/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/conn/routing/BasicRouteDirector.java $
* $Revision: 620255 $
* $Date: 2008-02-10 02:23:55 -0800 (Sun, 10 Feb 2008) $
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.conn.routing;
/**
* Basic implementation of an {@link HttpRouteDirector HttpRouteDirector}.
* This implementation is stateless and therefore thread-safe.
*
* @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
*
*
* <!-- empty lines to avoid svn diff problems -->
* @version $Revision: 620255 $
*
* @since 4.0
*/
public class BasicRouteDirector implements HttpRouteDirector {
// public default constructor
/**
* Provides the next step.
*
* @param plan the planned route
* @param fact the currently established route, or
* <code>null</code> if nothing is established
*
* @return one of the constants defined in this class, indicating
* either the next step to perform, or success, or failure.
* 0 is for success, a negative value for failure.
*/
public int nextStep(RouteInfo plan, RouteInfo fact) {
if (plan == null) {
throw new IllegalArgumentException
("Planned route may not be null.");
}
int step = UNREACHABLE;
if ((fact == null) || (fact.getHopCount() < 1))
step = firstStep(plan);
else if (plan.getHopCount() > 1)
step = proxiedStep(plan, fact);
else
step = directStep(plan, fact);
return step;
} // nextStep
/**
* Determines the first step to establish a route.
*
* @param plan the planned route
*
* @return the first step
*/
protected int firstStep(RouteInfo plan) {
return (plan.getHopCount() > 1) ?
CONNECT_PROXY : CONNECT_TARGET;
}
/**
* Determines the next step to establish a direct connection.
*
* @param plan the planned route
* @param fact the currently established route
*
* @return one of the constants defined in this class, indicating
* either the next step to perform, or success, or failure
*/
protected int directStep(RouteInfo plan, RouteInfo fact) {
if (fact.getHopCount() > 1)
return UNREACHABLE;
if (!plan.getTargetHost().equals(fact.getTargetHost()))
return UNREACHABLE;
// If the security is too low, we could now suggest to layer
// a secure protocol on the direct connection. Layering on direct
// connections has not been supported in HttpClient 3.x, we don't
// consider it here until there is a real-life use case for it.
// Should we tolerate if security is better than planned?
// (plan.isSecure() && !fact.isSecure())
if (plan.isSecure() != fact.isSecure())
return UNREACHABLE;
// Local address has to match only if the plan specifies one.
if ((plan.getLocalAddress() != null) &&
!plan.getLocalAddress().equals(fact.getLocalAddress())
)
return UNREACHABLE;
return COMPLETE;
}
/**
* Determines the next step to establish a connection via proxy.
*
* @param plan the planned route
* @param fact the currently established route
*
* @return one of the constants defined in this class, indicating
* either the next step to perform, or success, or failure
*/
protected int proxiedStep(RouteInfo plan, RouteInfo fact) {
if (fact.getHopCount() <= 1)
return UNREACHABLE;
if (!plan.getTargetHost().equals(fact.getTargetHost()))
return UNREACHABLE;
final int phc = plan.getHopCount();
final int fhc = fact.getHopCount();
if (phc < fhc)
return UNREACHABLE;
for (int i=0; i<fhc-1; i++) {
if (!plan.getHopTarget(i).equals(fact.getHopTarget(i)))
return UNREACHABLE;
}
// now we know that the target matches and proxies so far are the same
if (phc > fhc)
return TUNNEL_PROXY; // need to extend the proxy chain
// proxy chain and target are the same, check tunnelling and layering
if ((fact.isTunnelled() && !plan.isTunnelled()) ||
(fact.isLayered() && !plan.isLayered()))
return UNREACHABLE;
if (plan.isTunnelled() && !fact.isTunnelled())
return TUNNEL_TARGET;
if (plan.isLayered() && !fact.isLayered())
return LAYER_PROTOCOL;
// tunnel and layering are the same, remains to check the security
// Should we tolerate if security is better than planned?
// (plan.isSecure() && !fact.isSecure())
if (plan.isSecure() != fact.isSecure())
return UNREACHABLE;
return COMPLETE;
}
} // class BasicRouteDirector