/* 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.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import java.util.Collection;

 import java.util.HashSet;

 import java.util.Iterator;

 import java.util.Set;

 /**

  * A filter used to filter Collections.

  *

  * @author Ben Alex

  * @author Paulo Neves

  * @version $Id: CollectionFilterer.java 1807 2007-05-10 02:25:15Z vishalpuri $

  */

 class CollectionFilterer implements Filterer {

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

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

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

     private Collection collection;

     // collectionIter offers significant performance optimisations (as

     // per acegisecurity-developer mailing list conversation 19/5/05)

     private Iterator collectionIter;

     private Set removeList;

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

     CollectionFilterer(Collection collection) {

         this.collection = collection;

         // We create a Set of objects to be removed from the Collection,

         // as ConcurrentModificationException prevents removal during

         // iteration, and making a new Collection to be returned is

         // problematic as the original Collection implementation passed

         // to the method may not necessarily be re-constructable (as

         // the Collection(collection) constructor is not guaranteed and

         // manually adding may lose sort order or other capabilities)

         removeList = new HashSet();

     }

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

     /**

      * 

      * @see org.acegisecurity.afterinvocation.Filterer#getFilteredObject()

      */

     public Object getFilteredObject() {

         // Now the Iterator has ended, remove Objects from Collection

         Iterator removeIter = removeList.iterator();

         int originalSize = collection.size();

         while (removeIter.hasNext()) {

             collection.remove(removeIter.next());

         }

         if (logger.isDebugEnabled()) {

             logger.debug("Original collection contained " + originalSize + " elements; now contains "

                 + collection.size() + " elements");

         }

         return collection;

     }

     /**

      * 

      * @see org.acegisecurity.afterinvocation.Filterer#iterator()

      */

     public Iterator iterator() {

         collectionIter = collection.iterator();

         return collectionIter;

     }

     /**

      * 

      * @see org.acegisecurity.afterinvocation.Filterer#remove(java.lang.Object)

      */

     public void remove(Object object) {

         removeList.add(object);

     }

 }