File	Doc	Category	Size	Date	Package
TFTPDataPacket.java	API Doc	Apache Commons NET 1.4.1 API	7925	Sat Dec 03 10:05:50 GMT 2005	org.apache.commons.net.tftp

TFTPDataPacket

• java.lang.Object
  • TFTPPacket

Fields Summary
public static final int	MAX_DATA_LENGTH The maximum number of bytes in a TFTP data packet (512)
public static final int	MIN_DATA_LENGTH The minimum number of bytes in a TFTP data packet (0)
int	_blockNumber The block number of the packet.
int	_length The length of the data.
int	_offset The offset into the _data array at which the data begins.
byte[]	_data The data stored in the packet.

Constructors Summary
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. 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 of the data. param data The byte array containing the data. param offset The offset into the array where the data starts. param length The length of the data. super(TFTPPacket.DATA, destination, port); _blockNumber = blockNumber; _data = data; _offset = offset; if (length > MAX_DATA_LENGTH) _length = MAX_DATA_LENGTH; else _length = length;
public TFTPDataPacket(InetAddress destination, int port, int blockNumber, byte[] data) this(destination, port, blockNumber, data, 0, data.length);
TFTPDataPacket(DatagramPacket datagram) Creates a data 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 data. throws TFTPPacketException If the datagram isn't a valid TFTP data packet. super(TFTPPacket.DATA, datagram.getAddress(), datagram.getPort()); _data = datagram.getData(); _offset = 4; if (getType() != _data[1]) throw new TFTPPacketException("TFTP operator code does not match type."); _blockNumber = (((_data[2] & 0xff) << 8) | (_data[3] & 0xff)); _length = datagram.getLength() - 4; if (_length > MAX_DATA_LENGTH) _length = MAX_DATA_LENGTH;

Methods Summary
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. param datagram The datagram to create. param data The buffer to store the packet and to use in the datagram. return The datagram argument. data[0] = 0; data[1] = (byte)_type; data[2] = (byte)((_blockNumber & 0xffff) >> 8); data[3] = (byte)(_blockNumber & 0xff); // Doublecheck we're not the same if (data != _data) System.arraycopy(_data, _offset, data, 4, _length); datagram.setAddress(_address); datagram.setPort(_port); datagram.setData(data); datagram.setLength(_length + 4); return datagram;
public int	getBlockNumber() Returns the block number of the data packet. return The block number of the data packet. return _blockNumber;
public byte[]	getData() Returns the byte array containing the packet data. return The byte array containing the packet data. return _data;
public int	getDataLength() Returns the length of the data part of the data packet. return The length of the data part of the data packet. return _length;
public int	getDataOffset() Returns the offset into the byte array where the packet data actually starts. return The offset into the byte array where the packet data actually starts. return _offset;
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 {@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 data packet. byte[] data; data = new byte[_length + 4]; data[0] = 0; data[1] = (byte)_type; data[2] = (byte)((_blockNumber & 0xffff) >> 8); data[3] = (byte)(_blockNumber & 0xff); System.arraycopy(_data, _offset, data, 4, _length); return new DatagramPacket(data, _length + 4, _address, _port);
public void	setBlockNumber(int blockNumber) Sets the block number of the data packet. _blockNumber = blockNumber;
public void	setData(byte[] data, int offset, int length) Sets the data for the data packet. param data The byte array containing the data. param offset The offset into the array where the data starts. param length The length of the data. _data = data; _offset = offset; _length = length; if (length > MAX_DATA_LENGTH) _length = MAX_DATA_LENGTH; else _length = length;