/* 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.Authentication;

 import org.acegisecurity.AuthorizationServiceException;

 import org.acegisecurity.ConfigAttribute;

 import org.acegisecurity.ConfigAttributeDefinition;

 import org.acegisecurity.acls.AclService;

 import org.acegisecurity.acls.Permission;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import java.util.Collection;

 import java.util.Iterator;

 /**

  * <p>Given a <code>Collection</code> of domain object instances returned from a secure object invocation, remove

  * any <code>Collection</code> elements the principal does not have appropriate permission to access as defined by the

  * {@link AclService}.</p>

  *  <p>The <code>AclService</code> is used to retrieve the access control list (ACL) permissions associated with

  * each <code>Collection</code> domain object instance element for the current <code>Authentication</code> object.</p>

  *  <p>This after invocation provider will fire if any {@link ConfigAttribute#getAttribute()} matches the {@link

  * #processConfigAttribute}. The provider will then lookup the ACLs from the <code>AclService</code> and ensure the

  * principal is

  * {@link org.acegisecurity.acls.Acl#isGranted(org.acegisecurity.acls.Permission[],

  * org.acegisecurity.acls.sid.Sid[], boolean) Acl.isGranted(Permission[], Sid[], boolean)}

  * when presenting the {@link #requirePermission} array to that method.</p>

  *  <p>If the principal does not have permission, that element will not be included in the returned

  * <code>Collection</code>.</p>

  *  <p>Often users will setup a <code>BasicAclEntryAfterInvocationProvider</code> with a {@link

  * #processConfigAttribute} of <code>AFTER_ACL_COLLECTION_READ</code> and a {@link #requirePermission} of

  * <code>BasePermission.READ</code>. These are also the defaults.</p>

  *  <p>If the provided <code>returnObject</code> is <code>null</code>, a <code>null</code><code>Collection</code>

  * will be returned. If the provided <code>returnObject</code> is not a <code>Collection</code>, an {@link

  * AuthorizationServiceException} will be thrown.</p>

  *  <p>All comparisons and prefixes are case sensitive.</p>

  *

  * @author Ben Alex

  * @author Paulo Neves

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

  */

 public class AclEntryAfterInvocationCollectionFilteringProvider extends AbstractAclProvider {

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

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

     //~ Constructors ===================================================================================================

     public AclEntryAfterInvocationCollectionFilteringProvider(AclService aclService, Permission[] requirePermission) {

         super(aclService, "AFTER_ACL_COLLECTION_READ", requirePermission);

     }

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

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

         Object returnedObject) throws AccessDeniedException {

         Iterator iter = config.getConfigAttributes();

         while (iter.hasNext()) {

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

             if (this.supports(attr)) {

                 // Need to process the Collection for this invocation

                 if (returnedObject == null) {

                     if (logger.isDebugEnabled()) {

                         logger.debug("Return object is null, skipping");

                     }

                     return null;

                 }

                 Filterer filterer = null;

                 if (returnedObject instanceof Collection) {

                     Collection collection = (Collection) returnedObject;

                     filterer = new CollectionFilterer(collection);

                 } else if (returnedObject.getClass().isArray()) {

                     Object[] array = (Object[]) returnedObject;

                     filterer = new ArrayFilterer(array);

                 } else {

                     throw new AuthorizationServiceException("A Collection or an array (or null) was required as the "

                             + "returnedObject, but the returnedObject was: " + returnedObject);

                 }

                 // Locate unauthorised Collection elements

                 Iterator collectionIter = filterer.iterator();

                 while (collectionIter.hasNext()) {

                     Object domainObject = collectionIter.next();

                     boolean hasPermission = false;

                     if (domainObject == null) {

                         hasPermission = true;

                     } else if (!getProcessDomainObjectClass().isAssignableFrom(domainObject.getClass())) {

                         hasPermission = true;

                     } else {

                         hasPermission = hasPermission(authentication, domainObject);

                         if (!hasPermission) {

                             filterer.remove(domainObject);

                             if (logger.isDebugEnabled()) {

                                 logger.debug("Principal is NOT authorised for element: " + domainObject);

                             }

                         }

                     }

                 }

                 return filterer.getFilteredObject();

             }

         }

         return returnedObject;

     }

 }