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.hc.client5.http.routing; 29 30 import org.apache.hc.client5.http.RouteInfo; 31 import org.apache.hc.core5.annotation.Contract; 32 import org.apache.hc.core5.annotation.ThreadingBehavior; 33 34 /** 35 * Provides directions on establishing a route. 36 * Implementations of this interface compare a planned route with 37 * a tracked route and indicate the next step required. 38 * 39 * @since 4.0 40 */ 41 @Contract(threading = ThreadingBehavior.STATELESS) 42 public interface HttpRouteDirector { 43 44 /** Indicates that the route can not be established at all. */ 45 int UNREACHABLE = -1; 46 47 /** Indicates that the route is complete. */ 48 int COMPLETE = 0; 49 50 /** Step: open connection to target. */ 51 int CONNECT_TARGET = 1; 52 53 /** Step: open connection to proxy. */ 54 int CONNECT_PROXY = 2; 55 56 /** Step: tunnel through proxy to target. */ 57 int TUNNEL_TARGET = 3; 58 59 /** Step: tunnel through proxy to other proxy. */ 60 int TUNNEL_PROXY = 4; 61 62 /** Step: layer protocol (over tunnel). */ 63 int LAYER_PROTOCOL = 5; 64 65 66 /** 67 * Provides the next step. 68 * 69 * @param plan the planned route 70 * @param fact the currently established route, or 71 * {@code null} if nothing is established 72 * 73 * @return one of the constants defined in this interface, indicating 74 * either the next step to perform, or success, or failure. 75 * 0 is for success, a negative value for failure. 76 */ 77 int nextStep(RouteInfo plan, RouteInfo fact); 78 79 }