/lib/src/org/apache/http/conn/routing/HttpRouteDirector.java

 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
28package org.apache.http.conn.routing;
29
30/**
31 * Provides directions on establishing a route.
32 * Implementations of this interface compare a planned route with
33 * a tracked route and indicate the next step required.
34 *
35 * @since 4.0
36 */
37public interface HttpRouteDirector {
38
39    /** Indicates that the route can not be established at all. */
40    public final static int UNREACHABLE = -1;
41
42    /** Indicates that the route is complete. */
43    public final static int COMPLETE = 0;
44
45    /** Step: open connection to target. */
46    public final static int CONNECT_TARGET = 1;
47
48    /** Step: open connection to proxy. */
49    public final static int CONNECT_PROXY = 2;
50
51    /** Step: tunnel through proxy to target. */
52    public final static int TUNNEL_TARGET = 3;
53
54    /** Step: tunnel through proxy to other proxy. */
55    public final static int TUNNEL_PROXY = 4;
56
57    /** Step: layer protocol (over tunnel). */
58    public final static int LAYER_PROTOCOL = 5;
59
60
61    /**
62     * Provides the next step.
63     *
64     * @param plan      the planned route
65     * @param fact      the currently established route, or
66     *                  <code>null</code> if nothing is established
67     *
68     * @return  one of the constants defined in this interface, indicating
69     *          either the next step to perform, or success, or failure.
70     *          0 is for success, a negative value for failure.
71     */
72    public int nextStep(RouteInfo plan, RouteInfo fact);
73
74}