public class TFTP extends DatagramSocketClient
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.
DatagramSocketClient
,
TFTPPacket
,
TFTPPacketException
,
TFTPClient
Modifier and Type | Field and Description |
---|---|
private byte[] |
__receiveBuffer
A buffer used to accelerate receives in bufferedReceive()
|
private java.net.DatagramPacket |
__receiveDatagram
A datagram used to minimize memory allocation in bufferedReceive()
|
private java.net.DatagramPacket |
__sendDatagram
A datagram used to minimize memory allocation in bufferedSend()
|
(package private) byte[] |
_sendBuffer
A buffer used to accelerate sends in bufferedSend().
|
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.
|
(package private) static int |
PACKET_SIZE
The size to use for TFTP packet buffers.
|
_isOpen_, _socket_, _socketFactory_, _timeout_
Constructor and Description |
---|
TFTP()
Creates a TFTP instance with a default timeout of DEFAULT_TIMEOUT,
a null socket, and buffered operations disabled.
|
Modifier and Type | Method and Description |
---|---|
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 java.lang.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.
|
protected void |
trace(java.lang.String direction,
TFTPPacket packet)
Trace facility; this implementation does nothing.
|
close, getCharset, getCharsetName, getDefaultTimeout, getLocalAddress, getLocalPort, getSoTimeout, isOpen, open, open, open, setCharset, setDatagramSocketFactory, setDefaultTimeout, setSoTimeout
public static final int ASCII_MODE
public static final int NETASCII_MODE
public static final int BINARY_MODE
public static final int IMAGE_MODE
public static final int OCTET_MODE
public static final int DEFAULT_TIMEOUT
public static final int DEFAULT_PORT
static final int PACKET_SIZE
private byte[] __receiveBuffer
private java.net.DatagramPacket __receiveDatagram
private java.net.DatagramPacket __sendDatagram
byte[] _sendBuffer
public TFTP()
public static final java.lang.String getModeName(int mode)
mode
- The TFTP transfer mode. One of the MODE constants.public final void discardPackets() throws java.io.IOException
java.io.IOException
- if an I/O error occurs.public final TFTPPacket bufferedReceive() throws java.io.IOException, java.io.InterruptedIOException, java.net.SocketException, TFTPPacketException
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.java.io.InterruptedIOException
- If a socket timeout occurs. The
Java documentation claims an InterruptedIOException is thrown
on a DatagramSocket timeout, but in practice we find a
SocketException is thrown. You should catch both to be safe.java.net.SocketException
- If a socket timeout occurs. The
Java documentation claims an InterruptedIOException is thrown
on a DatagramSocket timeout, but in practice we find a
SocketException is thrown. You should catch both to be safe.java.io.IOException
- If some other I/O error occurs.TFTPPacketException
- If an invalid TFTP packet is received.public final void bufferedSend(TFTPPacket packet) throws java.io.IOException
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.packet
- The TFTP packet to send.java.io.IOException
- If some I/O error occurs.public final void beginBufferedOps()
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()
.public final void endBufferedOps()
public final void send(TFTPPacket packet) throws java.io.IOException
packet
- The TFTP packet to send.java.io.IOException
- If some I/O error occurs.public final TFTPPacket receive() throws java.io.IOException, java.io.InterruptedIOException, java.net.SocketException, TFTPPacketException
java.io.InterruptedIOException
- If a socket timeout occurs. The
Java documentation claims an InterruptedIOException is thrown
on a DatagramSocket timeout, but in practice we find a
SocketException is thrown. You should catch both to be safe.java.net.SocketException
- If a socket timeout occurs. The
Java documentation claims an InterruptedIOException is thrown
on a DatagramSocket timeout, but in practice we find a
SocketException is thrown. You should catch both to be safe.java.io.IOException
- If some other I/O error occurs.TFTPPacketException
- If an invalid TFTP packet is received.protected void trace(java.lang.String direction, TFTPPacket packet)
Override it to trace the data, for example:
System.out.println(direction + " " + packet.toString());
direction
- ">" or "<"packet
- the packet to be sent or that has been received