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This file 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.

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The source code

/*
 * Copyright 2001-2004 The Apache Software Foundation
 *
 * Licensed 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;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;

/***
 * The DaytimeUDPClient class is a UDP implementation of a client for the
 * Daytime protocol described in RFC 867.  To use the class, merely
 * open a local datagram socket with
 *  open 
 * and call  getTime  to retrieve the daytime
 * string, then
 * call  close 
 * to close the connection properly.  Unlike
 *  DaytimeTCPClient ,
 * successive calls to  getTime  are permitted
 * without re-establishing a connection.  That is because UDP is a
 * connectionless protocol and the Daytime protocol is stateless.
 * 

*

* @author Daniel F. Savarese * @see DaytimeTCPClient ***/ public final class DaytimeUDPClient extends DatagramSocketClient { /*** The default daytime port. It is set to 13 according to RFC 867. ***/ public static final int DEFAULT_PORT = 13; private byte[] __dummyData = new byte[1]; // Received dates should be less than 256 bytes private byte[] __timeData = new byte[256]; /*** * Retrieves the time string from the specified server and port and * returns it. *

* @param host The address of the server. * @param port The port of the service. * @return The time string. * @exception IOException If an error occurs while retrieving the time. ***/ public String getTime(InetAddress host, int port) throws IOException { DatagramPacket sendPacket, receivePacket; sendPacket = new DatagramPacket(__dummyData, __dummyData.length, host, port); receivePacket = new DatagramPacket(__timeData, __timeData.length); _socket_.send(sendPacket); _socket_.receive(receivePacket); return new String(receivePacket.getData(), 0, receivePacket.getLength()); } /*** Same as getTime(host, DaytimeUDPClient.DEFAULT_PORT); ***/ public String getTime(InetAddress host) throws IOException { return getTime(host, DEFAULT_PORT); } }

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