    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}