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Java > Open Source Codes > org > apache > commons > net > EchoUDPClient


1 /*
2  * Copyright 2001-2005 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.net;
17
18 import java.io.IOException JavaDoc;
19 import java.net.DatagramPacket JavaDoc;
20 import java.net.InetAddress JavaDoc;
21
22 /***
23  * The EchoUDPClient class is a UDP implementation of a client for the
24  * Echo protocol described in RFC 862. To use the class,
25  * just open a local UDP port
26  * with {@link org.apache.commons.net.DatagramSocketClient#open open }
27  * and call {@link #send send } to send datagrams to the server,
28  * then call {@link #receive receive } to receive echoes.
29  * After you're done echoing data, call
30  * {@link org.apache.commons.net.DatagramSocketClient#close close() }
31  * to clean up properly.
32  * <p>
33  * <p>
34  * @author Daniel F. Savarese
35  * @see EchoTCPClient
36  * @see DiscardUDPClient
37  ***/
38
39 public final class EchoUDPClient extends DiscardUDPClient
40 {
41     /*** The default echo port. It is set to 7 according to RFC 862. ***/
42     public static final int DEFAULT_PORT = 7;
43
44     private DatagramPacket JavaDoc __receivePacket = new DatagramPacket JavaDoc(new byte[0], 0);
45
46     /***
47      * Sends the specified data to the specified server at the default echo
48      * port.
49      * <p>
50      * @param data The echo data to send.
51      * @param length The length of the data to send. Should be less than
52      * or equal to the length of the data byte array.
53      * @param host The address of the server.
54      * @exception IOException If an error occurs during the datagram send
55      * operation.
56      ***/
57     public void send(byte[] data, int length, InetAddress JavaDoc host)
58     throws IOException JavaDoc
59     {
60         send(data, length, host, DEFAULT_PORT);
61     }
62
63
64     /*** Same as <code> send(data, data.length, host) </code> ***/
65     public void send(byte[] data, InetAddress JavaDoc host) throws IOException JavaDoc
66     {
67         send(data, data.length, host, DEFAULT_PORT);
68     }
69
70
71     /***
72      * Receives echoed data and returns its length. The data may be divided
73      * up among multiple datagrams, requiring multiple calls to receive.
74      * Also, the UDP packets will not necessarily arrive in the same order
75      * they were sent.
76      * <p>
77      * @return Length of actual data received.
78      * @exception IOException If an error occurs while receiving the data.
79      ***/
80     public int receive(byte[] data, int length) throws IOException JavaDoc
81     {
82         __receivePacket.setData(data);
83         __receivePacket.setLength(length);
84         _socket_.receive(__receivePacket);
85         return __receivePacket.getLength();
86     }
87
88     /*** Same as <code> receive(data, data.length)</code> ***/
89     public int receive(byte[] data) throws IOException JavaDoc
90     {
91         return receive(data, data.length);
92     }
93
94 }
95
96
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