001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.discard;
019
020import java.io.IOException;
021import java.net.DatagramPacket;
022import java.net.InetAddress;
023
024import org.apache.commons.net.DatagramSocketClient;
025import org.apache.commons.net.util.NetConstants;
026
027/**
028 * The DiscardUDPClient class is a UDP implementation of a client for the
029 * Discard protocol described in RFC 863.  To use the class,
030 * just open a local UDP port
031 * with {@link org.apache.commons.net.DatagramSocketClient#open  open }
032 * and call {@link #send  send } to send datagrams to the server
033 * After you're done sending discard data, call
034 * {@link org.apache.commons.net.DatagramSocketClient#close  close() }
035 * to clean up properly.
036 *
037 * @see DiscardTCPClient
038 */
039
040public class DiscardUDPClient extends DatagramSocketClient
041{
042    /** The default discard port.  It is set to 9 according to RFC 863. */
043    public static final int DEFAULT_PORT = 9;
044
045    private final DatagramPacket sendPacket;
046
047    public DiscardUDPClient()
048    {
049        sendPacket = new DatagramPacket(NetConstants.EMPTY_BTYE_ARRAY, 0);
050    }
051
052
053    /**
054     * Sends the specified data to the specified server at the specified port.
055     *
056     * @param data  The discard data to send.
057     * @param length  The length of the data to send.  Should be less than
058     *    or equal to the length of the data byte array.
059     * @param host  The address of the server.
060     * @param port  The service port.
061     * @throws IOException If an error occurs during the datagram send
062     *            operation.
063     */
064    public void send(final byte[] data, final int length, final InetAddress host, final int port)
065    throws IOException
066    {
067        sendPacket.setData(data);
068        sendPacket.setLength(length);
069        sendPacket.setAddress(host);
070        sendPacket.setPort(port);
071        _socket_.send(sendPacket);
072    }
073
074
075    /**
076     * Same as
077     * <code>send(data, length, host. DiscardUDPClient.DEFAULT_PORT)</code>.
078     * @param data the buffer to send
079     * @param length the length of the data in the buffer
080     * @param host the target host
081     * @see #send(byte[], int, InetAddress, int)
082     * @throws IOException if an error occurs
083     */
084    public void send(final byte[] data, final int length, final InetAddress host)
085    throws IOException
086    {
087        send(data, length, host, DEFAULT_PORT);
088    }
089
090
091    /**
092     * Same as
093     * <code>send(data, data.length, host. DiscardUDPClient.DEFAULT_PORT)</code>.
094     * @param data the buffer to send
095     * @param host the target host
096     * @see #send(byte[], int, InetAddress, int)
097     * @throws IOException if an error occurs
098     */
099    public void send(final byte[] data, final InetAddress host) throws IOException
100    {
101        send(data, data.length, host, DEFAULT_PORT);
102    }
103
104}
105