/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited

  *

  * Licensed 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.

  */

 package org.acegisecurity.securechannel;

 import org.acegisecurity.ConfigAttribute;

 import org.acegisecurity.ConfigAttributeDefinition;

 import org.acegisecurity.intercept.web.FilterInvocation;

 import org.springframework.beans.factory.InitializingBean;

 import java.io.IOException;

 import java.util.Iterator;

 import java.util.List;

 import javax.servlet.ServletException;

 /**

  * Implementation of {@link ChannelDecisionManager}.<p>Iterates through each configured {@link ChannelProcessor}.

  * If a <code>ChannelProcessor</code> has any issue with the security of the request, it should cause a redirect,

  * exception or whatever other action is appropriate for the <code>ChannelProcessor</code> implementation.</p>

  *  <P>Once any response is committed (ie a redirect is written to the response object), the

  * <code>ChannelDecisionManagerImpl</code> will not iterate through any further <code>ChannelProcessor</code>s.</p>

  *

  * @author Ben Alex

  * @version $Id: ChannelDecisionManagerImpl.java 1496 2006-05-23 13:38:33Z benalex $

  */

 public class ChannelDecisionManagerImpl implements ChannelDecisionManager, InitializingBean {

     //~ Instance fields ================================================================================================

     private List channelProcessors;

     //~ Methods ========================================================================================================

     public void afterPropertiesSet() throws Exception {

         checkIfValidList(this.channelProcessors);

     }

     private void checkIfValidList(List listToCheck) {

         if ((listToCheck == null) || (listToCheck.size() == 0)) {

             throw new IllegalArgumentException("A list of ChannelProcessors is required");

         }

     }

     public void decide(FilterInvocation invocation, ConfigAttributeDefinition config)

         throws IOException, ServletException {

         Iterator iter = this.channelProcessors.iterator();

         while (iter.hasNext()) {

             ChannelProcessor processor = (ChannelProcessor) iter.next();

             processor.decide(invocation, config);

             if (invocation.getResponse().isCommitted()) {

                 break;

             }

         }

     }

     public List getChannelProcessors() {

         return this.channelProcessors;

     }

     public void setChannelProcessors(List newList) {

         checkIfValidList(newList);

         Iterator iter = newList.iterator();

         while (iter.hasNext()) {

             Object currentObject = null;

             try {

                 currentObject = iter.next();

                 ChannelProcessor attemptToCast = (ChannelProcessor) currentObject;

             } catch (ClassCastException cce) {

                 throw new IllegalArgumentException("ChannelProcessor " + currentObject.getClass().getName()

                     + " must implement ChannelProcessor");

             }

         }

         this.channelProcessors = newList;

     }

     public boolean supports(ConfigAttribute attribute) {

         Iterator iter = this.channelProcessors.iterator();

         while (iter.hasNext()) {

             ChannelProcessor processor = (ChannelProcessor) iter.next();

             if (processor.supports(attribute)) {

                 return true;

             }

         }

         return false;

     }

 }