| /* |
| * 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 Acknowledgement |
| * 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 TFTPAckPacket extends TFTPPacket |
| { |
| /*** The block number being acknowledged by the packet. ***/ |
| int blockNumber; |
| |
| /*** |
| * Creates an acknowledgment packet to be sent to a host at a given port |
| * acknowledging receipt of a block. |
| * |
| * @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 being acknowledged. |
| ***/ |
| public TFTPAckPacket(final InetAddress destination, final int port, final int blockNumber) |
| { |
| super(TFTPPacket.ACKNOWLEDGEMENT, destination, port); |
| this.blockNumber = blockNumber; |
| } |
| |
| /*** |
| * Creates an acknowledgement 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 acknowledgement. |
| * @throws TFTPPacketException If the datagram isn't a valid TFTP |
| * acknowledgement packet. |
| ***/ |
| TFTPAckPacket(final DatagramPacket datagram) throws TFTPPacketException |
| { |
| super(TFTPPacket.ACKNOWLEDGEMENT, datagram.getAddress(), |
| datagram.getPort()); |
| byte[] data; |
| |
| data = datagram.getData(); |
| |
| if (getType() != data[1]) { |
| throw new TFTPPacketException("TFTP operator code does not match type."); |
| } |
| |
| this.blockNumber = (((data[2] & 0xff) << 8) | (data[3] & 0xff)); |
| } |
| |
| /*** |
| * 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(final DatagramPacket datagram, final byte[] data) |
| { |
| data[0] = 0; |
| data[1] = (byte)type; |
| data[2] = (byte)((blockNumber & 0xffff) >> 8); |
| data[3] = (byte)(blockNumber & 0xff); |
| |
| datagram.setAddress(address); |
| datagram.setPort(port); |
| datagram.setData(data); |
| datagram.setLength(4); |
| |
| return datagram; |
| } |
| |
| |
| /*** |
| * Creates a UDP datagram containing all the TFTP |
| * acknowledgement 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 acknowledgement packet. |
| ***/ |
| @Override |
| public DatagramPacket newDatagram() |
| { |
| byte[] data; |
| |
| data = new byte[4]; |
| data[0] = 0; |
| data[1] = (byte)type; |
| data[2] = (byte)((blockNumber & 0xffff) >> 8); |
| data[3] = (byte)(blockNumber & 0xff); |
| |
| return new DatagramPacket(data, data.length, address, port); |
| } |
| |
| |
| /*** |
| * Returns the block number of the acknowledgement. |
| * |
| * @return The block number of the acknowledgement. |
| ***/ |
| public int getBlockNumber() |
| { |
| return blockNumber; |
| } |
| |
| |
| /*** |
| * Sets the block number of the acknowledgement. |
| * |
| * @param blockNumber the number to set |
| ***/ |
| public void setBlockNumber(final int blockNumber) |
| { |
| this.blockNumber = blockNumber; |
| } |
| |
| /** |
| * For debugging |
| * @since 3.6 |
| */ |
| @Override |
| public String toString() { |
| return super.toString() + " ACK " + blockNumber; |
| } |
| } |
| |