/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.net.time; import java.io.DataInputStream; import java.io.IOException; import java.util.Date; import org.apache.commons.net.SocketClient; /*** * The TimeTCPClient class is a TCP implementation of a client for the * Time protocol described in RFC 868. To use the class, merely * establish a connection with * {@link org.apache.commons.net.SocketClient#connect connect } * and call either {@link #getTime getTime() } or * {@link #getDate getDate() } to retrieve the time, then * call {@link org.apache.commons.net.SocketClient#disconnect disconnect } * to close the connection properly. *
*
* @author Daniel F. Savarese
* @see TimeUDPClient
***/
public final class TimeTCPClient extends SocketClient
{
/*** The default time port. It is set to 37 according to RFC 868. ***/
public static final int DEFAULT_PORT = 37;
/***
* The number of seconds between 00:00 1 January 1900 and
* 00:00 1 January 1970. This value can be useful for converting
* time values to other formats.
***/
public static final long SECONDS_1900_TO_1970 = 2208988800L;
/***
* The default TimeTCPClient constructor. It merely sets the default
* port to DEFAULT_PORT
.
***/
public TimeTCPClient ()
{
setDefaultPort(DEFAULT_PORT);
}
/***
* Retrieves the time from the server and returns it. The time
* is the number of seconds since 00:00 (midnight) 1 January 1900 GMT,
* as specified by RFC 868. This method reads the raw 32-bit big-endian
* unsigned integer from the server, converts it to a Java long, and
* returns the value.
*
* The server will have closed the connection at this point, so you should
* call
* {@link org.apache.commons.net.SocketClient#disconnect disconnect }
* after calling this method. To retrieve another time, you must
* initiate another connection with
* {@link org.apache.commons.net.SocketClient#connect connect }
* before calling getTime()
again.
*
* @return The time value retrieved from the server. * @exception IOException If an error occurs while fetching the time. ***/ public long getTime() throws IOException { DataInputStream input; input = new DataInputStream(_input_); return (input.readInt() & 0xffffffffL); } /*** * Retrieves the time from the server and returns a Java Date * containing the time converted to the local timezone. *
* The server will have closed the connection at this point, so you should
* call
* {@link org.apache.commons.net.SocketClient#disconnect disconnect }
* after calling this method. To retrieve another time, you must
* initiate another connection with
* {@link org.apache.commons.net.SocketClient#connect connect }
* before calling getDate()
again.
*
* @return A Date value containing the time retrieved from the server * converted to the local timezone. * @exception IOException If an error occurs while fetching the time. ***/ public Date getDate() throws IOException { return new Date((getTime() - SECONDS_1900_TO_1970)*1000L); } }