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.time;
19
20 import java.io.DataInputStream;
21 import java.io.IOException;
22 import java.util.Date;
23
24 import org.apache.commons.net.SocketClient;
25
26 /***
27 * The TimeTCPClient class is a TCP implementation of a client for the
28 * Time protocol described in RFC 868. To use the class, merely
29 * establish a connection with
30 * {@link org.apache.commons.net.SocketClient#connect connect }
31 * and call either {@link #getTime getTime() } or
32 * {@link #getDate getDate() } to retrieve the time, then
33 * call {@link org.apache.commons.net.SocketClient#disconnect disconnect }
34 * to close the connection properly.
35 * <p>
36 * <p>
37 * @see TimeUDPClient
38 ***/
39
40 public final class TimeTCPClient extends SocketClient
41 {
42 /*** The default time port. It is set to 37 according to RFC 868. ***/
43 public static final int DEFAULT_PORT = 37;
44
45 /***
46 * The number of seconds between 00:00 1 January 1900 and
47 * 00:00 1 January 1970. This value can be useful for converting
48 * time values to other formats.
49 ***/
50 public static final long SECONDS_1900_TO_1970 = 2208988800L;
51
52 /***
53 * The default TimeTCPClient constructor. It merely sets the default
54 * port to <code> DEFAULT_PORT </code>.
55 ***/
56 public TimeTCPClient ()
57 {
58 setDefaultPort(DEFAULT_PORT);
59 }
60
61 /***
62 * Retrieves the time from the server and returns it. The time
63 * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
64 * as specified by RFC 868. This method reads the raw 32-bit big-endian
65 * unsigned integer from the server, converts it to a Java long, and
66 * returns the value.
67 * <p>
68 * The server will have closed the connection at this point, so you should
69 * call
70 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
71 * after calling this method. To retrieve another time, you must
72 * initiate another connection with
73 * {@link org.apache.commons.net.SocketClient#connect connect }
74 * before calling <code> getTime() </code> again.
75 * <p>
76 * @return The time value retrieved from the server.
77 * @exception IOException If an error occurs while fetching the time.
78 ***/
79 public long getTime() throws IOException
80 {
81 DataInputStream input;
82 input = new DataInputStream(_input_);
83 return (input.readInt() & 0xffffffffL);
84 }
85
86 /***
87 * Retrieves the time from the server and returns a Java Date
88 * containing the time converted to the local timezone.
89 * <p>
90 * The server will have closed the connection at this point, so you should
91 * call
92 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
93 * after calling this method. To retrieve another time, you must
94 * initiate another connection with
95 * {@link org.apache.commons.net.SocketClient#connect connect }
96 * before calling <code> getDate() </code> again.
97 * <p>
98 * @return A Date value containing the time retrieved from the server
99 * converted to the local timezone.
100 * @exception IOException If an error occurs while fetching the time.
101 ***/
102 public Date getDate() throws IOException
103 {
104 return new Date((getTime() - SECONDS_1900_TO_1970)*1000L);
105 }
106
107 }
108