/* 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.acl.AclEntry;

 import org.acegisecurity.acl.AclManager;

 import org.acegisecurity.acl.basic.BasicAclEntry;

 import org.acegisecurity.acl.basic.SimpleAclEntry;

 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.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 AclManager}.</p>

  *  <p>The <code>AclManager</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.

  * This class is designed to process {@link AclEntry}s that are subclasses of {@link

  * org.acegisecurity.acl.basic.BasicAclEntry} only. Generally these are obtained by using the {@link

  * org.acegisecurity.acl.basic.BasicAclProvider}.</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>AclManager</code> and ensure the

  * principal is {@link org.acegisecurity.acl.basic.BasicAclEntry#isPermitted(int)} for at least one of the {@link

  * #requirePermission}s for each <code>Collection</code> element. If the principal does not have at least one of the

  * permissions, 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>SimpleAclEntry.READ</code>. These are also the defaults.</p>

  *  <p>The <code>AclManager</code> is allowed to return any implementations of <code>AclEntry</code> it wishes.

  * However, this provider will only be able to validate against <code>BasicAclEntry</code>s, and thus a

  * <code>Collection</code> element will be filtered from the resulting <code>Collection</code> if no

  * <code>AclEntry</code> is of type <code>BasicAclEntry</code>.</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: BasicAclEntryAfterInvocationCollectionFilteringProvider.java 1784 2007-02-24 21:00:24Z luke_t $

  */

 public class BasicAclEntryAfterInvocationCollectionFilteringProvider implements AfterInvocationProvider,

     InitializingBean {

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

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

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

     private AclManager aclManager;

     private Class processDomainObjectClass = Object.class;

     private String processConfigAttribute = "AFTER_ACL_COLLECTION_READ";

     private int[] requirePermission = {SimpleAclEntry.READ};

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

     public void afterPropertiesSet() throws Exception {

         Assert.notNull(processConfigAttribute, "A processConfigAttribute is mandatory");

         Assert.notNull(aclManager, "An aclManager is mandatory");

         if ((requirePermission == null) || (requirePermission.length == 0)) {

             throw new IllegalArgumentException("One or more requirePermission entries is mandatory");

         }

     }

     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 (!processDomainObjectClass.isAssignableFrom(domainObject.getClass())) {

                         hasPermission = true;

                     } else {

                         AclEntry[] acls = aclManager.getAcls(domainObject, authentication);

                         if ((acls != null) && (acls.length != 0)) {

                             for (int i = 0; i < acls.length; i++) {

                                 // Locate processable AclEntrys

                                 if (acls[i] instanceof BasicAclEntry) {

                                     BasicAclEntry processableAcl = (BasicAclEntry) acls[i];

                                     // See if principal has any of the required permissions

                                     for (int y = 0; y < requirePermission.length; y++) {

                                         if (processableAcl.isPermitted(requirePermission[y])) {

                                             hasPermission = true;

                                             if (logger.isDebugEnabled()) {

                                                 logger.debug("Principal is authorised for element: " + domainObject

                                                     + " due to ACL: " + processableAcl.toString());

                                             }

                                         }

                                     }

                                 }

                             }

                         }

                         if (!hasPermission) {

                             filterer.remove(domainObject);

                             if (logger.isDebugEnabled()) {

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

                             }

                         }

                     }

                 }

                 return filterer.getFilteredObject();

             }

         }

         return returnedObject;

     }

     public AclManager getAclManager() {

         return aclManager;

     }

     public String getProcessConfigAttribute() {

         return processConfigAttribute;

     }

     public int[] getRequirePermission() {

         return requirePermission;

     }

     public void setAclManager(AclManager aclManager) {

         this.aclManager = aclManager;

     }

     public void setProcessConfigAttribute(String processConfigAttribute) {

         this.processConfigAttribute = processConfigAttribute;

     }

     public void setProcessDomainObjectClass(Class processDomainObjectClass) {

         Assert.notNull(processDomainObjectClass, "processDomainObjectClass cannot be set to null");

         this.processDomainObjectClass = processDomainObjectClass;

     }

     public void setRequirePermission(int[] requirePermission) {

         this.requirePermission = requirePermission;

     }

     /**

      * Allow setting permissions with String literals instead of integers as {@link

      * #setRequirePermission(int[])}

      *

      * @param requiredPermissions permission literals

      *

      * @see SimpleAclEntry#parsePermissions(String[]) for valid values

      */

     public void setRequirePermissionFromString(String[] requiredPermissions) {

         setRequirePermission(SimpleAclEntry.parsePermissions(requiredPermissions));

     }

     public boolean supports(ConfigAttribute attribute) {

         if ((attribute.getAttribute() != null) && attribute.getAttribute().equals(getProcessConfigAttribute())) {

             return true;

         } else {

             return false;

         }

     }

     /**

      * This implementation supports any type of class, because it does not query the presented secure object.

      *

      * @param clazz the secure object

      *

      * @return always <code>true</code>

      */

     public boolean supports(Class clazz) {

         return true;

     }

 }