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TFTPErrorPacket.javaAPI DocApache Commons NET 1.4.1 API6962Sat Dec 03 10:05:50 GMT 2005org.apache.commons.net.tftp

TFTPErrorPacket

public final class TFTPErrorPacket extends TFTPPacket
A final class derived from TFTPPacket definiing the TFTP Error 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 {@link org.apache.commons.net.tftp.TFTPClient} class {@link org.apache.commons.net.tftp.TFTPClient#receiveFile receiveFile()} and {@link org.apache.commons.net.tftp.TFTPClient#sendFile sendFile()} methods.

author
Daniel F. Savarese
see
TFTPPacket
see
TFTPPacketException
see
TFTP

Fields Summary
public static final int
UNDEFINED
The undefined error code according to RFC 783, value 0.
public static final int
FILE_NOT_FOUND
The file not found error code according to RFC 783, value 1.
public static final int
ACCESS_VIOLATION
The access violation error code according to RFC 783, value 2.
public static final int
OUT_OF_SPACE
The disk full error code according to RFC 783, value 3.
public static final int
ILLEGAL_OPERATION
The illegal TFTP operation error code according to RFC 783, value 4.
public static final int
UNKNOWN_TID
The unknown transfer id error code according to RFC 783, value 5.
public static final int
FILE_EXISTS
The file already exists error code according to RFC 783, value 6.
public static final int
NO_SUCH_USER
The no such user error code according to RFC 783, value 7.
int
_error
The error code of this packet.
String
_message
The error message of this packet.
Constructors Summary
public TFTPErrorPacket(InetAddress destination, int port, int error, String message)
Creates an error packet to be sent to a host at a given port with an error code and error message.

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
error The error code of the packet.
param
message The error message of the packet.


                                                                           
        
                              
    
        super(TFTPPacket.ERROR, destination, port);

        _error = error;
        _message = message;
TFTPErrorPacket(DatagramPacket datagram)
Creates an error 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 error.
throws
TFTPPacketException If the datagram isn't a valid TFTP error packet.

        super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
        int index, length;
        byte[] data;
        StringBuffer buffer;

        data = datagram.getData();
        length = datagram.getLength();

        if (getType() != data[1])
            throw new TFTPPacketException("TFTP operator code does not match type.");

        _error = (((data[2] & 0xff) << 8) | (data[3] & 0xff));

        if (length < 5)
            throw new TFTPPacketException("Bad error packet. No message.");

        index = 4;
        buffer = new StringBuffer();

        while (index < length && data[index] != 0)
        {
            buffer.append((char)data[index]);
            ++index;
        }

        _message = buffer.toString();
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.

        int length;

        length = _message.length();

        data[0] = 0;
        data[1] = (byte)_type;
        data[2] = (byte)((_error & 0xffff) >> 8);
        data[3] = (byte)(_error & 0xff);

        System.arraycopy(_message.getBytes(), 0, data, 4, length);

        data[length + 4] = 0;

        datagram.setAddress(_address);
        datagram.setPort(_port);
        datagram.setData(data);
        datagram.setLength(length + 4);

        return datagram;
public intgetError()
Returns the error code of the packet.

return
The error code of the packet.

        return _error;
public java.lang.StringgetMessage()
Returns the error message of the packet.

return
The error message of the packet.

        return _message;
public java.net.DatagramPacketnewDatagram()
Creates a UDP datagram containing all the TFTP error 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 error packet.

        byte[] data;
        int length;

        length = _message.length();

        data = new byte[length + 5];
        data[0] = 0;
        data[1] = (byte)_type;
        data[2] = (byte)((_error & 0xffff) >> 8);
        data[3] = (byte)(_error & 0xff);

        System.arraycopy(_message.getBytes(), 0, data, 4, length);

        data[length + 4] = 0;

        return new DatagramPacket(data, data.length, _address, _port);