/* 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.acegisecurity.intercept.web.FilterInvocationDefinitionSource;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.springframework.beans.factory.InitializingBean;

 import org.springframework.util.Assert;

 import java.io.IOException;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.Set;

 import javax.servlet.Filter;

 import javax.servlet.FilterChain;

 import javax.servlet.FilterConfig;

 import javax.servlet.ServletException;

 import javax.servlet.ServletRequest;

 import javax.servlet.ServletResponse;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 /**

  * Ensures a web request is delivered over the required channel.<p>Internally uses a {@link FilterInvocation} to

  * represent the request, so that the <code>FilterInvocation</code>-related property editors and lookup classes can be

  * used.</p>

  *  <P>Delegates the actual channel security decisions and necessary actions to the configured {@link

  * ChannelDecisionManager}. If a response is committed by the <code>ChannelDecisionManager</code>, the filter chain

  * will not proceed.</p>

  *  <P><B>Do not use this class directly.</B> Instead configure <code>web.xml</code> to use the {@link

  * org.acegisecurity.util.FilterToBeanProxy}.</p>

  *

  * @author Ben Alex

  * @version $Id: ChannelProcessingFilter.java 1784 2007-02-24 21:00:24Z luke_t $

  */

 public class ChannelProcessingFilter implements InitializingBean, Filter {

     //~ Static fields/initializers =====================================================================================

     private static final Log logger = LogFactory.getLog(ChannelProcessingFilter.class);

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

     private ChannelDecisionManager channelDecisionManager;

     private FilterInvocationDefinitionSource filterInvocationDefinitionSource;

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

     public void afterPropertiesSet() throws Exception {

         Assert.notNull(filterInvocationDefinitionSource, "filterInvocationDefinitionSource must be specified");

         Assert.notNull(channelDecisionManager, "channelDecisionManager must be specified");

         Iterator iter = this.filterInvocationDefinitionSource.getConfigAttributeDefinitions();

         if (iter == null) {

             if (logger.isWarnEnabled()) {

                 logger.warn("Could not validate configuration attributes as the FilterInvocationDefinitionSource did "

                         + "not return a ConfigAttributeDefinition Iterator");

             }

             return;

         }

         Set set = new HashSet();

         while (iter.hasNext()) {

             ConfigAttributeDefinition def = (ConfigAttributeDefinition) iter.next();

             Iterator attributes = def.getConfigAttributes();

             while (attributes.hasNext()) {

                 ConfigAttribute attr = (ConfigAttribute) attributes.next();

                 if (!this.channelDecisionManager.supports(attr)) {

                     set.add(attr);

                 }

             }

         }

         if (set.size() == 0) {

             if (logger.isInfoEnabled()) {

                 logger.info("Validated configuration attributes");

             }

         } else {

             throw new IllegalArgumentException("Unsupported configuration attributes: " + set.toString());

         }

     }

     public void destroy() {}

     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)

         throws IOException, ServletException {

         if (!(request instanceof HttpServletRequest)) {

             throw new ServletException("HttpServletRequest required");

         }

         if (!(response instanceof HttpServletResponse)) {

             throw new ServletException("HttpServletResponse required");

         }

         FilterInvocation fi = new FilterInvocation(request, response, chain);

         ConfigAttributeDefinition attr = this.filterInvocationDefinitionSource.getAttributes(fi);

         if (attr != null) {

             if (logger.isDebugEnabled()) {

                 logger.debug("Request: " + fi.toString() + "; ConfigAttributes: " + attr.toString());

             }

             channelDecisionManager.decide(fi, attr);

             if (fi.getResponse().isCommitted()) {

                 return;

             }

         }

         chain.doFilter(request, response);

     }

     public ChannelDecisionManager getChannelDecisionManager() {

         return channelDecisionManager;

     }

     public FilterInvocationDefinitionSource getFilterInvocationDefinitionSource() {

         return filterInvocationDefinitionSource;

     }

     public void init(FilterConfig filterConfig) throws ServletException {}

     public void setChannelDecisionManager(ChannelDecisionManager channelDecisionManager) {

         this.channelDecisionManager = channelDecisionManager;

     }

     public void setFilterInvocationDefinitionSource(FilterInvocationDefinitionSource filterInvocationDefinitionSource) {

         this.filterInvocationDefinitionSource = filterInvocationDefinitionSource;

     }

 }