org.apache.commons.net.tftp
Class TFTPDataPacket

java.lang.Object
  extended byorg.apache.commons.net.tftp.TFTPPacket
      extended byorg.apache.commons.net.tftp.TFTPDataPacket

public final class TFTPDataPacket
extends TFTPPacket

A final class derived from TFTPPacket definiing the TFTP Data 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.

Author:
Daniel F. Savarese
See Also:
TFTPPacket, TFTPPacketException, TFTP

Field Summary
(package private)  int _blockNumber
          The block number of the packet.
(package private)  byte[] _data
          The data stored in the packet.
(package private)  int _length
          The length of the data.
(package private)  int _offset
          The offset into the _data array at which the data begins.
static int MAX_DATA_LENGTH
          The maximum number of bytes in a TFTP data packet (512)
static int MIN_DATA_LENGTH
          The minimum number of bytes in a TFTP data packet (0)
 
Fields inherited from class org.apache.commons.net.tftp.TFTPPacket
_address, _port, _type, ACKNOWLEDGEMENT, DATA, ERROR, MIN_PACKET_SIZE, READ_REQUEST, SEGMENT_SIZE, WRITE_REQUEST
 
Constructor Summary
(package private) TFTPDataPacket(java.net.DatagramPacket datagram)
          Creates a data packet based from a received datagram.
  TFTPDataPacket(java.net.InetAddress destination, int port, int blockNumber, byte[] data)
           
  TFTPDataPacket(java.net.InetAddress destination, int port, int blockNumber, byte[] data, int offset, int length)
          Creates a data packet to be sent to a host at a given port with a given block number.
 
Method Summary
(package private)  java.net.DatagramPacket _newDatagram(java.net.DatagramPacket datagram, byte[] data)
          This is a method only available within the package for implementing efficient datagram transport by elminating buffering.
 int getBlockNumber()
          Returns the block number of the data packet.
 byte[] getData()
          Returns the byte array containing the packet data.
 int getDataLength()
          Returns the length of the data part of the data packet.
 int getDataOffset()
          Returns the offset into the byte array where the packet data actually starts.
 java.net.DatagramPacket newDatagram()
          Creates a UDP datagram containing all the TFTP data packet data in the proper format.
 void setBlockNumber(int blockNumber)
          Sets the block number of the data packet.
 void setData(byte[] data, int offset, int length)
          Sets the data for the data packet.
 
Methods inherited from class org.apache.commons.net.tftp.TFTPPacket
getAddress, getPort, getType, newTFTPPacket, setAddress, setPort
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

MAX_DATA_LENGTH

public static final int MAX_DATA_LENGTH
The maximum number of bytes in a TFTP data packet (512)

See Also:
Constant Field Values

MIN_DATA_LENGTH

public static final int MIN_DATA_LENGTH
The minimum number of bytes in a TFTP data packet (0)

See Also:
Constant Field Values

_blockNumber

int _blockNumber
The block number of the packet.


_length

int _length
The length of the data.


_offset

int _offset
The offset into the _data array at which the data begins.


_data

byte[] _data
The data stored in the packet.

Constructor Detail

TFTPDataPacket

public TFTPDataPacket(java.net.InetAddress destination,
                      int port,
                      int blockNumber,
                      byte[] data,
                      int offset,
                      int length)
Creates a data packet to be sent to a host at a given port with a given block number. The actual data to be sent is passed as an array, an offset, and a length. The offset is the offset into the byte array where the data starts. The length is the length of the data. If the length is greater than MAX_DATA_LENGTH, it is truncated.

Parameters:
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 of the data.
data - The byte array containing the data.
offset - The offset into the array where the data starts.
length - The length of the data.

TFTPDataPacket

public TFTPDataPacket(java.net.InetAddress destination,
                      int port,
                      int blockNumber,
                      byte[] data)

TFTPDataPacket

TFTPDataPacket(java.net.DatagramPacket datagram)
         throws TFTPPacketException
Creates a data packet based from a received datagram. Assumes the datagram is at least length 4, else an ArrayIndexOutOfBoundsException may be thrown.

Parameters:
datagram - The datagram containing the received data.
Throws:
TFTPPacketException - If the datagram isn't a valid TFTP data packet.
Method Detail

_newDatagram

java.net.DatagramPacket _newDatagram(java.net.DatagramPacket datagram,
                                     byte[] data)
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.

Specified by:
_newDatagram in class TFTPPacket
Parameters:
datagram - The datagram to create.
data - The buffer to store the packet and to use in the datagram.
Returns:
The datagram argument.

newDatagram

public java.net.DatagramPacket newDatagram()
Creates a UDP datagram containing all the TFTP data 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.

Specified by:
newDatagram in class TFTPPacket
Returns:
A UDP datagram containing the TFTP data packet.

getBlockNumber

public int getBlockNumber()
Returns the block number of the data packet.

Returns:
The block number of the data packet.

setBlockNumber

public void setBlockNumber(int blockNumber)
Sets the block number of the data packet.


setData

public void setData(byte[] data,
                    int offset,
                    int length)
Sets the data for the data packet.

Parameters:
data - The byte array containing the data.
offset - The offset into the array where the data starts.
length - The length of the data.

getDataLength

public int getDataLength()
Returns the length of the data part of the data packet.

Returns:
The length of the data part of the data packet.

getDataOffset

public int getDataOffset()
Returns the offset into the byte array where the packet data actually starts.

Returns:
The offset into the byte array where the packet data actually starts.

getData

public byte[] getData()
Returns the byte array containing the packet data.

Returns:
The byte array containing the packet data.