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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
28   * Daytime protocol described in RFC 867.  To use the class, merely
29   * establish a connection with
30   * {@link org.apache.commons.net.SocketClient#connect  connect }
31   * and call {@link #getTime  getTime() } to retrieve the daytime
32   * string, then
33   * call {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
34   * to close the connection properly.
35   * @see DaytimeUDPClient
36   */
37  public final class DaytimeTCPClient extends SocketClient
38  {
39      /** The default daytime port.  It is set to 13 according to RFC 867. */
40      public static final int DEFAULT_PORT = 13;
41  
42      // Received dates will likely be less than 64 characters.
43      // This is a temporary buffer used while receiving data.
44      private final char[] __buffer = new char[64];
45  
46      /**
47       * The default DaytimeTCPClient constructor.  It merely sets the default
48       * port to <code> DEFAULT_PORT </code>.
49       */
50      public DaytimeTCPClient ()
51      {
52          setDefaultPort(DEFAULT_PORT);
53      }
54  
55      /**
56       * Retrieves the time string from the server and returns it.  The
57       * server will have closed the connection at this point, so you should
58       * call
59       * {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
60       * after calling this method.  To retrieve another time, you must
61       * initiate another connection with
62       * {@link org.apache.commons.net.SocketClient#connect  connect }
63       * before calling <code> getTime() </code> again.
64       * <p>
65       * @return The time string retrieved from the server.
66       * @exception IOException  If an error occurs while fetching the time string.
67       */
68      public String getTime() throws IOException
69      {
70          int read;
71          StringBuilder result = new StringBuilder(__buffer.length);
72          BufferedReader reader;
73  
74          reader = new BufferedReader(new InputStreamReader(_input_, getCharsetName())); // Java 1.6 can use getCharset()
75  
76          while (true)
77          {
78              read = reader.read(__buffer, 0, __buffer.length);
79              if (read <= 0) {
80                  break;
81              }
82              result.append(__buffer, 0, read);
83          }
84  
85          return result.toString();
86      }
87  
88  }
89