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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.smtp;
19  
20  import java.util.Enumeration;
21  import java.util.Vector;
22  
23  /***
24   * A class used to represent forward and reverse relay paths.  The
25   * SMTP MAIL command requires a reverse relay path while the SMTP RCPT
26   * command requires a forward relay path.  See RFC 821 for more details.
27   * In general, you will not have to deal with relay paths.
28   *
29   * @see SMTPClient
30   ***/
31  
32  public final class RelayPath
33  {
34      Vector<String> _path;
35      String _emailAddress;
36  
37      /***
38       * Create a relay path with the specified email address as the ultimate
39       * destination.
40       * <p>
41       * @param emailAddress The destination email address.
42       ***/
43      public RelayPath(String emailAddress)
44      {
45          _path = new Vector<String>();
46          _emailAddress = emailAddress;
47      }
48  
49      /***
50       * Add a mail relay host to the relay path.  Hosts are added left to
51       * right.  For example, the following will create the path
52       * <code><b> &lt; @bar.com,@foo.com:foobar@foo.com &gt; </b></code>
53       * <pre>
54       * path = new RelayPath("foobar@foo.com");
55       * path.addRelay("bar.com");
56       * path.addRelay("foo.com");
57       * </pre>
58       * <p>
59       * @param hostname The host to add to the relay path.
60       ***/
61      public void addRelay(String hostname)
62      {
63          _path.addElement(hostname);
64      }
65  
66      /***
67       * Return the properly formatted string representation of the relay path.
68       * <p>
69       * @return The properly formatted string representation of the relay path.
70       ***/
71      @Override
72      public String toString()
73      {
74          StringBuilder buffer = new StringBuilder();
75          Enumeration<String> hosts;
76  
77          buffer.append('<');
78  
79          hosts = _path.elements();
80  
81          if (hosts.hasMoreElements())
82          {
83              buffer.append('@');
84              buffer.append(hosts.nextElement());
85  
86              while (hosts.hasMoreElements())
87              {
88                  buffer.append(",@");
89                  buffer.append(hosts.nextElement());
90              }
91              buffer.append(':');
92          }
93  
94          buffer.append(_emailAddress);
95          buffer.append('>');
96  
97          return buffer.toString();
98      }
99  
100 }