/* 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.AcegiMessageSource;

 import org.acegisecurity.Authentication;

 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.context.MessageSource;

 import org.springframework.context.MessageSourceAware;

 import org.springframework.context.i18n.LocaleContextHolder;

 import org.springframework.context.support.MessageSourceAccessor;

 import org.springframework.util.Assert;

 import java.util.Iterator;

 /**

  * <p>Given a domain object instance returned from a secure object invocation, ensures the principal has

  * appropriate permission as defined by the {@link AclManager}.</p>

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

  * domain object instance 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.</p>

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

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

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

  *  <p>If the principal does not have sufficient permissions, an <code>AccessDeniedException</code> will be thrown.</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 access will be

  * denied if no <code>AclEntry</code> is of type <code>BasicAclEntry</code>.</p>

  *  <p>If the provided <code>returnObject</code> is <code>null</code>, permission will always be granted and

  * <code>null</code> will be returned.</p>

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

  */

 public class BasicAclEntryAfterInvocationProvider implements AfterInvocationProvider, InitializingBean,

     MessageSourceAware {

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

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

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

     private AclManager aclManager;

     private Class processDomainObjectClass = Object.class;

     protected MessageSourceAccessor messages = AcegiMessageSource.getAccessor();

     private String processConfigAttribute = "AFTER_ACL_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");

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

         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 make an access decision on this invocation

                 if (returnedObject == null) {

                     // AclManager interface contract prohibits nulls

                     // As they have permission to null/nothing, grant access

                     if (logger.isDebugEnabled()) {

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

                     }

                     return null;

                 }

                 if (!processDomainObjectClass.isAssignableFrom(returnedObject.getClass())) {

                     if (logger.isDebugEnabled()) {

                         logger.debug("Return object is not applicable for this provider, skipping");

                     }

                     return null;

                 }

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

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

                     throw new AccessDeniedException(messages.getMessage(

                             "BasicAclEntryAfterInvocationProvider.noPermission",

                             new Object[] {authentication.getName(), returnedObject},

                             "Authentication {0} has NO permissions at all to the domain object {1}", LocaleContextHolder.getLocale()));

                 }

                 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])) {

                                 if (logger.isDebugEnabled()) {

                                     logger.debug("Principal DOES have permission to return object: " + returnedObject

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

                                 }

                                 return returnedObject;

                             }

                         }

                     }

                 }

                 // No permissions match

                 throw new AccessDeniedException(messages.getMessage(

                         "BasicAclEntryAfterInvocationProvider.insufficientPermission",

                         new Object[] {authentication.getName(), returnedObject},

                         "Authentication {0} has ACL permissions to the domain object, "

                         + "but not the required ACL permission to the domain object {1}", LocaleContextHolder.getLocale()));

             }

         }

         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 setMessageSource(MessageSource messageSource) {

         this.messages = new MessageSourceAccessor(messageSource);

     }

     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;

     }

 }