| /* |
| * 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.daytime; |
| |
| import java.io.IOException; |
| import java.net.DatagramPacket; |
| import java.net.InetAddress; |
| |
| import org.apache.commons.net.DatagramSocketClient; |
| |
| /** |
| * 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 |
| * {@link org.apache.commons.net.DatagramSocketClient#open open } |
| * and call {@link #getTime getTime } to retrieve the daytime |
| * string, then |
| * call {@link org.apache.commons.net.DatagramSocketClient#close close } |
| * to close the connection properly. Unlike |
| * {@link org.apache.commons.net.daytime.DaytimeTCPClient}, |
| * successive calls to {@link #getTime getTime } are permitted |
| * without re-establishing a connection. That is because UDP is a |
| * connectionless protocol and the Daytime protocol is stateless. |
| * @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 final byte[] __dummyData = new byte[1]; |
| // Received dates should be less than 256 bytes |
| private final 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. |
| * @throws 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(), getCharsetName()); // Java 1.6 can use getCharset() |
| } |
| |
| /** Same as <code>getTime(host, DaytimeUDPClient.DEFAULT_PORT);</code> |
| * @param host the host |
| * @return the time |
| * @throws IOException on error |
| */ |
| public String getTime(InetAddress host) throws IOException |
| { |
| return getTime(host, DEFAULT_PORT); |
| } |
| |
| } |
| |