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1   /*
2    * Copyright 2001-2005 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.net;
17  
18  import java.io.BufferedReader;
19  import java.io.IOException;
20  import java.io.InputStreamReader;
21  
22  /***
23   * The DaytimeTCPClient class is a TCP implementation of a client for the
24   * Daytime protocol described in RFC 867.  To use the class, merely
25   * establish a connection with
26   * {@link org.apache.commons.net.SocketClient#connect  connect }
27   * and call {@link #getTime  getTime() } to retrieve the daytime
28   * string, then
29   * call {@link org.apache.commons.net.SocketClient#disconnect  disconnect }
30   * to close the connection properly.
31   * <p>
32   * <p>
33   * @author Daniel F. Savarese
34   * @see DaytimeUDPClient
35   ***/
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 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          StringBuffer result = new StringBuffer(__buffer.length);
72          BufferedReader reader;
73  
74          reader = new BufferedReader(new InputStreamReader(_input_));
75  
76          while (true)
77          {
78              read = reader.read(__buffer, 0, __buffer.length);
79              if (read <= 0)
80                  break;
81              result.append(__buffer, 0, read);
82          }
83  
84          return result.toString();
85      }
86  
87  }
88