/*

  * $Id: VelocityScopeExtractor.java 1066512 2011-02-02 16:13:31Z apetrelli $

  *

  * 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.velocity.extractor;

 import java.util.Enumeration;

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

 import org.apache.velocity.context.Context;

 /**

  * Extracts attributes from Velocity context..

  *

  * @version $Rev: 1066512 $ $Date: 2011-02-03 03:13:31 +1100 (Thu, 03 Feb 2011) $

  */

 public class VelocityScopeExtractor implements AttributeExtractor {

     /**

      * The Velocity context.

      */

     private Context context;

     /**

      * Constructor.

      *

      * @param context The Velocity context.

      */

     public VelocityScopeExtractor(Context context) {

         this.context = context;

     }

     @Override

     public void removeValue(String name) {

         context.remove(name);

     }

     @Override

     public Enumeration<String> getKeys() {

         return new KeyEnumeration(context.getKeys());

     }

     @Override

     public Object getValue(String key) {

         return context.get(key);

     }

     @Override

     public void setValue(String key, Object value) {

         context.put(key, value);

     }

     /**

      * Enumerates an array.

      */

     private static class KeyEnumeration implements Enumeration<String> {

         /**

          * The current index.

          */

         private int index = 0;

         /**

          * The array to enumerate.

          */

         private Object[] keys;

         /**

          * Constructor.

          *

          * @param keys The array to enumerate.

          */

         public KeyEnumeration(Object[] keys) {

             this.keys = keys;

         }

         @Override

         public boolean hasMoreElements() {

             return index < keys.length;

         }

         @Override

         public String nextElement() {

             return (String) keys[index++];

         }

     }

 }