/*

  * $Id: RemovableKeySet.java 1229087 2012-01-09 10:35:14Z mck $

  *

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.apache.tiles.request.collection;

 import static org.apache.tiles.request.collection.CollectionUtil.*;

 import java.util.Collection;

 import java.util.Enumeration;

 import java.util.LinkedHashSet;

 import java.util.Set;

 import org.apache.tiles.request.attribute.HasRemovableKeys;

 /**

  * Wraps {@link HasRemovableKeys} keys as a set.

  *

  * @version $Rev: 1229087 $ $Date: 2012-01-09 21:35:14 +1100 (Mon, 09 Jan 2012) $

  */

 public class RemovableKeySet extends KeySet {

     /**

      * The request.

      */

     private HasRemovableKeys<?> request;

     /**

      * Constructor.

      *

      * @param request The request.

      */

     public RemovableKeySet(HasRemovableKeys<?> request) {

         super(request);

         this.request = request;

     }

     @Override

     public boolean remove(Object o) {

         String skey = key(o);

         Object previous = request.getValue(skey);

         if (previous != null) {

             request.removeValue(skey);

             return true;

         }

         return false;

     }

     @SuppressWarnings("unchecked")

     @Override

     public boolean removeAll(Collection<?> c) {

         Collection<String> realCollection = (Collection<String>) c;

         boolean retValue = false;

         for (String entry : realCollection) {

             retValue |= remove(entry);

         }

         return retValue;

     }

     @SuppressWarnings("unchecked")

     @Override

     public boolean retainAll(Collection<?> c) {

         Collection<String> realCollection = (Collection<String>) c;

         boolean retValue = false;

         Set<String> keysToRemove = new LinkedHashSet<String>();

         for (Enumeration<String> keys = request.getKeys(); keys.hasMoreElements();) {

             String key = keys.nextElement();

             if (!realCollection.contains(key)) {

                 retValue = true;

                 keysToRemove.add(key);

             }

         }

         for (String key : keysToRemove) {

             request.removeValue(key);

         }

         return retValue;

     }

 }