1 /* 2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/conn/routing/BasicRouteDirector.java $ 3 * $Revision: 620255 $ 4 * $Date: 2008-02-10 02:23:55 -0800 (Sun, 10 Feb 2008) $ 5 * 6 * ==================================================================== 7 * Licensed to the Apache Software Foundation (ASF) under one 8 * or more contributor license agreements. See the NOTICE file 9 * distributed with this work for additional information 10 * regarding copyright ownership. The ASF licenses this file 11 * to you under the Apache License, Version 2.0 (the 12 * "License"); you may not use this file except in compliance 13 * with the License. You may obtain a copy of the License at 14 * 15 * http://www.apache.org/licenses/LICENSE-2.0 16 * 17 * Unless required by applicable law or agreed to in writing, 18 * software distributed under the License is distributed on an 19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 20 * KIND, either express or implied. See the License for the 21 * specific language governing permissions and limitations 22 * under the License. 23 * ==================================================================== 24 * 25 * This software consists of voluntary contributions made by many 26 * individuals on behalf of the Apache Software Foundation. For more 27 * information on the Apache Software Foundation, please see 28 * <http://www.apache.org/>. 29 * 30 */ 31 32 package org.apache.http.conn.routing; 33 34 35 36 /** 37 * Basic implementation of an {@link HttpRouteDirector HttpRouteDirector}. 38 * This implementation is stateless and therefore thread-safe. 39 * 40 * @author <a href="mailto:rolandw at apache.org">Roland Weber</a> 41 * 42 * 43 * <!-- empty lines to avoid svn diff problems --> 44 * @version $Revision: 620255 $ 45 * 46 * @since 4.0 47 */ 48 public class BasicRouteDirector implements HttpRouteDirector { 49 50 // public default constructor 51 52 53 /** 54 * Provides the next step. 55 * 56 * @param plan the planned route 57 * @param fact the currently established route, or 58 * <code>null</code> if nothing is established 59 * 60 * @return one of the constants defined in this class, indicating 61 * either the next step to perform, or success, or failure. 62 * 0 is for success, a negative value for failure. 63 */ nextStep(RouteInfo plan, RouteInfo fact)64 public int nextStep(RouteInfo plan, RouteInfo fact) { 65 if (plan == null) { 66 throw new IllegalArgumentException 67 ("Planned route may not be null."); 68 } 69 70 int step = UNREACHABLE; 71 72 if ((fact == null) || (fact.getHopCount() < 1)) 73 step = firstStep(plan); 74 else if (plan.getHopCount() > 1) 75 step = proxiedStep(plan, fact); 76 else 77 step = directStep(plan, fact); 78 79 return step; 80 81 } // nextStep 82 83 84 /** 85 * Determines the first step to establish a route. 86 * 87 * @param plan the planned route 88 * 89 * @return the first step 90 */ firstStep(RouteInfo plan)91 protected int firstStep(RouteInfo plan) { 92 93 return (plan.getHopCount() > 1) ? 94 CONNECT_PROXY : CONNECT_TARGET; 95 } 96 97 98 /** 99 * Determines the next step to establish a direct connection. 100 * 101 * @param plan the planned route 102 * @param fact the currently established route 103 * 104 * @return one of the constants defined in this class, indicating 105 * either the next step to perform, or success, or failure 106 */ directStep(RouteInfo plan, RouteInfo fact)107 protected int directStep(RouteInfo plan, RouteInfo fact) { 108 109 if (fact.getHopCount() > 1) 110 return UNREACHABLE; 111 if (!plan.getTargetHost().equals(fact.getTargetHost())) 112 return UNREACHABLE; 113 // If the security is too low, we could now suggest to layer 114 // a secure protocol on the direct connection. Layering on direct 115 // connections has not been supported in HttpClient 3.x, we don't 116 // consider it here until there is a real-life use case for it. 117 118 // Should we tolerate if security is better than planned? 119 // (plan.isSecure() && !fact.isSecure()) 120 if (plan.isSecure() != fact.isSecure()) 121 return UNREACHABLE; 122 123 // Local address has to match only if the plan specifies one. 124 if ((plan.getLocalAddress() != null) && 125 !plan.getLocalAddress().equals(fact.getLocalAddress()) 126 ) 127 return UNREACHABLE; 128 129 return COMPLETE; 130 } 131 132 133 /** 134 * Determines the next step to establish a connection via proxy. 135 * 136 * @param plan the planned route 137 * @param fact the currently established route 138 * 139 * @return one of the constants defined in this class, indicating 140 * either the next step to perform, or success, or failure 141 */ proxiedStep(RouteInfo plan, RouteInfo fact)142 protected int proxiedStep(RouteInfo plan, RouteInfo fact) { 143 144 if (fact.getHopCount() <= 1) 145 return UNREACHABLE; 146 if (!plan.getTargetHost().equals(fact.getTargetHost())) 147 return UNREACHABLE; 148 final int phc = plan.getHopCount(); 149 final int fhc = fact.getHopCount(); 150 if (phc < fhc) 151 return UNREACHABLE; 152 153 for (int i=0; i<fhc-1; i++) { 154 if (!plan.getHopTarget(i).equals(fact.getHopTarget(i))) 155 return UNREACHABLE; 156 } 157 // now we know that the target matches and proxies so far are the same 158 if (phc > fhc) 159 return TUNNEL_PROXY; // need to extend the proxy chain 160 161 // proxy chain and target are the same, check tunnelling and layering 162 if ((fact.isTunnelled() && !plan.isTunnelled()) || 163 (fact.isLayered() && !plan.isLayered())) 164 return UNREACHABLE; 165 166 if (plan.isTunnelled() && !fact.isTunnelled()) 167 return TUNNEL_TARGET; 168 if (plan.isLayered() && !fact.isLayered()) 169 return LAYER_PROTOCOL; 170 171 // tunnel and layering are the same, remains to check the security 172 // Should we tolerate if security is better than planned? 173 // (plan.isSecure() && !fact.isSecure()) 174 if (plan.isSecure() != fact.isSecure()) 175 return UNREACHABLE; 176 177 return COMPLETE; 178 } 179 180 181 } // class BasicRouteDirector 182