1 package org.apache.commons.net;
2
3 /* ====================================================================
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001 The Apache Software Foundation. All rights
7 * reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. The end-user documentation included with the redistribution,
22 * if any, must include the following acknowledgment:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
25 * Alternately, this acknowledgment may appear in the software itself,
26 * if and wherever such third-party acknowledgments normally appear.
27 *
28 * 4. The names "Apache" and "Apache Software Foundation" and
29 * "Apache Commons" must not be used to endorse or promote products
30 * derived from this software without prior written permission. For
31 * written permission, please contact apache@apache.org.
32 *
33 * 5. Products derived from this software may not be called "Apache",
34 * nor may "Apache" appear in their name, without
35 * prior written permission of the Apache Software Foundation.
36 *
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 * ====================================================================
50 *
51 * This software consists of voluntary contributions made by many
52 * individuals on behalf of the Apache Software Foundation. For more
53 * information on the Apache Software Foundation, please see
54 * <http://www.apache.org/>.
55 */
56
57 import java.io.IOException;
58 import java.util.Date;
59 import java.io.DataInputStream;
60
61 /****
62 * The TimeTCPClient class is a TCP implementation of a client for the
63 * Time protocol described in RFC 868. To use the class, merely
64 * establish a connection with
65 * <a href="org.apache.commons.net.SocketClient.html#connect"> connect </a>
66 * and call either <a href="#getTime"> getTime() </a> or
67 * <a href="#getDate"> getDate() </a> to retrieve the time, then
68 * call <a href="org.apache.commons.net.SocketClient.html#disconnect"> disconnect </a>
69 * to close the connection properly.
70 * <p>
71 * <p>
72 * @author Daniel F. Savarese
73 * @see TimeUDPClient
74 ***/
75
76 public final class TimeTCPClient extends SocketClient
77 {
78 /**** The default time port. It is set to 37 according to RFC 868. ***/
79 public static final int DEFAULT_PORT = 37;
80
81 /****
82 * The number of seconds between 00:00 1 January 1900 and
83 * 00:00 1 January 1970. This value can be useful for converting
84 * time values to other formats.
85 ***/
86 public static final long SECONDS_1900_TO_1970 = 2208988800L;
87
88 /****
89 * The default TimeTCPClient constructor. It merely sets the default
90 * port to <code> DEFAULT_PORT </code>.
91 ***/
92 public TimeTCPClient ()
93 {
94 setDefaultPort(DEFAULT_PORT);
95 }
96
97 /****
98 * Retrieves the time from the server and returns it. The time
99 * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
100 * as specified by RFC 868. This method reads the raw 32-bit big-endian
101 * unsigned integer from the server, converts it to a Java long, and
102 * returns the value.
103 * <p>
104 * The server will have closed the connection at this point, so you should
105 * call
106 * <a href="org.apache.commons.net.SocketClient.html#disconnect"> disconnect </a>
107 * after calling this method. To retrieve another time, you must
108 * initiate another connection with
109 * <a href="org.apache.commons.net.SocketClient.html#connect"> connect </a>
110 * before calling <code> getTime() </code> again.
111 * <p>
112 * @return The time value retrieved from the server.
113 * @exception IOException If an error occurs while fetching the time.
114 ***/
115 public long getTime() throws IOException
116 {
117 DataInputStream input;
118 input = new DataInputStream(_input_);
119 return (long)(input.readInt() & 0xffffffffL);
120 }
121
122 /****
123 * Retrieves the time from the server and returns a Java Date
124 * containing the time converted to the local timezone.
125 * <p>
126 * The server will have closed the connection at this point, so you should
127 * call
128 * <a href="org.apache.commons.net.SocketClient.html#disconnect"> disconnect </a>
129 * after calling this method. To retrieve another time, you must
130 * initiate another connection with
131 * <a href="org.apache.commons.net.SocketClient.html#connect"> connect </a>
132 * before calling <code> getDate() </code> again.
133 * <p>
134 * @return A Date value containing the time retrieved from the server
135 * converted to the local timezone.
136 * @exception IOException If an error occurs while fetching the time.
137 ***/
138 public Date getDate() throws IOException
139 {
140 return new Date((getTime() - SECONDS_1900_TO_1970)*1000L);
141 }
142
143 }
144
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