1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.net.echo; 19 20 import java.io.IOException; 21 import java.net.DatagramPacket; 22 import java.net.InetAddress; 23 24 import org.apache.commons.net.discard.DiscardUDPClient; 25 26 /*** 27 * The EchoUDPClient class is a UDP implementation of a client for the 28 * Echo protocol described in RFC 862. To use the class, 29 * just open a local UDP port 30 * with {@link org.apache.commons.net.DatagramSocketClient#open open } 31 * and call {@link #send send } to send datagrams to the server, 32 * then call {@link #receive receive } to receive echoes. 33 * After you're done echoing data, call 34 * {@link org.apache.commons.net.DatagramSocketClient#close close() } 35 * to clean up properly. 36 * <p> 37 * <p> 38 * @see EchoTCPClient 39 * @see DiscardUDPClient 40 ***/ 41 42 public final class EchoUDPClient extends DiscardUDPClient 43 { 44 /*** The default echo port. It is set to 7 according to RFC 862. ***/ 45 public static final int DEFAULT_PORT = 7; 46 47 private final DatagramPacket __receivePacket = new DatagramPacket(new byte[0], 0); 48 49 /*** 50 * Sends the specified data to the specified server at the default echo 51 * port. 52 * <p> 53 * @param data The echo data to send. 54 * @param length The length of the data to send. Should be less than 55 * or equal to the length of the data byte array. 56 * @param host The address of the server. 57 * @exception IOException If an error occurs during the datagram send 58 * operation. 59 ***/ 60 @Override 61 public void send(byte[] data, int length, InetAddress host) 62 throws IOException 63 { 64 send(data, length, host, DEFAULT_PORT); 65 } 66 67 68 /*** Same as <code> send(data, data.length, host) </code> ***/ 69 @Override 70 public void send(byte[] data, InetAddress host) throws IOException 71 { 72 send(data, data.length, host, DEFAULT_PORT); 73 } 74 75 76 /*** 77 * Receives echoed data and returns its length. The data may be divided 78 * up among multiple datagrams, requiring multiple calls to receive. 79 * Also, the UDP packets will not necessarily arrive in the same order 80 * they were sent. 81 * <p> 82 * @return Length of actual data received. 83 * @exception IOException If an error occurs while receiving the data. 84 ***/ 85 public int receive(byte[] data, int length) throws IOException 86 { 87 __receivePacket.setData(data); 88 __receivePacket.setLength(length); 89 _socket_.receive(__receivePacket); 90 return __receivePacket.getLength(); 91 } 92 93 /*** Same as <code> receive(data, data.length)</code> ***/ 94 public int receive(byte[] data) throws IOException 95 { 96 return receive(data, data.length); 97 } 98 99 } 100