/*

  * $Id: EnvironmentScopeExtractor.java 1294456 2012-02-28 04:44:55Z nlebas $

  *

  * 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.freemarker.extractor;

 import java.util.Collections;

 import java.util.Enumeration;

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

 import org.apache.tiles.request.freemarker.FreemarkerRequestException;

 import freemarker.core.Environment;

 import freemarker.template.TemplateModel;

 import freemarker.template.TemplateModelException;

 import freemarker.template.utility.DeepUnwrap;

 /**

  * Extract attributes from {@link Environment} objects as a scope.

  *

  * @version $Rev: 1294456 $ $Date: 2012-02-28 15:44:55 +1100 (Tue, 28 Feb 2012) $

  */

 public class EnvironmentScopeExtractor implements AttributeExtractor {

     /**

      * The environment.

      */

     private Environment request;

     /**

      * Constructor.

      *

      * @param request The environment.

      */

     public EnvironmentScopeExtractor(Environment request) {

         this.request = request;

     }

     @Override

     public void removeValue(String name) {

         request.setVariable(name, null);

     }

     @SuppressWarnings("unchecked")

     @Override

     public Enumeration<String> getKeys() {

         try {

             return Collections.<String> enumeration(request.getKnownVariableNames());

         } catch (TemplateModelException e) {

             throw new FreemarkerRequestException("Cannot iterate variable names correctly", e);

         }

     }

     @Override

     public Object getValue(String key) {

         try {

             TemplateModel variable = request.getVariable(key);

             if (variable != null) {

                 return DeepUnwrap.unwrap(variable);

             }

             return null;

         } catch (TemplateModelException e) {

             throw new FreemarkerRequestException("Cannot get attribute with name '" + key + "'", e);

         }

     }

     @Override

     public void setValue(String key, Object value) {

         try {

             TemplateModel model = request.getObjectWrapper().wrap(value);

             request.setVariable(key, model);

         } catch (TemplateModelException e) {

             throw new FreemarkerRequestException("Error when wrapping an object setting the '" + key + "' attribute", e);

         }

     }

 }