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 * @see SMTPClient
031 ***/
032
033public final class RelayPath
034{
035    Vector<String> _path;
036    String _emailAddress;
037
038    /***
039     * Create a relay path with the specified email address as the ultimate
040     * destination.
041     * <p>
042     * @param emailAddress The destination email address.
043     ***/
044    public RelayPath(String emailAddress)
045    {
046        _path = new Vector<String>();
047        _emailAddress = emailAddress;
048    }
049
050    /***
051     * Add a mail relay host to the relay path.  Hosts are added left to
052     * right.  For example, the following will create the path
053     * <code><b> &lt @bar.com,@foo.com:foobar@foo.com &gt </b></code>
054     * <pre>
055     * path = new RelayPath("foobar@foo.com");
056     * path.addRelay("bar.com");
057     * path.addRelay("foo.com");
058     * </pre>
059     * <p>
060     * @param hostname The host to add to the relay path.
061     ***/
062    public void addRelay(String hostname)
063    {
064        _path.addElement(hostname);
065    }
066
067    /***
068     * Return the properly formatted string representation of the relay path.
069     * <p>
070     * @return The properly formatted string representation of the relay path.
071     ***/
072    @Override
073    public String toString()
074    {
075        StringBuilder buffer = new StringBuilder();
076        Enumeration<String> hosts;
077
078        buffer.append('<');
079
080        hosts = _path.elements();
081
082        if (hosts.hasMoreElements())
083        {
084            buffer.append('@');
085            buffer.append(hosts.nextElement());
086
087            while (hosts.hasMoreElements())
088            {
089                buffer.append(",@");
090                buffer.append(hosts.nextElement());
091            }
092            buffer.append(':');
093        }
094
095        buffer.append(_emailAddress);
096        buffer.append('>');
097
098        return buffer.toString();
099    }
100
101}