/*
    * 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.myfaces.context;
  
  import javax.faces.FacesException;
  import javax.faces.FactoryFinder;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.ExternalContextFactory;
  import javax.faces.context.FlashFactory;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  
  import org.apache.myfaces.context.servlet.ServletExternalContextImpl;
  
  /**
   * @author Leonardo Uribe (latest modification by $Author$)
   * @version $Revision$ $Date$
   * 
   * @since 2.0
   */
  public class ExternalContextFactoryImpl extends ExternalContextFactory
  {
  
      public static final String EXTERNAL_CONTEXT_KEY = 
          "org.apache.myfaces.context.servlet.ServletExternalContextImpl";
      
      private final FlashFactory _flashFactory;
      
      public ExternalContextFactoryImpl()
      {
          _flashFactory = (FlashFactory) FactoryFinder.getFactory(
                      FactoryFinder.FLASH_FACTORY);
      }
      
      @Override
      public ExternalContext getExternalContext(Object context, Object request,
              Object response) throws FacesException
      {
          if (context == null)
          {
              throw new NullPointerException("context");
          }
          if (request == null)
          {
              throw new NullPointerException("request");
          }
          if (response == null)
          {
              throw new NullPointerException("response");
          }
  
          if (context instanceof ServletContext)
          {
              ExternalContext externalContext = new ServletExternalContextImpl(
                      (ServletContext) context, (ServletRequest) request, (ServletResponse) response,
                      _flashFactory);
              
              externalContext.getRequestMap().put(EXTERNAL_CONTEXT_KEY, externalContext);
              
              return externalContext;
          }
          
          throw new FacesException("Unsupported context type " + context.getClass().getName());
      }
  }