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}