1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.daytime;
19
20 import java.io.BufferedReader;
21 import java.io.IOException;
22 import java.io.InputStreamReader;
23
24 import org.apache.commons.net.SocketClient;
25
26 /**
27 * The DaytimeTCPClient class is a TCP implementation of a client for the Daytime protocol described in RFC 867. To use the class, merely establish a connection
28 * with {@link org.apache.commons.net.SocketClient#connect connect } and call {@link #getTime getTime() } to retrieve the daytime string, then call
29 * {@link org.apache.commons.net.SocketClient#disconnect disconnect } to close the connection properly.
30 *
31 * @see DaytimeUDPClient
32 */
33 public final class DaytimeTCPClient extends SocketClient {
34 /** The default daytime port. It is set to 13 according to RFC 867. */
35 public static final int DEFAULT_PORT = 13;
36
37 // Received dates will likely be less than 64 characters.
38 // This is a temporary buffer used while receiving data.
39 private final char[] buffer = new char[64];
40
41 /**
42 * The default DaytimeTCPClient constructor. It merely sets the default port to <code>DEFAULT_PORT</code>.
43 */
44 public DaytimeTCPClient() {
45 setDefaultPort(DEFAULT_PORT);
46 }
47
48 /**
49 * Retrieves the time string from the server and returns it. The server will have closed the connection at this point, so you should call
50 * {@link org.apache.commons.net.SocketClient#disconnect disconnect } after calling this method. To retrieve another time, you must initiate another
51 * connection with {@link org.apache.commons.net.SocketClient#connect connect } before calling <code>getTime()</code> again.
52 *
53 * @return The time string retrieved from the server.
54 * @throws IOException If an error occurs while fetching the time string.
55 */
56 public String getTime() throws IOException {
57 int read;
58 final StringBuilder result = new StringBuilder(buffer.length);
59 final BufferedReader reader;
60
61 reader = new BufferedReader(new InputStreamReader(_input_, getCharset()));
62
63 while (true) {
64 read = reader.read(buffer, 0, buffer.length);
65 if (read <= 0) {
66 break;
67 }
68 result.append(buffer, 0, read);
69 }
70
71 return result.toString();
72 }
73
74 }