1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.http.conn.routing;
29
30 import java.net.InetAddress;
31
32 import org.apache.http.HttpHost;
33
34 /**
35 * Read-only interface for route information.
36 *
37 * @since 4.0
38 */
39 public interface RouteInfo {
40
41 /**
42 * The tunnelling type of a route.
43 * Plain routes are established by connecting to the target or
44 * the first proxy.
45 * Tunnelled routes are established by connecting to the first proxy
46 * and tunnelling through all proxies to the target.
47 * Routes without a proxy cannot be tunnelled.
48 */
49 public enum TunnelType { PLAIN, TUNNELLED }
50
51 /**
52 * The layering type of a route.
53 * Plain routes are established by connecting or tunnelling.
54 * Layered routes are established by layering a protocol such as TLS/SSL
55 * over an existing connection.
56 * Protocols can only be layered over a tunnel to the target, or
57 * or over a direct connection without proxies.
58 * <p>
59 * Layering a protocol
60 * over a direct connection makes little sense, since the connection
61 * could be established with the new protocol in the first place.
62 * But we don't want to exclude that use case.
63 * </p>
64 */
65 public enum LayerType { PLAIN, LAYERED }
66
67 /**
68 * Obtains the target host.
69 *
70 * @return the target host
71 */
72 HttpHost getTargetHost();
73
74 /**
75 * Obtains the local address to connect from.
76 *
77 * @return the local address,
78 * or {@code null}
79 */
80 InetAddress getLocalAddress();
81
82 /**
83 * Obtains the number of hops in this route.
84 * A direct route has one hop. A route through a proxy has two hops.
85 * A route through a chain of <i>n</i> proxies has <i>n+1</i> hops.
86 *
87 * @return the number of hops in this route
88 */
89 int getHopCount();
90
91 /**
92 * Obtains the target of a hop in this route.
93 * The target of the last hop is the {@link #getTargetHost target host},
94 * the target of previous hops is the respective proxy in the chain.
95 * For a route through exactly one proxy, target of hop 0 is the proxy
96 * and target of hop 1 is the target host.
97 *
98 * @param hop index of the hop for which to get the target,
99 * 0 for first
100 *
101 * @return the target of the given hop
102 *
103 * @throws IllegalArgumentException
104 * if the argument is negative or not less than
105 * {@link #getHopCount getHopCount()}
106 */
107 HttpHost getHopTarget(int hop);
108
109 /**
110 * Obtains the first proxy host.
111 *
112 * @return the first proxy in the proxy chain, or
113 * {@code null} if this route is direct
114 */
115 HttpHost getProxyHost();
116
117 /**
118 * Obtains the tunnel type of this route.
119 * If there is a proxy chain, only end-to-end tunnels are considered.
120 *
121 * @return the tunnelling type
122 */
123 TunnelType getTunnelType();
124
125 /**
126 * Checks whether this route is tunnelled through a proxy.
127 * If there is a proxy chain, only end-to-end tunnels are considered.
128 *
129 * @return {@code true} if tunnelled end-to-end through at least
130 * one proxy,
131 * {@code false} otherwise
132 */
133 boolean isTunnelled();
134
135 /**
136 * Obtains the layering type of this route.
137 * In the presence of proxies, only layering over an end-to-end tunnel
138 * is considered.
139 *
140 * @return the layering type
141 */
142 LayerType getLayerType();
143
144 /**
145 * Checks whether this route includes a layered protocol.
146 * In the presence of proxies, only layering over an end-to-end tunnel
147 * is considered.
148 *
149 * @return {@code true} if layered,
150 * {@code false} otherwise
151 */
152 boolean isLayered();
153
154 /**
155 * Checks whether this route is secure.
156 *
157 * @return {@code true} if secure,
158 * {@code false} otherwise
159 */
160 boolean isSecure();
161
162 }