/*
    * 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.spi.impl;
  
  import java.lang.reflect.InvocationTargetException;
  import java.security.AccessController;
  import java.security.PrivilegedActionException;
  import java.security.PrivilegedExceptionAction;
  import java.util.List;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import javax.faces.FacesException;
  import javax.faces.context.ExternalContext;
  
  import org.apache.myfaces.shared.util.ClassUtils;
  import org.apache.myfaces.spi.ServiceProviderFinderFactory;
  import org.apache.myfaces.spi.WebConfigProvider;
  import org.apache.myfaces.spi.WebConfigProviderFactory;
  
  /**
   * The default implementation of WebXmlProviderFactory. Looks for META-INF/service
   * entries of org.apache.myfaces.shared.spi.WebXmlProvider.
   *
   * Returns a new DefaultWebXmlProvider if no custom impl can be found.
   *
   * @author Jakob Korherr
   * @since 2.0.3
   */
  public class DefaultWebConfigProviderFactory extends WebConfigProviderFactory
  {
  
      public static final String WEB_CONFIG_PROVIDER = WebConfigProvider.class.getName();
      
      public static final String WEB_CONFIG_PROVIDER_LIST = WebConfigProvider.class.getName()+".LIST";
  
      private Logger getLogger()
      {
          return Logger.getLogger(DefaultWebConfigProviderFactory.class.getName());
      }
  
      @Override
      public WebConfigProvider getWebConfigProvider(ExternalContext externalContext)
      {
          WebConfigProvider returnValue = null;
          final ExternalContext extContext = externalContext;
          try
          {
              if (System.getSecurityManager() != null)
              {
                  returnValue = AccessController.doPrivileged(new PrivilegedExceptionAction<WebConfigProvider>()
                          {
                              public WebConfigProvider run() throws ClassNotFoundException,
                                      NoClassDefFoundError,
                                      InstantiationException,
                                      IllegalAccessException,
                                      InvocationTargetException,
                                      PrivilegedActionException
                              {
                                  return resolveWebXmlProviderFromService(extContext);
                              }
                          });
              }
              else
              {
                  returnValue = resolveWebXmlProviderFromService(extContext);
              }
          }
          catch (ClassNotFoundException e)
          {
              // ignore
          }
          catch (NoClassDefFoundError e)
          {
              // ignore
          }
          catch (InstantiationException e)
          {
              getLogger().log(Level.SEVERE, "", e);
          }
          catch (IllegalAccessException e)
          {
              getLogger().log(Level.SEVERE, "", e);
         }
         catch (InvocationTargetException e)
         {
             getLogger().log(Level.SEVERE, "", e);
         }
         catch (PrivilegedActionException e)
         {
             throw new FacesException(e);
         }
 
         return returnValue;
     }
 
     private WebConfigProvider resolveWebXmlProviderFromService(
             ExternalContext externalContext) throws ClassNotFoundException,
             NoClassDefFoundError,
             InstantiationException,
             IllegalAccessException,
             InvocationTargetException,
             PrivilegedActionException
     {
         List<String> classList = (List<String>) externalContext.getApplicationMap().get(WEB_CONFIG_PROVIDER_LIST);
         if (classList == null)
         {
             classList = ServiceProviderFinderFactory.getServiceProviderFinder(externalContext).
                     getServiceProviderList(WEB_CONFIG_PROVIDER);
             externalContext.getApplicationMap().put(WEB_CONFIG_PROVIDER_LIST, classList);
         }
 
         return ClassUtils.buildApplicationObject(WebConfigProvider.class, classList, new DefaultWebConfigProvider());
     }
 
 }