001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.net.time;
019
020 import java.io.DataInputStream;
021 import java.io.IOException;
022 import java.util.Date;
023
024 import org.apache.commons.net.SocketClient;
025
026 /***
027 * The TimeTCPClient class is a TCP implementation of a client for the
028 * Time protocol described in RFC 868. To use the class, merely
029 * establish a connection with
030 * {@link org.apache.commons.net.SocketClient#connect connect }
031 * and call either {@link #getTime getTime() } or
032 * {@link #getDate getDate() } to retrieve the time, then
033 * call {@link org.apache.commons.net.SocketClient#disconnect disconnect }
034 * to close the connection properly.
035 * <p>
036 * <p>
037 * @see TimeUDPClient
038 ***/
039
040 public final class TimeTCPClient extends SocketClient
041 {
042 /*** The default time port. It is set to 37 according to RFC 868. ***/
043 public static final int DEFAULT_PORT = 37;
044
045 /***
046 * The number of seconds between 00:00 1 January 1900 and
047 * 00:00 1 January 1970. This value can be useful for converting
048 * time values to other formats.
049 ***/
050 public static final long SECONDS_1900_TO_1970 = 2208988800L;
051
052 /***
053 * The default TimeTCPClient constructor. It merely sets the default
054 * port to <code> DEFAULT_PORT </code>.
055 ***/
056 public TimeTCPClient ()
057 {
058 setDefaultPort(DEFAULT_PORT);
059 }
060
061 /***
062 * Retrieves the time from the server and returns it. The time
063 * is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
064 * as specified by RFC 868. This method reads the raw 32-bit big-endian
065 * unsigned integer from the server, converts it to a Java long, and
066 * returns the value.
067 * <p>
068 * The server will have closed the connection at this point, so you should
069 * call
070 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
071 * after calling this method. To retrieve another time, you must
072 * initiate another connection with
073 * {@link org.apache.commons.net.SocketClient#connect connect }
074 * before calling <code> getTime() </code> again.
075 * <p>
076 * @return The time value retrieved from the server.
077 * @exception IOException If an error occurs while fetching the time.
078 ***/
079 public long getTime() throws IOException
080 {
081 DataInputStream input;
082 input = new DataInputStream(_input_);
083 return (input.readInt() & 0xffffffffL);
084 }
085
086 /***
087 * Retrieves the time from the server and returns a Java Date
088 * containing the time converted to the local timezone.
089 * <p>
090 * The server will have closed the connection at this point, so you should
091 * call
092 * {@link org.apache.commons.net.SocketClient#disconnect disconnect }
093 * after calling this method. To retrieve another time, you must
094 * initiate another connection with
095 * {@link org.apache.commons.net.SocketClient#connect connect }
096 * before calling <code> getDate() </code> again.
097 * <p>
098 * @return A Date value containing the time retrieved from the server
099 * 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