001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.net.smtp;
019
020import java.util.Enumeration;
021import java.util.Vector;
022
023/***
024 * A class used to represent forward and reverse relay paths.  The
025 * SMTP MAIL command requires a reverse relay path while the SMTP RCPT
026 * command requires a forward relay path.  See RFC 821 for more details.
027 * In general, you will not have to deal with relay paths.
028 * <p>
029 * <p>
030 * @author Daniel F. Savarese
031 * @see SMTPClient
032 ***/
033
034public final class RelayPath
035{
036    Vector<String> _path;
037    String _emailAddress;
038
039    /***
040     * Create a relay path with the specified email address as the ultimate
041     * destination.
042     * <p>
043     * @param emailAddress The destination email address.
044     ***/
045    public RelayPath(String emailAddress)
046    {
047        _path = new Vector<String>();
048        _emailAddress = emailAddress;
049    }
050
051    /***
052     * Add a mail relay host to the relay path.  Hosts are added left to
053     * right.  For example, the following will create the path
054     * <code><b> &lt @bar.com,@foo.com:foobar@foo.com &gt </b></code>
055     * <pre>
056     * path = new RelayPath("foobar@foo.com");
057     * path.addRelay("bar.com");
058     * path.addRelay("foo.com");
059     * </pre>
060     * <p>
061     * @param hostname The host to add to the relay path.
062     ***/
063    public void addRelay(String hostname)
064    {
065        _path.addElement(hostname);
066    }
067
068    /***
069     * Return the properly formatted string representation of the relay path.
070     * <p>
071     * @return The properly formatted string representation of the relay path.
072     ***/
073    @Override
074    public String toString()
075    {
076        StringBuffer buffer = new StringBuffer();
077        Enumeration<String> hosts;
078
079        buffer.append('<');
080
081        hosts = _path.elements();
082
083        if (hosts.hasMoreElements())
084        {
085            buffer.append('@');
086            buffer.append(hosts.nextElement());
087
088            while (hosts.hasMoreElements())
089            {
090                buffer.append(",@");
091                buffer.append(hosts.nextElement());
092            }
093            buffer.append(':');
094        }
095
096        buffer.append(_emailAddress);
097        buffer.append('>');
098
099        return buffer.toString();
100    }
101
102}