001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.conn.routing; 029 030/** 031 * Provides directions on establishing a route. 032 * Implementations of this interface compare a planned route with 033 * a tracked route and indicate the next step required. 034 * 035 * @since 4.0 036 */ 037public interface HttpRouteDirector { 038 039 /** Indicates that the route can not be established at all. */ 040 public final static int UNREACHABLE = -1; 041 042 /** Indicates that the route is complete. */ 043 public final static int COMPLETE = 0; 044 045 /** Step: open connection to target. */ 046 public final static int CONNECT_TARGET = 1; 047 048 /** Step: open connection to proxy. */ 049 public final static int CONNECT_PROXY = 2; 050 051 /** Step: tunnel through proxy to target. */ 052 public final static int TUNNEL_TARGET = 3; 053 054 /** Step: tunnel through proxy to other proxy. */ 055 public final static int TUNNEL_PROXY = 4; 056 057 /** Step: layer protocol (over tunnel). */ 058 public final static int LAYER_PROTOCOL = 5; 059 060 061 /** 062 * Provides the next step. 063 * 064 * @param plan the planned route 065 * @param fact the currently established route, or 066 * {@code null} if nothing is established 067 * 068 * @return one of the constants defined in this interface, indicating 069 * either the next step to perform, or success, or failure. 070 * 0 is for success, a negative value for failure. 071 */ 072 public int nextStep(RouteInfo plan, RouteInfo fact); 073 074}