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 * @author Daniel F. Savarese
39 * @see EchoTCPClient
40 * @see DiscardUDPClient
41 ***/
42
43 public final class EchoUDPClient extends DiscardUDPClient
44 {
45 /*** The default echo port. It is set to 7 according to RFC 862. ***/
46 public static final int DEFAULT_PORT = 7;
47
48 private DatagramPacket __receivePacket = new DatagramPacket(new byte[0], 0);
49
50 /***
51 * Sends the specified data to the specified server at the default echo
52 * port.
53 * <p>
54 * @param data The echo data to send.
55 * @param length The length of the data to send. Should be less than
56 * or equal to the length of the data byte array.
57 * @param host The address of the server.
58 * @exception IOException If an error occurs during the datagram send
59 * operation.
60 ***/
61 @Override
62 public void send(byte[] data, int length, InetAddress host)
63 throws IOException
64 {
65 send(data, length, host, DEFAULT_PORT);
66 }
67
68
69 /*** Same as <code> send(data, data.length, host) </code> ***/
70 @Override
71 public void send(byte[] data, InetAddress host) throws IOException
72 {
73 send(data, data.length, host, DEFAULT_PORT);
74 }
75
76
77 /***
78 * Receives echoed data and returns its length. The data may be divided
79 * up among multiple datagrams, requiring multiple calls to receive.
80 * Also, the UDP packets will not necessarily arrive in the same order
81 * they were sent.
82 * <p>
83 * @return Length of actual data received.
84 * @exception IOException If an error occurs while receiving the data.
85 ***/
86 public int receive(byte[] data, int length) throws IOException
87 {
88 __receivePacket.setData(data);
89 __receivePacket.setLength(length);
90 _socket_.receive(__receivePacket);
91 return __receivePacket.getLength();
92 }
93
94 /*** Same as <code> receive(data, data.length)</code> ***/
95 public int receive(byte[] data) throws IOException
96 {
97 return receive(data, data.length);
98 }
99
100 }
101