org.apache.commons.net.tftp

Class 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

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) **
(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.

Fields inherited from class org.apache.commons.net.tftp.TFTPPacket

ACKNOWLEDGEMENT, DATA, ERROR, MIN_PACKET_SIZE, READ_REQUEST, SEGMENT_SIZE, WRITE_REQUEST, _address, _port, _type

Constructor Summary

TFTPDataPacket(DatagramPacket datagram)
Creates a data packet based from a received datagram.
TFTPDataPacket(InetAddress destination, int port, int blockNumber, byte[] data)
TFTPDataPacket(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) DatagramPacket
_newDatagram(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.
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

_newDatagram, getAddress, getPort, getType, newDatagram, newTFTPPacket, setAddress, setPort

Field Details

MAX_DATA_LENGTH

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

Field Value:
512


MIN_DATA_LENGTH

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

Field Value:
0


_blockNumber

(package private)  int _blockNumber
The block number of the packet. **


_data

(package private)  byte[] _data
The data stored in the packet. **


_length

(package private)  int _length
The length of the data. **


_offset

(package private)  int _offset
The offset into the _data array at which the data begins. **

Constructor Details

TFTPDataPacket

(package private)  TFTPDataPacket(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.


TFTPDataPacket

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


TFTPDataPacket

public TFTPDataPacket(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.

Method Details

_newDatagram

(package private)  DatagramPacket _newDatagram(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.

Overrides:
_newDatagram in interface TFTPPacket

Parameters:
datagram - The datagram to create.
data - The buffer to store the packet and to use in the datagram.

Returns:
The datagram argument.


getBlockNumber

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

Returns:
The block number of the data packet.


getData

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

Returns:
The byte array containing the packet 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.


newDatagram

public DatagramPacket newDatagram()
Overrides:
newDatagram in interface TFTPPacket

Returns:
A UDP datagram containing the TFTP 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.