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 * @author Daniel F. Savarese
38 * @see TimeUDPClient
39 ***/
40
41 public final class TimeTCPClient extends SocketClient
42 {
43 /*** The default time port. It is set to 37 according to RFC 868. ***/
44 public static final int DEFAULT_PORT = 37;
45
46 /***
47 * The number of seconds between 00:00 1 January 1900 and
48 * 00:00 1 January 1970. This value can be useful for converting
49 * time values to other formats.
50 ***/
51 public static final long SECONDS_1900_TO_1970 = 2208988800L;
52
53 /***
54 * The default TimeTCPClient constructor. It merely sets the default
55 * port to <code> DEFAULT_PORT </code>.
56 ***/
57 public TimeTCPClient ()
58 {
59 setDefaultPort(DEFAULT_PORT);
60 }
61
62 /***
63 * Retrieves the time from the server and returns it. The time
64 * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
65 * as specified by RFC 868. This method reads the raw 32-bit big-endian
66 * unsigned integer from the server, converts it to a Java long, and
67 * returns the value.
68 * <p>
69 * The server will have closed the connection at this point, so you should
70 * call
71 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
72 * after calling this method. To retrieve another time, you must
73 * initiate another connection with
74 * {@link org.apache.commons.net.SocketClient#connect connect }
75 * before calling <code> getTime() </code> again.
76 * <p>
77 * @return The time value retrieved from the server.
78 * @exception IOException If an error occurs while fetching the time.
79 ***/
80 public long getTime() throws IOException
81 {
82 DataInputStream input;
83 input = new DataInputStream(_input_);
84 return (input.readInt() & 0xffffffffL);
85 }
86
87 /***
88 * Retrieves the time from the server and returns a Java Date
89 * containing the time converted to the local timezone.
90 * <p>
91 * The server will have closed the connection at this point, so you should
92 * call
93 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
94 * after calling this method. To retrieve another time, you must
95 * initiate another connection with
96 * {@link org.apache.commons.net.SocketClient#connect connect }
97 * before calling <code> getDate() </code> again.
98 * <p>
99 * @return A Date value containing the time retrieved from the server
100 * converted to the local timezone.
101 * @exception IOException If an error occurs while fetching the time.
102 ***/
103 public Date getDate() throws IOException
104 {
105 return new Date((getTime() - SECONDS_1900_TO_1970)*1000L);
106 }
107
108 }
109