/*

  * 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.servlet;

 import java.io.InputStream;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.util.Map;

 import java.util.Set;

 import javax.faces.context.ExternalContext;

 import javax.faces.lifecycle.ClientWindow;

 import javax.servlet.ServletContext;

 import org.apache.myfaces.context.ReleaseableExternalContext;

 /**

  * Provides a base implementation of the ExternalContext for Servlet

  * environments. This impl provides all methods which only rely on the

  * ServletContext and thus are also provided at startup and shutdown.

  * 

  * @author Jakob Korherr (latest modification by $Author$)

  * @version $Revision$ $Date$

  */

 public abstract class ServletExternalContextImplBase extends ExternalContext

         implements ReleaseableExternalContext

 {

     private static final String INIT_PARAMETER_MAP_ATTRIBUTE = InitParameterMap.class.getName();

     private ServletContext _servletContext;

     private Map<String, Object> _applicationMap;

     private Map<String, String> _initParameterMap;

     private ClientWindow _clientWindow;

     public ServletExternalContextImplBase(ServletContext servletContext)

     {

         _servletContext = servletContext;

         _applicationMap = null;

         _initParameterMap = null;

         _clientWindow = null;

     }

     public void release()

     {

         _servletContext = null;

         _applicationMap = null;

         _initParameterMap = null;

         _clientWindow = null;

     }

     // ~ Methods which only rely on the ServletContext-------------------------

     @Override

     public Map<String, Object> getApplicationMap()

     {

         if (_applicationMap == null)

         {

             _applicationMap = new ApplicationMap(_servletContext);

         }

         return _applicationMap;

     }

     @Override

     public String getMimeType(String file)

     {

         checkNull(file, "file");

         return _servletContext.getMimeType(file);

     }

     @Override

     public Object getContext()

     {

         return _servletContext;

     }

     @Override

     public String getContextName() 

     {

         return _servletContext.getServletContextName();

     }

     @Override

     public String getInitParameter(final String s)

     {

         if (s == null)

         {

             throw new NullPointerException("Init parameter name cannot be null");

         }

         return _servletContext.getInitParameter(s);

     }

     @Override

     @SuppressWarnings("unchecked")

     public Map<String, String> getInitParameterMap()

     {

         if (_initParameterMap == null)

         {

             // We cache it as an attribute in ServletContext itself (is this circular reference a problem?)

             _initParameterMap = (Map<String, String>) _servletContext.getAttribute(INIT_PARAMETER_MAP_ATTRIBUTE);

             if (_initParameterMap == null)

             {

                 _initParameterMap = new InitParameterMap(_servletContext);

                 _servletContext.setAttribute(INIT_PARAMETER_MAP_ATTRIBUTE, _initParameterMap);

             }

         }

         return _initParameterMap;

     }

     @Override

     public URL getResource(final String path) throws MalformedURLException

     {

         checkNull(path, "path");

         return _servletContext.getResource(path);

     }

     @Override

     public InputStream getResourceAsStream(final String path)

     {

         checkNull(path, "path");

         return _servletContext.getResourceAsStream(path);

     }

     @Override

     @SuppressWarnings("unchecked")

     public Set<String> getResourcePaths(final String path)

     {

         checkNull(path, "path");

         return _servletContext.getResourcePaths(path);

     }

     @Override

     public void log(final String message)

     {

         checkNull(message, "message");

         _servletContext.log(message);

     }

     @Override

     public void log(final String message, final Throwable exception)

     {

         checkNull(message, "message");

         checkNull(exception, "exception");

         _servletContext.log(message, exception);

     }

     @Override

     public String getRealPath(String path)

     {

         checkNull(path, "path");

         return _servletContext.getRealPath(path);

     }

     public ClientWindow getClientWindow()

     {

         return _clientWindow;

     }

     public void setClientWindow(ClientWindow window)

     {

         _clientWindow = window;

     }

     @Override

     public String getApplicationContextPath() 

     {

         return _servletContext.getContextPath();

     }

     // ~ Methods which verify some required behavior---------------------------

     protected void checkNull(final Object o, final String param)

     {

         if (o == null)

         {

             throw new NullPointerException(param + " can not be null.");

         }

     }

 }