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1   /* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
2    *
3    * Licensed under the Apache License, Version 2.0 (the "License");
4    * you may not use this file except in compliance with the License.
5    * You may obtain a copy of the License at
6    *
7    *     http://www.apache.org/licenses/LICENSE-2.0
8    *
9    * Unless required by applicable law or agreed to in writing, software
10   * distributed under the License is distributed on an "AS IS" BASIS,
11   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12   * See the License for the specific language governing permissions and
13   * limitations under the License.
14   */
15  package org.acegisecurity.afterinvocation;
16  
17  import org.acegisecurity.AccessDeniedException;
18  import org.acegisecurity.Authentication;
19  import org.acegisecurity.AuthorizationServiceException;
20  import org.acegisecurity.ConfigAttribute;
21  import org.acegisecurity.ConfigAttributeDefinition;
22  
23  import org.acegisecurity.acls.AclService;
24  import org.acegisecurity.acls.Permission;
25  
26  import org.apache.commons.logging.Log;
27  import org.apache.commons.logging.LogFactory;
28  
29  import java.util.Collection;
30  import java.util.Iterator;
31  
32  
33  /**
34   * <p>Given a <code>Collection</code> of domain object instances returned from a secure object invocation, remove
35   * any <code>Collection</code> elements the principal does not have appropriate permission to access as defined by the
36   * {@link AclService}.</p>
37   *  <p>The <code>AclService</code> is used to retrieve the access control list (ACL) permissions associated with
38   * each <code>Collection</code> domain object instance element for the current <code>Authentication</code> object.</p>
39   *  <p>This after invocation provider will fire if any {@link ConfigAttribute#getAttribute()} matches the {@link
40   * #processConfigAttribute}. The provider will then lookup the ACLs from the <code>AclService</code> and ensure the
41   * principal is
42   * {@link org.acegisecurity.acls.Acl#isGranted(org.acegisecurity.acls.Permission[],
43   * org.acegisecurity.acls.sid.Sid[], boolean) Acl.isGranted(Permission[], Sid[], boolean)}
44   * when presenting the {@link #requirePermission} array to that method.</p>
45   *  <p>If the principal does not have permission, that element will not be included in the returned
46   * <code>Collection</code>.</p>
47   *  <p>Often users will setup a <code>BasicAclEntryAfterInvocationProvider</code> with a {@link
48   * #processConfigAttribute} of <code>AFTER_ACL_COLLECTION_READ</code> and a {@link #requirePermission} of
49   * <code>BasePermission.READ</code>. These are also the defaults.</p>
50   *  <p>If the provided <code>returnObject</code> is <code>null</code>, a <code>null</code><code>Collection</code>
51   * will be returned. If the provided <code>returnObject</code> is not a <code>Collection</code>, an {@link
52   * AuthorizationServiceException} will be thrown.</p>
53   *  <p>All comparisons and prefixes are case sensitive.</p>
54   *
55   * @author Ben Alex
56   * @author Paulo Neves
57   * @version $Id: AclEntryAfterInvocationCollectionFilteringProvider.java 1784 2007-02-24 21:00:24Z luke_t $
58   */
59  public class AclEntryAfterInvocationCollectionFilteringProvider extends AbstractAclProvider {
60      //~ Static fields/initializers =====================================================================================
61  
62      protected static final Log logger = LogFactory.getLog(AclEntryAfterInvocationCollectionFilteringProvider.class);
63  
64      //~ Constructors ===================================================================================================
65  
66      public AclEntryAfterInvocationCollectionFilteringProvider(AclService aclService, Permission[] requirePermission) {
67          super(aclService, "AFTER_ACL_COLLECTION_READ", requirePermission);
68      }
69  
70      //~ Methods ========================================================================================================
71  
72      public Object decide(Authentication authentication, Object object, ConfigAttributeDefinition config,
73          Object returnedObject) throws AccessDeniedException {
74          Iterator iter = config.getConfigAttributes();
75  
76          while (iter.hasNext()) {
77              ConfigAttribute attr = (ConfigAttribute) iter.next();
78  
79              if (this.supports(attr)) {
80                  // Need to process the Collection for this invocation
81                  if (returnedObject == null) {
82                      if (logger.isDebugEnabled()) {
83                          logger.debug("Return object is null, skipping");
84                      }
85  
86                      return null;
87                  }
88  
89                  Filterer filterer = null;
90  
91                  if (returnedObject instanceof Collection) {
92                      Collection collection = (Collection) returnedObject;
93                      filterer = new CollectionFilterer(collection);
94                  } else if (returnedObject.getClass().isArray()) {
95                      Object[] array = (Object[]) returnedObject;
96                      filterer = new ArrayFilterer(array);
97                  } else {
98                      throw new AuthorizationServiceException("A Collection or an array (or null) was required as the "
99                              + "returnedObject, but the returnedObject was: " + returnedObject);
100                 }
101 
102                 // Locate unauthorised Collection elements
103                 Iterator collectionIter = filterer.iterator();
104 
105                 while (collectionIter.hasNext()) {
106                     Object domainObject = collectionIter.next();
107 
108                     boolean hasPermission = false;
109 
110                     if (domainObject == null) {
111                         hasPermission = true;
112                     } else if (!getProcessDomainObjectClass().isAssignableFrom(domainObject.getClass())) {
113                         hasPermission = true;
114                     } else {
115                         hasPermission = hasPermission(authentication, domainObject);
116 
117                         if (!hasPermission) {
118                             filterer.remove(domainObject);
119 
120                             if (logger.isDebugEnabled()) {
121                                 logger.debug("Principal is NOT authorised for element: " + domainObject);
122                             }
123                         }
124                     }
125                 }
126 
127                 return filterer.getFilteredObject();
128             }
129         }
130 
131         return returnedObject;
132     }
133 }