/* 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.vote;

 import java.util.Iterator;

 import java.util.List;

 import org.acegisecurity.AccessDecisionManager;

 import org.acegisecurity.AccessDeniedException;

 import org.acegisecurity.AcegiMessageSource;

 import org.acegisecurity.ConfigAttribute;

 import org.springframework.beans.factory.InitializingBean;

 import org.springframework.context.MessageSource;

 import org.springframework.context.MessageSourceAware;

 import org.springframework.context.support.MessageSourceAccessor;

 import org.springframework.util.Assert;

 /**

  * Abstract implementation of {@link AccessDecisionManager}.

  * <p/>

  * Handles configuration of a bean context defined list of

  * {@link AccessDecisionVoter}s and the access control behaviour if all voters

  * abstain from voting (defaults to deny access).

  * </p>

  */

 public abstract class AbstractAccessDecisionManager implements AccessDecisionManager, InitializingBean,

         MessageSourceAware {

     // ~ Instance fields

     // ================================================================================================

     private List decisionVoters;

     protected MessageSourceAccessor messages = AcegiMessageSource.getAccessor();

     private boolean allowIfAllAbstainDecisions = false;

     // ~ Methods

     // ========================================================================================================

     public void afterPropertiesSet() throws Exception {

         Assert.notEmpty(this.decisionVoters, "A list of AccessDecisionVoters is required");

         Assert.notNull(this.messages, "A message source must be set");

     }

     protected final void checkAllowIfAllAbstainDecisions() {

         if (!this.isAllowIfAllAbstainDecisions()) {

             throw new AccessDeniedException(messages.getMessage("AbstractAccessDecisionManager.accessDenied",

                     "Access is denied"));

         }

     }

     public List getDecisionVoters() {

         return this.decisionVoters;

     }

     public boolean isAllowIfAllAbstainDecisions() {

         return allowIfAllAbstainDecisions;

     }

     public void setAllowIfAllAbstainDecisions(boolean allowIfAllAbstainDecisions) {

         this.allowIfAllAbstainDecisions = allowIfAllAbstainDecisions;

     }

     public void setDecisionVoters(List newList) {

         Assert.notEmpty(newList);

         Iterator iter = newList.iterator();

         while (iter.hasNext()) {

             Object currentObject = iter.next();

             Assert.isInstanceOf(AccessDecisionVoter.class, currentObject, "AccessDecisionVoter " + currentObject.getClass().getName()

                     + " must implement AccessDecisionVoter");

         }

         this.decisionVoters = newList;

     }

     public void setMessageSource(MessageSource messageSource) {

         this.messages = new MessageSourceAccessor(messageSource);

     }

     public boolean supports(ConfigAttribute attribute) {

         Iterator iter = this.decisionVoters.iterator();

         while (iter.hasNext()) {

             AccessDecisionVoter voter = (AccessDecisionVoter) iter.next();

             if (voter.supports(attribute)) {

                 return true;

             }

         }

         return false;

     }

     /**

      * Iterates through all <code>AccessDecisionVoter</code>s and ensures

      * each can support the presented class.

      * <p/>

      * If one or more voters cannot support the presented class,

      * <code>false</code> is returned.

      * </p>

      *

      * @param clazz DOCUMENT ME!

      * @return DOCUMENT ME!

      */

     public boolean supports(Class clazz) {

         Iterator iter = this.decisionVoters.iterator();

         while (iter.hasNext()) {

             AccessDecisionVoter voter = (AccessDecisionVoter) iter.next();

             if (!voter.supports(clazz)) {

                 return false;

             }

         }

         return true;

     }

 }