/*
    * $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;
         }
     }
 }