/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.net.tftp;

import java.net.DatagramPacket;
import java.net.InetAddress;

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 TFTPClient class receiveFile() and sendFile() methods. 
See Also:
TFTPPacket
TFTPPacketException
TFTP/***
 * A final class derived from TFTPPacket definiing the TFTP Error
 * packet type.
 * <p>
 * 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.
 *
 *
 * @see TFTPPacket
 * @see TFTPPacketException
 * @see TFTP
 ***/

public final class TFTPErrorPacket extends TFTPPacket
{
    
The undefined error code according to RFC 783, value 0. /*** The undefined error code according to RFC 783, value 0. ***/
    public static final int UNDEFINED = 0;

    
The file not found error code according to RFC 783, value 1. /*** The file not found error code according to RFC 783, value 1. ***/
    public static final int FILE_NOT_FOUND = 1;

    
The access violation error code according to RFC 783, value 2. /*** The access violation error code according to RFC 783, value 2. ***/
    public static final int ACCESS_VIOLATION = 2;

    
The disk full error code according to RFC 783, value 3. /*** The disk full error code according to RFC 783, value 3. ***/
    public static final int OUT_OF_SPACE = 3;

    
The illegal TFTP operation error code according to RFC 783, value 4.
/***
     * The illegal TFTP operation error code according to RFC 783, value 4.
     ***/
    public static final int ILLEGAL_OPERATION = 4;

    
The unknown transfer id error code according to RFC 783, value 5. /*** The unknown transfer id error code according to RFC 783, value 5. ***/
    public static final int UNKNOWN_TID = 5;

    
The file already exists error code according to RFC 783, value 6. /*** The file already exists error code according to RFC 783, value 6. ***/
    public static final int FILE_EXISTS = 6;

    
The no such user error code according to RFC 783, value 7. /*** The no such user error code according to RFC 783, value 7. ***/
    public static final int NO_SUCH_USER = 7;

    
The error code of this packet. /*** The error code of this packet. ***/
    int _error;

    
The error message of this packet. /*** The error message of this packet. ***/
    String _message;

    
Creates an error packet to be sent to a host at a given port
with an error code and error message.
Params:
destination –  The host to which the packet is going to be sent.
port –  The port to which the packet is going to be sent.
error – The error code of the packet.
message – The error message of the packet./***
     * 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.
     ***/
    public TFTPErrorPacket(InetAddress destination, int port,
                           int error, String message)
    {
        super(TFTPPacket.ERROR, destination, port);

        _error = error;
        _message = message;
    }

    
Creates an error packet based from a received
datagram.  Assumes the datagram is at least length 4, else an
ArrayIndexOutOfBoundsException may be thrown.
Params:
datagram –  The datagram containing the received error.
Throws:
TFTPPacketException –  If the datagram isn't a valid TFTP
        error packet./***
     * 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.
     ***/
    TFTPErrorPacket(DatagramPacket datagram) throws TFTPPacketException
    {
        super(TFTPPacket.ERROR, datagram.getAddress(), datagram.getPort());
        int index, length;
        byte[] data;
        StringBuilder 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 StringBuilder();

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

        _message = buffer.toString();
    }

    
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.
Params:
datagram –  The datagram to create.
data – The buffer to store the packet and to use in the datagram.
Returns:
The datagram argument./***
     * 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.
     ***/
    @Override
    DatagramPacket _newDatagram(DatagramPacket datagram, byte[] data)
    {
        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;
    }


    
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 TFTPClient class. Under normal circumstances, you should not have a need to call this method. 
Returns:
A UDP datagram containing the TFTP error packet./***
     * 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.
     ***/
    @Override
    public DatagramPacket newDatagram()
    {
        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);
    }


    
Returns the error code of the packet.
Returns:
The error code of the packet./***
     * Returns the error code of the packet.
     *
     * @return The error code of the packet.
     ***/
    public int getError()
    {
        return _error;
    }


    
Returns the error message of the packet.
Returns:
The error message of the packet./***
     * Returns the error message of the packet.
     *
     * @return The error message of the packet.
     ***/
    public String getMessage()
    {
        return _message;
    }

    
For debugging
Since:
3.6/**
     * For debugging
     * @since 3.6
     */
    @Override
    public String toString() {
        return super.toString() + " ERR " + _error + " " + _message;
    }
}