/* 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.afterinvocation;

 import org.acegisecurity.AccessDeniedException;

 import org.acegisecurity.AfterInvocationManager;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.ConfigAttribute;

 import org.acegisecurity.ConfigAttributeDefinition;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.springframework.beans.factory.InitializingBean;

 import java.util.Iterator;

 import java.util.List;

 /**

  * Provider-based implementation of {@link AfterInvocationManager}.<p>Handles configuration of a bean context

  * defined list of  {@link AfterInvocationProvider}s.</p>

  *  <p>Every <code>AfterInvocationProvider</code> will be polled when the {@link #decide(Authentication, Object,

  * ConfigAttributeDefinition, Object)} method is called. The <code>Object</code> returned from each provider will be

  * presented to the successive provider for processing. This means each provider <b>must</b> ensure they return the

  * <code>Object</code>, even if they are not interested in the "after invocation" decision (perhaps as the secure

  * object invocation did not include a configuration attribute a given provider is configured to respond to).</p>

  *

  * @author Ben Alex

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

  */

 public class AfterInvocationProviderManager implements AfterInvocationManager, InitializingBean {

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

     protected static final Log logger = LogFactory.getLog(AfterInvocationProviderManager.class);

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

     private List providers;

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

     public void afterPropertiesSet() throws Exception {

         checkIfValidList(this.providers);

     }

     private void checkIfValidList(List listToCheck) {

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

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

         }

     }

     public Object decide(Authentication authentication, Object object, ConfigAttributeDefinition config,

         Object returnedObject) throws AccessDeniedException {

         Iterator iter = this.providers.iterator();

         Object result = returnedObject;

         while (iter.hasNext()) {

             AfterInvocationProvider provider = (AfterInvocationProvider) iter.next();

             result = provider.decide(authentication, object, config, result);

         }

         return result;

     }

     public List getProviders() {

         return this.providers;

     }

     public void setProviders(List newList) {

         checkIfValidList(newList);

         Iterator iter = newList.iterator();

         while (iter.hasNext()) {

             Object currentObject = null;

             try {

                 currentObject = iter.next();

                 AfterInvocationProvider attemptToCast = (AfterInvocationProvider) currentObject;

             } catch (ClassCastException cce) {

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

                     + " must implement AfterInvocationProvider");

             }

         }

         this.providers = newList;

     }

     public boolean supports(ConfigAttribute attribute) {

         Iterator iter = this.providers.iterator();

         while (iter.hasNext()) {

             AfterInvocationProvider provider = (AfterInvocationProvider) iter.next();

             if (logger.isDebugEnabled()) {

                 logger.debug("Evaluating " + attribute + " against " + provider);

             }

             if (provider.supports(attribute)) {

                 return true;

             }

         }

         return false;

     }

     /**

      * Iterates through all <code>AfterInvocationProvider</code>s and ensures each can support the presented

      * class.<p>If one or more providers cannot support the presented class, <code>false</code> is returned.</p>

      *

      * @param clazz the secure object class being queries

      *

      * @return if the <code>AfterInvocationProviderManager</code> can support the secure object class, which requires

      *         every one of its <code>AfterInvocationProvider</code>s to support the secure object class

      */

     public boolean supports(Class clazz) {

         Iterator iter = this.providers.iterator();

         while (iter.hasNext()) {

             AfterInvocationProvider provider = (AfterInvocationProvider) iter.next();

             if (!provider.supports(clazz)) {

                 return false;

             }

         }

         return true;

     }

 }