org.apache.commons.net.tftp

Class TFTP

Known Direct Subclasses:
TFTPClient

public class TFTP
extends DatagramSocketClient

The TFTP class exposes a set of methods to allow you to deal with the TFTP protocol directly, in case you want to write your own TFTP client or server. However, almost every user should only be concerend with the open(), and close(), methods. Additionally,the a setDefaultTimeout() method may be of importance for performance tuning.

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.

See Also:
DatagramSocketClient, TFTPPacket, TFTPPacketException, TFTPClient

Field Summary

static int
ASCII_MODE
The ascii transfer mode.
static int
BINARY_MODE
The binary transfer mode.
static int
DEFAULT_PORT
The default TFTP port according to RFC 783 is 69.
static int
DEFAULT_TIMEOUT
The default number of milliseconds to wait to receive a datagram before timing out.
static int
IMAGE_MODE
The image transfer mode.
static int
NETASCII_MODE
The netascii transfer mode.
static int
OCTET_MODE
The octet transfer mode.

Fields inherited from class org.apache.commons.net.DatagramSocketClient

_isOpen_, _socketFactory_, _socket_, _timeout_

Constructor Summary

TFTP()
Creates a TFTP instance with a default timeout of DEFAULT_TIMEOUT, a null socket, and buffered operations disabled.

Method Summary

void
beginBufferedOps()
Initializes the internal buffers.
TFTPPacket
bufferedReceive()
This is a special method to perform a more efficient packet receive.
void
bufferedSend(TFTPPacket packet)
This is a special method to perform a more efficient packet send.
void
discardPackets()
This method synchronizes a connection by discarding all packets that may be in the local socket buffer.
void
endBufferedOps()
Releases the resources used to perform buffered sends and receives.
static String
getModeName(int mode)
Returns the TFTP string representation of a TFTP transfer mode.
TFTPPacket
receive()
Receives a TFTPPacket.
void
send(TFTPPacket packet)
Sends a TFTP packet to its destination.

Methods inherited from class org.apache.commons.net.DatagramSocketClient

close, getDefaultTimeout, getLocalAddress, getLocalPort, getSoTimeout, isOpen, open, open, open, setDatagramSocketFactory, setDefaultTimeout, setSoTimeout

Field Details

ASCII_MODE

public static final int ASCII_MODE
The ascii transfer mode. Its value is 0 and equivalent to NETASCII_MODE

Field Value:
0


BINARY_MODE

public static final int BINARY_MODE
The binary transfer mode. Its value is 1 and equivalent to OCTET_MODE.

Field Value:
1


DEFAULT_PORT

public static final int DEFAULT_PORT
The default TFTP port according to RFC 783 is 69.

Field Value:
69


DEFAULT_TIMEOUT

public static final int DEFAULT_TIMEOUT
The default number of milliseconds to wait to receive a datagram before timing out. The default is 5000 milliseconds (5 seconds).

Field Value:
5000


IMAGE_MODE

public static final int IMAGE_MODE
The image transfer mode. Its value is 1 and equivalent to OCTET_MODE.

Field Value:
1


NETASCII_MODE

public static final int NETASCII_MODE
The netascii transfer mode. Its value is 0.

Field Value:
0


OCTET_MODE

public static final int OCTET_MODE
The octet transfer mode. Its value is 1.

Field Value:
1

Constructor Details

TFTP

public TFTP()
Creates a TFTP instance with a default timeout of DEFAULT_TIMEOUT, a null socket, and buffered operations disabled.

Method Details

beginBufferedOps

public final void beginBufferedOps()
Initializes the internal buffers. Buffers are used by bufferedSend() and bufferedReceive(). This method must be called before calling either one of those two methods. When you finish using buffered operations, you must call endBufferedOps().


bufferedReceive

public final TFTPPacket bufferedReceive()
            throws IOException,
                   InterruptedIOException,
                   SocketException,
                   TFTPPacketException
This is a special method to perform a more efficient packet receive. It should only be used after calling beginBufferedOps(). beginBufferedOps() initializes a set of buffers used internally that prevent the new allocation of a DatagramPacket and byte array for each send and receive. To use these buffers you must call the bufferedReceive() and bufferedSend() methods instead of send() and receive(). You must also be certain that you don't manipulate the resulting packet in such a way that it interferes with future buffered operations. For example, a TFTPDataPacket received with bufferedReceive() will have a reference to the internal byte buffer. You must finish using this data before calling bufferedReceive() again, or else the data will be overwritten by the the call.

Returns:
The TFTPPacket received.

Throws:
TFTPPacketException - If an invalid TFTP packet is received.


bufferedSend

public final void bufferedSend(TFTPPacket packet)
            throws IOException
This is a special method to perform a more efficient packet send. It should only be used after calling beginBufferedOps(). beginBufferedOps() initializes a set of buffers used internally that prevent the new allocation of a DatagramPacket and byte array for each send and receive. To use these buffers you must call the bufferedReceive() and bufferedSend() methods instead of send() and receive(). You must also be certain that you don't manipulate the resulting packet in such a way that it interferes with future buffered operations. For example, a TFTPDataPacket received with bufferedReceive() will have a reference to the internal byte buffer. You must finish using this data before calling bufferedReceive() again, or else the data will be overwritten by the the call.

Parameters:
packet - The TFTP packet to send.


discardPackets

public final void discardPackets()
            throws IOException
This method synchronizes a connection by discarding all packets that may be in the local socket buffer. This method need only be called when you implement your own TFTP client or server.


endBufferedOps

public final void endBufferedOps()
Releases the resources used to perform buffered sends and receives.


getModeName

public static final String getModeName(int mode)
Returns the TFTP string representation of a TFTP transfer mode. Will throw an ArrayIndexOutOfBoundsException if an invalid transfer mode is specified.

Parameters:
mode - The TFTP transfer mode. One of the MODE constants.

Returns:
The TFTP string representation of the TFTP transfer mode.


receive

public final TFTPPacket receive()
            throws IOException,
                   InterruptedIOException,
                   SocketException,
                   TFTPPacketException
Receives a TFTPPacket.

Returns:
The TFTPPacket received.

Throws:
TFTPPacketException - If an invalid TFTP packet is received.


send

public final void send(TFTPPacket packet)
            throws IOException
Sends a TFTP packet to its destination.

Parameters:
packet - The TFTP packet to send.