);
        _blockNumber = blockNumber;
    }

    
Creates an acknowledgement packet based from a received
datagram.  Assumes the datagram is at least length 4, else an
ArrayIndexOutOfBoundsException may be thrown.

Params:
  • datagram –  The datagram containing the received acknowledgement.
Throws:
/***
     * Creates an acknowledgement packet based from a received
     * datagram.  Assumes the datagram is at least length 4, else an
     * ArrayIndexOutOfBoundsException may be thrown.
     *
     * @param datagram  The datagram containing the received acknowledgement.
     * @throws TFTPPacketException  If the datagram isn't a valid TFTP
     *         acknowledgement packet.
     ***/
    TFTPAckPacket(DatagramPacket datagram) throws TFTPPacketException
    {
        super(TFTPPacket.ACKNOWLEDGEMENT, datagram.getAddress(),
              datagram.getPort());
        byte[] data;

        data = datagram.getData();

        if (getType() != data[1]) {
            throw new TFTPPacketException("TFTP operator code does not match type.");
        }

        _blockNumber = (((data[2] & 0xff) << 8) | (data[3] & 0xff));
    }

    
This is a method only available within the package for
implementing efficient datagram transport by elminating buffering.
It takes a datagram as an argument, and a byte buffer in which
to store the raw datagram data.  Inside the method, the data
is set as the datagram's data and the datagram returned.

Params:
  • datagram –  The datagram to create.
  • data – The buffer to store the packet and to use in the datagram.
Returns:The datagram argument.
/***
     * This is a method only available within the package for
     * implementing efficient datagram transport by elminating buffering.
     * It takes a datagram as an argument, and a byte buffer in which
     * to store the raw datagram data.  Inside the method, the data
     * is set as the datagram's data and the datagram returned.
     *
     * @param datagram  The datagram to create.
     * @param data The buffer to store the packet and to use in the datagram.
     * @return The datagram argument.
     ***/
    @Override
    DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
    {
        data[0] = 0;
        data[1] = (byte)_type;
        data[2] = (byte)((_blockNumber & 0xffff) >> 8);
        data[3] = (byte)(_blockNumber & 0xff);

        datagram.setAddress(_address);
        datagram.setPort(_port);
        datagram.setData(data);
        datagram.setLength(4);

        return datagram;
    }


    
Creates a UDP datagram containing all the TFTP acknowledgement packet data in the proper format. This is a method exposed to the programmer in case he wants to implement his own TFTP client instead of using the TFTPClient class. Under normal circumstances, you should not have a need to call this method. 
Returns:A UDP datagram containing the TFTP acknowledgement packet.
/***
     * Creates a UDP datagram containing all the TFTP
     * acknowledgement packet data in the proper format.
     * This is a method exposed to the programmer in case he
     * wants to implement his own TFTP client instead of using
     * the {@link org.apache.commons.net.tftp.TFTPClient}
     * class.  Under normal circumstances, you should not have a need to call this
     * method.
     *
     * @return A UDP datagram containing the TFTP acknowledgement packet.
     ***/
    @Override
    public DatagramPacket newDatagram()
    {
        byte[] data;

        data = new byte[4];
        data[0] = 0;
        data[1] = (byte)_type;
        data[2] = (byte)((_blockNumber & 0xffff) >> 8);
        data[3] = (byte)(_blockNumber & 0xff);

        return new DatagramPacket(data, data.length, _address, _port);
    }


    
Returns the block number of the acknowledgement.

Returns:The block number of the acknowledgement.
/***
     * Returns the block number of the acknowledgement.
     *
     * @return The block number of the acknowledgement.
     ***/
    public int getBlockNumber()
    {
        return _blockNumber;
    }


    
Sets the block number of the acknowledgement.

Params:
  • blockNumber – the number to set
/***
     * Sets the block number of the acknowledgement.
     *
     * @param blockNumber the number to set
     ***/
    public void setBlockNumber(int blockNumber)
    {
        _blockNumber = blockNumber;
    }

    
For debugging

Since:3.6
/**
     * For debugging
     * @since 3.6
     */
    @Override
    public String toString() {
        return super.toString() + " ACK " + _blockNumber;
    }
}