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 *      https://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 Discard protocol described in RFC 863. To use the class, just open a local UDP port
029 * with {@link org.apache.commons.net.DatagramSocketClient#open open} and call {@link #send send} to send datagrams to the server After you're done sending
030 * discard data, call {@link org.apache.commons.net.DatagramSocketClient#close close()} to clean up properly.
031 *
032 * @see DiscardTCPClient
033 */
034public class DiscardUDPClient extends DatagramSocketClient {
035
036    /** The default discard port. It is set to 9 according to RFC 863. */
037    public static final int DEFAULT_PORT = 9;
038
039    private final DatagramPacket sendPacket;
040
041    /**
042     * Constructs a new instance.
043     */
044    public DiscardUDPClient() {
045        sendPacket = new DatagramPacket(NetConstants.EMPTY_BTYE_ARRAY, 0);
046    }
047
048    /**
049     * Same as {@code send(data, data.length, host. DiscardUDPClient.DEFAULT_PORT)}.
050     *
051     * @param data the buffer to send
052     * @param host the target host
053     * @see #send(byte[], int, InetAddress, int)
054     * @throws IOException if an error occurs
055     */
056    public void send(final byte[] data, final InetAddress host) throws IOException {
057        send(data, data.length, host, DEFAULT_PORT);
058    }
059
060    /**
061     * Same as {@code send(data, length, host. DiscardUDPClient.DEFAULT_PORT)}.
062     *
063     * @param data   the buffer to send
064     * @param length the length of the data in the buffer
065     * @param host   the target host
066     * @see #send(byte[], int, InetAddress, int)
067     * @throws IOException if an error occurs
068     */
069    public void send(final byte[] data, final int length, final InetAddress host) throws IOException {
070        send(data, length, host, DEFAULT_PORT);
071    }
072
073    /**
074     * Sends the specified data to the specified server at the specified port.
075     *
076     * @param data   The discard data to send.
077     * @param length The length of the data to send. Should be less than or equal to the length of the data byte array.
078     * @param host   The address of the server.
079     * @param port   The service port.
080     * @throws IOException If an error occurs during the datagram send operation.
081     */
082    public void send(final byte[] data, final int length, final InetAddress host, final int port) throws IOException {
083        sendPacket.setData(data);
084        sendPacket.setLength(length);
085        sendPacket.setAddress(host);
086        sendPacket.setPort(port);
087        checkOpen().send(sendPacket);
088    }
089
090}