/*

  * $Id: ScopeMap.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.Iterator;

 import java.util.LinkedHashSet;

 import java.util.Map;

 import java.util.Set;

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

 /**

  * Exposes a scope context as a <String, Object> map.

  *

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

  */

 public class ScopeMap extends ReadOnlyEnumerationMap<Object> {

     /**

      * The context to read.

      */

     private AttributeExtractor context;

     /**

      * Constructor.

      *

      * @param context The servlet context to use.

      */

     public ScopeMap(AttributeExtractor context) {

         super(context);

         this.context = context;

     }

     /** {@inheritDoc} */

     public void clear() {

         Enumeration<String> keys = context.getKeys();

         while (keys.hasMoreElements()) {

             context.removeValue(keys.nextElement());

         }

     }

     /** {@inheritDoc} */

     public Set<Map.Entry<String, Object>> entrySet() {

         return new ScopeEntrySet();

     }

     /** {@inheritDoc} */

     public Set<String> keySet() {

         return new RemovableKeySet(context);

     }

     /** {@inheritDoc} */

     public Object put(String key, Object value) {

         String skey = key(key);

         Object previous = context.getValue(skey);

         context.setValue(skey, value);

         return previous;

     }

     /** {@inheritDoc} */

     public void putAll(Map<? extends String, ? extends Object> map) {

         Iterator<? extends String> keys = map.keySet().iterator();

         while (keys.hasNext()) {

             String key = keys.next();

             context.setValue(key, map.get(key));

         }

     }

     /** {@inheritDoc} */

     public Object remove(Object key) {

         String skey = key(key);

         Object previous = context.getValue(skey);

         context.removeValue(skey);

         return (previous);

     }

     /**

      * Entry set implementation for {@link ScopeMap}.

      */

     private class ScopeEntrySet extends ReadOnlyEnumerationMap<Object>.ReadOnlyEnumerationMapEntrySet {

         @Override

         public boolean add(java.util.Map.Entry<String, Object> e) {

             String key = e.getKey();

             Object value = e.getValue();

             Object oldValue = get(key);

             if (oldValue == null || !oldValue.equals(value)) {

                 context.setValue(key, value);

                 return true;

             }

             return false;

         }

         @Override

         public boolean addAll(

                 Collection<? extends java.util.Map.Entry<String, Object>> c) {

             boolean retValue = false;

             for (Map.Entry<String, Object> entry : c) {

                 retValue |= add(entry);

             }

             return retValue;

         }

         @Override

         public void clear() {

             ScopeMap.this.clear();

         }

         @SuppressWarnings("unchecked")

         @Override

         public boolean remove(Object o) {

             Map.Entry<String, Object> entry = (java.util.Map.Entry<String, Object>) o;

             String key = entry.getKey();

             Object currentValue = context.getValue(key);

             if (currentValue != null && currentValue.equals(entry.getValue())) {

                 context.removeValue(key);

                 return true;

             }

             return false;

         }

         @SuppressWarnings("unchecked")

         @Override

         public boolean removeAll(Collection<?> c) {

             Collection<Map.Entry<String, Object>> realCollection = (Collection<java.util.Map.Entry<String, Object>>) c;

             boolean retValue = false;

             for (Map.Entry<String, Object> entry : realCollection) {

                 retValue |= remove(entry);

             }

             return retValue;

         }

         @SuppressWarnings("unchecked")

         @Override

         public boolean retainAll(Collection<?> c) {

             Collection<Map.Entry<String, Object>> realCollection = (Collection<java.util.Map.Entry<String, Object>>) c;

             boolean retValue = false;

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

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

                 String key = keys.nextElement();

                 Object value = context.getValue(key);

                 Map.Entry<String, Object> entry = new MapEntry<String, Object>(key, value, false);

                 if (!realCollection.contains(entry)) {

                     retValue = true;

                     keysToRemove.add(key);

                 }

             }

             for (String key : keysToRemove) {

                 context.removeValue(key);

             }

             return retValue;

         }

     }

 }