Commons Net example source code file (TimeTCPClient.java)

This example Commons Net source code file (TimeTCPClient.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Net tags/keywords

datainputstream, datainputstream, date, date, default_port, io, ioexception, ioexception, seconds_1900_to_1970, socketclient, timetcpclient, timetcpclient, util

The Commons Net TimeTCPClient.java source code

/*
 * 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.
 * <p>
 * <p>
 * @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 <code> 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.
     * <p>
     * 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 <code> getTime()  again.
     * <p>
     * @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.
     * <p>
     * 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 <code> getDate()  again.
     * <p>
     * @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);
    }

}