Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.net.smtp; import java.util.Enumeration; import java.util.Vector; /*** * A class used to represent forward and reverse relay paths. The * SMTP MAIL command requires a reverse relay path while the SMTP RCPT * command requires a forward relay path. See RFC 821 for more details. * In general, you will not have to deal with relay paths. * <p> * <p> * @see SMTPClient ***/ public final class RelayPath { Vector<String> _path; String _emailAddress; /*** * Create a relay path with the specified email address as the ultimate * destination. * <p> * @param emailAddress The destination email address. ***/ public RelayPath(String emailAddress) { _path = new Vector<String>(); _emailAddress = emailAddress; } /*** * Add a mail relay host to the relay path. Hosts are added left to * right. For example, the following will create the path * <code><b> < @bar.com,@foo.com:foobar@foo.com > </b></code> * <pre> * path = new RelayPath("foobar@foo.com"); * path.addRelay("bar.com"); * path.addRelay("foo.com"); * </pre> * <p> * @param hostname The host to add to the relay path. ***/ public void addRelay(String hostname) { _path.addElement(hostname); } /*** * Return the properly formatted string representation of the relay path. * <p> * @return The properly formatted string representation of the relay path. ***/ @Override public String toString() { StringBuilder buffer = new StringBuilder(); Enumeration<String> hosts; buffer.append('<'); hosts = _path.elements(); if (hosts.hasMoreElements()) { buffer.append('@'); buffer.append(hosts.nextElement()); while (hosts.hasMoreElements()) { buffer.append(",@"); buffer.append(hosts.nextElement()); } buffer.append(':'); } buffer.append(_emailAddress); buffer.append('>'); return buffer.toString(); } }